From a4107797faf0d791da030887cc36da767662b1fb Mon Sep 17 00:00:00 2001
From: Anton Afanasyeu <a.afanasieff@gmail.com>
Date: Tue, 19 May 2026 19:43:06 +0200
Subject: [PATCH] snap

---
 app/build.gradle                              |   1 +
 app/src/main/AndroidManifest.xml              |  16 +
 .../com/foxx/androidcast/AppPreferences.java  |   2 +-
 .../DeveloperSettingsActivity.java            |   4 +
 .../foxx/androidcast/media/RgbToYuv420.java   |   9 +-
 .../media/codec/LibvpxVideoEncoderSink.java   | 126 +++--
 .../foxx/androidcast/network/CastSession.java |  62 ++-
 .../androidcast/network/UdpCastTransport.java |   3 +
 .../receiver/ReceiverCastService.java         |  36 +-
 .../receiver/ReceiverPlaybackActivity.java    |  29 +-
 .../androidcast/receiver/ReceiverSession.java |   4 +
 .../androidcast/sender/CastFanoutPump.java    |  12 +-
 .../foxx/androidcast/sender/CastSendPump.java |   8 +
 .../androidcast/sender/ScreenCastService.java |  15 +-
 .../stats/SessionEventJournal.java            |  79 +++
 .../stats/SessionStatsContext.java            |  57 +++
 .../stats/SessionStatsEventMapper.java        |  44 ++
 .../stats/SessionStatsRecorder.java           |  82 ++-
 .../androidcast/stats/SessionStatsStore.java  |  45 +-
 .../androidcast/stats/ui/ChartTickHelper.java |  79 +++
 .../stats/ui/SessionBarChartView.java         | 110 ++++
 .../stats/ui/SessionLineChartView.java        | 481 ++++++++++++++++++
 .../androidcast/stats/ui/SessionRecord.java   | 228 +++++++++
 .../ui/SessionStatsAnalyzerActivity.java      | 182 +++++++
 .../stats/ui/SessionStatsListAdapter.java     | 105 ++++
 .../stats/ui/SessionStatsParser.java          |  22 +
 .../layout/activity_developer_settings.xml    |   9 +-
 .../activity_session_stats_analyzer.xml       | 128 +++++
 .../main/res/layout/item_session_stats.xml    |  37 ++
 app/src/main/res/values/strings.xml           |  13 +
 app/src/main/res/xml/file_paths.xml           |   4 +
 .../stats/SessionStatsEventMapperTest.java    |  38 ++
 .../stats/SessionStatsStoreTest.java          |  28 +
 desktop/README.md                             |   2 +-
 .../foxx/androidcast/studio/ChartTicks.java   |  79 +++
 .../androidcast/studio/SessionChartPane.java  | 468 +++++++++++++----
 .../androidcast/studio/SessionDocument.java   |  35 +-
 .../androidcast/studio/SessionStudioApp.java  |  99 ++--
 pull_stats.sh                                 |  29 +-
 rebuild.sh                                    |  46 +-
 40 files changed, 2602 insertions(+), 254 deletions(-)
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/SessionEventJournal.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/SessionStatsContext.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/SessionStatsEventMapper.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/ChartTickHelper.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionBarChartView.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionLineChartView.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionRecord.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsAnalyzerActivity.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsListAdapter.java
 create mode 100644 app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsParser.java
 create mode 100644 app/src/main/res/layout/activity_session_stats_analyzer.xml
 create mode 100644 app/src/main/res/layout/item_session_stats.xml
 create mode 100644 app/src/main/res/xml/file_paths.xml
 create mode 100644 app/src/test/java/com/foxx/androidcast/stats/SessionStatsEventMapperTest.java
 create mode 100644 desktop/session-studio/src/main/java/com/foxx/androidcast/studio/ChartTicks.java

diff --git a/app/build.gradle b/app/build.gradle
index 4d4aeb5..9b59889 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -93,6 +93,7 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.7.0'
     implementation 'com.google.android.material:material:1.12.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.2.0'
+    implementation 'androidx.recyclerview:recyclerview:1.3.2'
     implementation 'com.google.android.gms:play-services-cronet:18.1.0'
 
     testImplementation 'junit:junit:4.13.2'
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index e31e0a9..8ef1fb7 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -64,6 +64,22 @@
             android:label="@string/developer_settings_title"
             android:parentActivityName=".MainActivity" />
 
+        <activity
+            android:name=".stats.ui.SessionStatsAnalyzerActivity"
+            android:exported="false"
+            android:label="@string/session_stats_title"
+            android:parentActivityName=".DeveloperSettingsActivity" />
+
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
         <activity
             android:name=".receiver.ReceiverPlaybackActivity"
             android:exported="false"
diff --git a/app/src/main/java/com/foxx/androidcast/AppPreferences.java b/app/src/main/java/com/foxx/androidcast/AppPreferences.java
index c2a96cb..a432187 100644
--- a/app/src/main/java/com/foxx/androidcast/AppPreferences.java
+++ b/app/src/main/java/com/foxx/androidcast/AppPreferences.java
@@ -106,7 +106,7 @@ public final class AppPreferences {
         prefs(context).edit().putBoolean(KEY_DEV_RECEIVER_DEBUG_OVERLAY, show).apply();
     }
 
-    /** Developer: write anonymous session_*.json files (default on). */
+    /** Developer: write anonymous session_send_* / session_recv_* JSON (default on). */
     public static boolean isGrabSessionStats(Context context) {
         return prefs(context).getBoolean(KEY_DEV_GRAB_SESSION_STATS, true);
     }
diff --git a/app/src/main/java/com/foxx/androidcast/DeveloperSettingsActivity.java b/app/src/main/java/com/foxx/androidcast/DeveloperSettingsActivity.java
index b54e1b7..be0877d 100644
--- a/app/src/main/java/com/foxx/androidcast/DeveloperSettingsActivity.java
+++ b/app/src/main/java/com/foxx/androidcast/DeveloperSettingsActivity.java
@@ -9,6 +9,7 @@ import android.widget.Toast;
 import androidx.appcompat.app.AppCompatActivity;
 
 import com.foxx.androidcast.media.CodecPriorityCatalog;
+import com.foxx.androidcast.stats.ui.SessionStatsAnalyzerActivity;
 
 /** Hidden developer settings (opened via version label easter egg). */
 public class DeveloperSettingsActivity extends AppCompatActivity {
@@ -31,6 +32,9 @@ public class DeveloperSettingsActivity extends AppCompatActivity {
 
         refreshFromPreferences(debugOverlay, codecScores, sessionStats);
 
+        findViewById(R.id.btn_open_session_stats).setOnClickListener(v ->
+                startActivity(new android.content.Intent(this, SessionStatsAnalyzerActivity.class)));
+
         reloadCodecs.setOnClickListener(v -> {
             String summary = CodecPriorityCatalog.reload(this);
             Toast.makeText(this, summary, Toast.LENGTH_LONG).show();
diff --git a/app/src/main/java/com/foxx/androidcast/media/RgbToYuv420.java b/app/src/main/java/com/foxx/androidcast/media/RgbToYuv420.java
index af790f0..124344d 100644
--- a/app/src/main/java/com/foxx/androidcast/media/RgbToYuv420.java
+++ b/app/src/main/java/com/foxx/androidcast/media/RgbToYuv420.java
@@ -42,8 +42,15 @@ public final class RgbToYuv420 {
         int height = image.getHeight();
         int need = bufferSize(width, height);
         byte[] out = scratch != null && scratch.length >= need ? scratch : new byte[need];
-        Image.Plane plane = image.getPlanes()[0];
+        Image.Plane[] planes = image.getPlanes();
+        if (planes == null || planes.length == 0) {
+            return null;
+        }
+        Image.Plane plane = planes[0];
         java.nio.ByteBuffer buffer = plane.getBuffer();
+        if (buffer == null) {
+            return null;
+        }
         int rowStride = plane.getRowStride();
         int pixelStride = plane.getPixelStride();
         int[] argb = new int[width * height];
diff --git a/app/src/main/java/com/foxx/androidcast/media/codec/LibvpxVideoEncoderSink.java b/app/src/main/java/com/foxx/androidcast/media/codec/LibvpxVideoEncoderSink.java
index 8030046..1a4d87b 100644
--- a/app/src/main/java/com/foxx/androidcast/media/codec/LibvpxVideoEncoderSink.java
+++ b/app/src/main/java/com/foxx/androidcast/media/codec/LibvpxVideoEncoderSink.java
@@ -18,6 +18,8 @@ import com.foxx.androidcast.media.codec.jni.VpxEncodedFrame;
 import com.foxx.androidcast.sender.VideoEncoder;
 
 import java.io.IOException;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Software VP8/VP9 via libvpx when {@link NativeCodecBridge#isLibvpxAvailable()}.
@@ -30,17 +32,15 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
     private final VideoEncoder hwFallback = new VideoEncoder();
 
     private Callback callback;
-    private long nativeHandle;
-    private boolean nativeActive;
+    private final AtomicLong nativeHandle = new AtomicLong();
     private int width;
     private int height;
     private String mime;
     private byte[] yuvScratch;
     private boolean forceKeyframe;
 
-    private HandlerThread captureThread;
-    private Handler captureHandler;
-    private ImageReader imageReader;
+    /** Active capture pipeline; {@link #releaseCapture()} swaps it out via {@code getAndSet(null)}. */
+    private final AtomicReference<CapturePipeline> capturePipeline = new AtomicReference<>();
 
     public LibvpxVideoEncoderSink(CastSettings.VideoCodec preference) {
         this.preference = preference;
@@ -48,16 +48,17 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
 
     @Override
     public Surface getInputSurface() {
-        if (nativeActive && imageReader != null) {
-            return imageReader.getSurface();
+        CapturePipeline pipe = capturePipeline.get();
+        if (nativeHandle.get() != 0L && pipe != null) {
+            return pipe.reader.getSurface();
         }
         return hwFallback.getInputSurface();
     }
 
     @Override
     public void requestKeyframe() {
-        if (nativeActive) {
-            NativeCodecBridge.vpxRequestKeyframe(nativeHandle);
+        if (nativeHandle.get() != 0L) {
+            NativeCodecBridge.vpxRequestKeyframe(nativeHandle.get());
             forceKeyframe = true;
         } else {
             hwFallback.requestKeyframe();
@@ -68,6 +69,7 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
     public Surface prepare(int width, int height, String mime, CastTuningEngine.EffectiveParams params,
             Callback callback) throws IOException {
         releaseCapture();
+        releaseNativeEncoder();
         this.callback = callback;
         this.width = width;
         this.height = height;
@@ -75,38 +77,36 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
         yuvScratch = new byte[RgbToYuv420.bufferSize(width, height)];
 
         int bitrateKbps = Math.max(500, params.videoBitrate / 1000);
-        nativeHandle = NativeCodecBridge.vpxEncoderCreate(mime, width, height, bitrateKbps);
-        nativeActive = nativeHandle != 0L;
-        if (!nativeActive) {
+        long handle = NativeCodecBridge.vpxEncoderCreate(mime, width, height, bitrateKbps);
+        if (handle == 0L) {
             Log.w(TAG, "libvpx encoder init failed; using MediaCodec for surface capture");
             CodecSessionRegistry.setVideoBackend(VideoCodecBackend.MEDIA_CODEC_HW, mime);
             return hwFallback.prepare(width, height, mime, params, callback);
         }
+        nativeHandle.set(handle);
 
         CodecSessionRegistry.setVideoBackend(VideoCodecBackend.LIBVPX_NATIVE, mime);
-        captureThread = new HandlerThread("libvpx-capture");
-        captureThread.start();
-        captureHandler = new Handler(captureThread.getLooper());
-        imageReader = ImageReader.newInstance(width, height, PixelFormat.RGBA_8888, 2);
-        imageReader.setOnImageAvailableListener(this::onImageAvailable, captureHandler);
+        CapturePipeline pipe = CapturePipeline.create(width, height, this::onImageAvailable);
+        capturePipeline.set(pipe);
         callback.onConfig(width, height, null, null);
         Log.i(TAG, "libvpx surface encoder " + width + "x" + height + " mime=" + mime);
-        return imageReader.getSurface();
+        return pipe.reader.getSurface();
     }
 
     @Override
     public void prepareBufferInput(int width, int height, String mime, CastTuningEngine.EffectiveParams params,
             Callback callback) throws IOException {
         releaseCapture();
+        releaseNativeEncoder();
         this.width = width;
         this.height = height;
         this.mime = mime;
         this.callback = callback;
         yuvScratch = new byte[RgbToYuv420.bufferSize(width, height)];
         int bitrateKbps = Math.max(500, params.videoBitrate / 1000);
-        nativeHandle = NativeCodecBridge.vpxEncoderCreate(mime, width, height, bitrateKbps);
-        nativeActive = nativeHandle != 0L;
-        if (nativeActive) {
+        long handle = NativeCodecBridge.vpxEncoderCreate(mime, width, height, bitrateKbps);
+        if (handle != 0L) {
+            nativeHandle.set(handle);
             CodecSessionRegistry.setVideoBackend(VideoCodecBackend.LIBVPX_NATIVE, mime);
             callback.onConfig(width, height, null, null);
             return;
@@ -116,26 +116,40 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
     }
 
     private void onImageAvailable(ImageReader reader) {
-        if (!nativeActive || callback == null) {
+        CapturePipeline pipe = capturePipeline.get();
+        if (pipe == null || pipe.reader != reader || callback == null) {
+            return;
+        }
+        long handle = nativeHandle.get();
+        if (handle == 0L) {
             return;
         }
         try (Image image = reader.acquireLatestImage()) {
             if (image == null) {
                 return;
             }
+            if (image.getWidth() != width || image.getHeight() != height) {
+                return;
+            }
             byte[] yuv = RgbToYuv420.fromRgbaImage(image, yuvScratch);
             if (yuv == null) {
                 return;
             }
+            if (capturePipeline.get() != pipe) {
+                return;
+            }
             long ptsUs = image.getTimestamp() / 1000L;
-            emitEncodedFrame(yuv, ptsUs);
+            emitEncodedFrame(handle, yuv, ptsUs);
         } catch (Exception e) {
             Log.w(TAG, "Capture frame skipped: " + e.getMessage());
         }
     }
 
-    private void emitEncodedFrame(byte[] yuv, long ptsUs) {
-        VpxEncodedFrame frame = NativeCodecBridge.vpxEncodeYuvFrame(nativeHandle, yuv, ptsUs, forceKeyframe);
+    private void emitEncodedFrame(long handle, byte[] yuv, long ptsUs) {
+        if (nativeHandle.get() != handle) {
+            return;
+        }
+        VpxEncodedFrame frame = NativeCodecBridge.vpxEncodeYuvFrame(handle, yuv, ptsUs, forceKeyframe);
         forceKeyframe = false;
         if (frame != null && frame.data != null && callback != null) {
             callback.onEncodedFrame(ptsUs, frame.keyFrame, frame.data);
@@ -144,43 +158,73 @@ public final class LibvpxVideoEncoderSink implements VideoEncoderSink {
 
     @Override
     public void queueBitmapFrame(Bitmap bitmap, long ptsUs) {
-        if (!nativeActive) {
+        long handle = nativeHandle.get();
+        if (handle == 0L) {
             hwFallback.queueBitmapFrame(bitmap, ptsUs);
             return;
         }
         byte[] yuv = RgbToYuv420.fromBitmap(bitmap, RgbToYuv420.Layout.I420);
-        emitEncodedFrame(yuv, ptsUs);
+        emitEncodedFrame(handle, yuv, ptsUs);
     }
 
     @Override
     public void queueYuvFrame(byte[] yuv, long ptsUs) {
-        if (!nativeActive) {
+        long handle = nativeHandle.get();
+        if (handle == 0L) {
             hwFallback.queueYuvFrame(yuv, ptsUs);
             return;
         }
-        emitEncodedFrame(yuv, ptsUs);
+        emitEncodedFrame(handle, yuv, ptsUs);
     }
 
     @Override
     public void stop() {
-        if (nativeActive) {
-            NativeCodecBridge.vpxEncoderRelease(nativeHandle);
-            nativeHandle = 0L;
-            nativeActive = false;
-        }
         releaseCapture();
+        releaseNativeEncoder();
         hwFallback.stop();
     }
 
     private void releaseCapture() {
-        if (imageReader != null) {
-            imageReader.close();
-            imageReader = null;
+        CapturePipeline old = capturePipeline.getAndSet(null);
+        if (old != null) {
+            old.release();
         }
-        if (captureThread != null) {
-            captureThread.quitSafely();
-            captureThread = null;
-            captureHandler = null;
+    }
+
+    private void releaseNativeEncoder() {
+        long handle = nativeHandle.getAndSet(0L);
+        if (handle != 0L) {
+            NativeCodecBridge.vpxEncoderRelease(handle);
+        }
+    }
+
+    private static final class CapturePipeline {
+        final ImageReader reader;
+        final HandlerThread thread;
+
+        private CapturePipeline(ImageReader reader, HandlerThread thread) {
+            this.reader = reader;
+            this.thread = thread;
+        }
+
+        static CapturePipeline create(int width, int height, ImageReader.OnImageAvailableListener listener) {
+            HandlerThread thread = new HandlerThread("libvpx-capture");
+            thread.start();
+            Handler handler = new Handler(thread.getLooper());
+            ImageReader reader = ImageReader.newInstance(width, height, PixelFormat.RGBA_8888, 2);
+            reader.setOnImageAvailableListener(listener, handler);
+            return new CapturePipeline(reader, thread);
+        }
+
+        void release() {
+            reader.setOnImageAvailableListener(null, null);
+            reader.close();
+            thread.quitSafely();
+            try {
+                thread.join(2000L);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
         }
     }
 
diff --git a/app/src/main/java/com/foxx/androidcast/network/CastSession.java b/app/src/main/java/com/foxx/androidcast/network/CastSession.java
index 80b4a10..877be8c 100644
--- a/app/src/main/java/com/foxx/androidcast/network/CastSession.java
+++ b/app/src/main/java/com/foxx/androidcast/network/CastSession.java
@@ -5,6 +5,7 @@ import com.foxx.androidcast.media.CodecNegotiator;
 import com.foxx.androidcast.media.CodecPriorityCatalog;
 import com.foxx.androidcast.media.codec.PassthroughCodecPolicy;
 import com.foxx.androidcast.sender.CodecCatalog;
+import com.foxx.androidcast.stats.SessionStatsContext;
 
 import java.io.IOException;
 import java.util.List;
@@ -55,20 +56,28 @@ public class CastSession {
     }
 
     public HandshakeResult clientHandshake(String deviceName, String pin, CastSettings settings) throws IOException {
-        transport.send(CastProtocol.MSG_HELLO, CastProtocol.helloPayload(deviceName));
-        transport.send(CastProtocol.MSG_AUTH, CastProtocol.authPayload(pin));
-        CastProtocol.Message reply = transport.receive(10_000);
+        byte[] hello = CastProtocol.helloPayload(deviceName);
+        transport.send(CastProtocol.MSG_HELLO, hello);
+        recordOutbound(CastProtocol.MSG_HELLO, hello);
+        byte[] auth = CastProtocol.authPayload(pin);
+        transport.send(CastProtocol.MSG_AUTH, auth);
+        recordOutbound(CastProtocol.MSG_AUTH, auth);
+        CastProtocol.Message reply = receive(10_000);
         if (reply == null || reply.type != CastProtocol.MSG_AUTH_OK) {
             throw new IOException("Authentication failed");
         }
-        transport.send(CastProtocol.MSG_CAST_SETTINGS, CastProtocol.castSettingsPayload(settings));
-        transport.send(CastProtocol.MSG_CODEC_CAPS, CastProtocol.codecCapsPayload(CodecCatalog.localEncoderMimes()));
+        byte[] castSettings = CastProtocol.castSettingsPayload(settings);
+        transport.send(CastProtocol.MSG_CAST_SETTINGS, castSettings);
+        recordOutbound(CastProtocol.MSG_CAST_SETTINGS, castSettings);
+        byte[] codecCaps = CastProtocol.codecCapsPayload(CodecCatalog.localEncoderMimes());
+        transport.send(CastProtocol.MSG_CODEC_CAPS, codecCaps);
+        recordOutbound(CastProtocol.MSG_CODEC_CAPS, codecCaps);
 
         String negotiated = null;
         CastSettings receiverAdvertisement = null;
         long deadline = System.currentTimeMillis() + 15_000;
         while (System.currentTimeMillis() < deadline) {
-            CastProtocol.Message msg = transport.receive(2_000);
+            CastProtocol.Message msg = receive(2_000);
             if (msg == null) {
                 continue;
             }
@@ -94,7 +103,7 @@ public class CastSession {
         List<String> senderCaps = null;
         long deadline = System.currentTimeMillis() + 30_000;
         while (System.currentTimeMillis() < deadline) {
-            CastProtocol.Message msg = transport.receive(2_000);
+            CastProtocol.Message msg = receive(2_000);
             if (msg == null) {
                 continue;
             }
@@ -106,8 +115,10 @@ public class CastSession {
                     if (CastProtocol.pinMatches(msg.payload, expectedPin)) {
                         authed = true;
                         transport.send(CastProtocol.MSG_AUTH_OK, new byte[0]);
+                        recordOutbound(CastProtocol.MSG_AUTH_OK, new byte[0]);
                     } else {
                         transport.send(CastProtocol.MSG_AUTH_FAIL, new byte[0]);
+                        recordOutbound(CastProtocol.MSG_AUTH_FAIL, new byte[0]);
                         throw new IOException("Bad PIN");
                     }
                     break;
@@ -130,13 +141,18 @@ public class CastSession {
                 receiverAdvert.setStreamProtection(
                         com.foxx.androidcast.network.transport.StreamProtectionCapability
                                 .handshakeAdvertisement());
-                transport.send(CastProtocol.MSG_RECEIVER_CAST_SETTINGS,
-                        CastProtocol.castSettingsPayload(receiverAdvert));
+                byte[] recvSettings = CastProtocol.castSettingsPayload(receiverAdvert);
+                transport.send(CastProtocol.MSG_RECEIVER_CAST_SETTINGS, recvSettings);
+                recordOutbound(CastProtocol.MSG_RECEIVER_CAST_SETTINGS, recvSettings);
                 List<String> receiverCaps = CodecCatalog.localDecoderMimes();
-                transport.send(CastProtocol.MSG_CODEC_CAPS, CastProtocol.codecCapsPayload(receiverCaps));
+                byte[] recvCaps = CastProtocol.codecCapsPayload(receiverCaps);
+                transport.send(CastProtocol.MSG_CODEC_CAPS, recvCaps);
+                recordOutbound(CastProtocol.MSG_CODEC_CAPS, recvCaps);
                 String mime = CodecNegotiator.negotiate(senderCaps, receiverCaps,
                         PassthroughCodecPolicy.forNegotiation(remote.getVideoCodec()), remote, "receiver");
-                transport.send(CastProtocol.MSG_CODEC_SELECTED, CastProtocol.codecSelectedPayload(mime));
+                byte[] selected = CastProtocol.codecSelectedPayload(mime);
+                transport.send(CastProtocol.MSG_CODEC_SELECTED, selected);
+                recordOutbound(CastProtocol.MSG_CODEC_SELECTED, selected);
                 remote.setNegotiatedVideoMime(mime);
                 return new HandshakeResult(senderName, remote, receiverAdvert, mime);
             }
@@ -148,8 +164,30 @@ public class CastSession {
         transport.send(type, payload);
     }
 
+    private static void recordOutbound(byte type, byte[] payload) {
+        int size = payload != null ? payload.length : 0;
+        SessionStatsContext.recordOutboundMessage(type, false, size);
+    }
+
+    private static void recordInbound(CastProtocol.Message msg) {
+        if (msg == null) {
+            return;
+        }
+        boolean keyFrame = false;
+        if (msg.type == CastProtocol.MSG_VIDEO_FRAME) {
+            try {
+                keyFrame = CastProtocol.parseVideoFrame(msg.payload).keyFrame;
+            } catch (IOException ignored) {
+            }
+        }
+        int size = msg.payload != null ? msg.payload.length : 0;
+        SessionStatsContext.recordInboundMessage(msg.type, keyFrame, size);
+    }
+
     public CastProtocol.Message receive(int timeoutMs) throws IOException {
-        return transport.receive(timeoutMs);
+        CastProtocol.Message msg = transport.receive(timeoutMs);
+        recordInbound(msg);
+        return msg;
     }
 
     public void releaseConnection() {
diff --git a/app/src/main/java/com/foxx/androidcast/network/UdpCastTransport.java b/app/src/main/java/com/foxx/androidcast/network/UdpCastTransport.java
index d21cc13..2a2f075 100644
--- a/app/src/main/java/com/foxx/androidcast/network/UdpCastTransport.java
+++ b/app/src/main/java/com/foxx/androidcast/network/UdpCastTransport.java
@@ -15,6 +15,7 @@ import com.foxx.androidcast.network.transport.TransportLossStats;
 import com.foxx.androidcast.network.transport.TransportStatsProvider;
 import com.foxx.androidcast.network.transport.fec.FecEncodedGroup;
 import com.foxx.androidcast.network.transport.fec.FecShardWire;
+import com.foxx.androidcast.stats.SessionStatsContext;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -242,6 +243,7 @@ public class UdpCastTransport implements CastTransport, TransportStatsProvider {
             byte[] packet = buildPacket(type, messageId, i, fragments, body, offset, len, body.length);
             DatagramPacket dp = new DatagramPacket(packet, packet.length, peer);
             socket.send(dp);
+            SessionStatsContext.onDatagramSent(packet.length);
             synchronized (lossStats) {
                 lossStats.datagramsSent++;
             }
@@ -266,6 +268,7 @@ public class UdpCastTransport implements CastTransport, TransportStatsProvider {
                 byte[] buf = new byte[CastConfig.UDP_CHUNK_SIZE + 64];
                 DatagramPacket dp = new DatagramPacket(buf, buf.length);
                 socket.receive(dp);
+                SessionStatsContext.onDatagramReceived(dp.getLength());
                 synchronized (lossStats) {
                     lossStats.datagramsReceived++;
                 }
diff --git a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverCastService.java b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverCastService.java
index d7f5a61..9d5e71a 100644
--- a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverCastService.java
+++ b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverCastService.java
@@ -36,6 +36,7 @@ import com.foxx.androidcast.discovery.DiscoveryManager;
 import com.foxx.androidcast.network.transport.TransportLossStats;
 import com.foxx.androidcast.network.transport.TransportLossStatsBridge;
 import com.foxx.androidcast.network.control.NetworkStatsSnapshot;
+import com.foxx.androidcast.stats.SessionStatsContext;
 import com.foxx.androidcast.stats.SessionStatsRecorder;
 import com.foxx.androidcast.stats.SessionStatsStore;
 import com.foxx.androidcast.network.control.PassThroughNetworkControlPlane;
@@ -255,6 +256,17 @@ public class ReceiverCastService extends Service {
                 mainHandler.post(ReceiverCastService.this::startDiscoveryAnnouncing);
             }
 
+            @Override
+            public void onCastSessionStarting() {
+                if (AppPreferences.isGrabSessionStats(ReceiverCastService.this)) {
+                    if (sessionStatsRecorder == null) {
+                        sessionStatsRecorder = new SessionStatsRecorder("recv",
+                                settings.getTransport());
+                        SessionStatsContext.bind(sessionStatsRecorder);
+                    }
+                }
+            }
+
             @Override
             public void onStatus(String s) {
                 updateStatus(s);
@@ -393,7 +405,8 @@ public class ReceiverCastService extends Service {
         castEnded = false;
         if (AppPreferences.isGrabSessionStats(this)) {
             if (sessionStatsRecorder == null) {
-                sessionStatsRecorder = new SessionStatsRecorder("receiver", settings.getTransport());
+                sessionStatsRecorder = new SessionStatsRecorder("recv", settings.getTransport());
+                SessionStatsContext.bind(sessionStatsRecorder);
                 sessionStatsRecorder.setClientCount(1);
             }
             sessionStatsRecorder.mergeSettings(remoteSettings);
@@ -460,7 +473,8 @@ public class ReceiverCastService extends Service {
     }
 
     private void checkStreamIdle() {
-        if (phase != Phase.STREAMING || streamIdle || lastVideoFrameMs <= 0) {
+        if (phase != Phase.STREAMING || streamIdle || lastVideoFrameMs <= 0
+                || awaitingKeyframe || reconfiguring) {
             return;
         }
         long idleMs = System.currentTimeMillis() - lastVideoFrameMs;
@@ -487,14 +501,14 @@ public class ReceiverCastService extends Service {
     /** Stops decode, shows robot overlay; keeps TCP session if still connected. */
     private void enterAwaitingMode(int messageResId, boolean fullReset) {
         streamIdle = true;
-        hasPendingConfig = false;
         enterAwaitingKeyframe();
-        resetDecoderState();
-        if (videoDecoder != null) {
-            videoDecoder.release();
-            videoDecoder = VideoDecoderFactory.createDecoder();
-        }
         if (fullReset) {
+            hasPendingConfig = false;
+            resetDecoderState();
+            if (videoDecoder != null) {
+                videoDecoder.release();
+                videoDecoder = VideoDecoderFactory.createDecoder();
+            }
             streamMetrics.reset();
         }
         broadcastStreamIdle();
@@ -576,6 +590,7 @@ public class ReceiverCastService extends Service {
         }
         reconfiguring = true;
         enterAwaitingKeyframe();
+        lastVideoFrameMs = System.currentTimeMillis();
         openPlaybackAwaiting(R.string.playback_awaiting_stream);
         pendingWidth = size.width;
         pendingHeight = size.height;
@@ -684,7 +699,6 @@ public class ReceiverCastService extends Service {
         if (!hasPendingConfig || attachedSurface == null || !attachedSurface.isValid()) {
             Log.i(TAG, "Decoder waiting: config=" + hasPendingConfig
                     + " surface=" + (attachedSurface != null && attachedSurface.isValid()));
-            reconfiguring = false;
             return;
         }
         if (decoderActive && decoderWidth == pendingWidth && decoderHeight == pendingHeight) {
@@ -865,6 +879,10 @@ public class ReceiverCastService extends Service {
             videoDecoder.release();
             videoDecoder = VideoDecoderFactory.createDecoder();
         }
+        if (hasPendingConfig && phase == Phase.STREAMING) {
+            enterAwaitingKeyframe();
+            scheduleDecoderConfigureRetries();
+        }
     }
 
     private void updateStatus(String s) {
diff --git a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverPlaybackActivity.java b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverPlaybackActivity.java
index 3efa09f..fb4f0d6 100644
--- a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverPlaybackActivity.java
+++ b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverPlaybackActivity.java
@@ -73,7 +73,6 @@ public class ReceiverPlaybackActivity extends DrawerHostActivity {
     private boolean bound;
     private boolean autoStartListening;
     private boolean listeningCancelled;
-    private boolean autoPipAttempted;
 
     private final ICastStatusCallback.Stub statusCallback = new ICastStatusCallback.Stub() {
         @Override
@@ -249,7 +248,6 @@ public class ReceiverPlaybackActivity extends DrawerHostActivity {
         mainHandler.post(diagnosticsRefresh);
         updateDiagnosticsVisibility();
         updatePipUi();
-        maybeAutoEnterPip();
     }
 
     @Override
@@ -272,7 +270,6 @@ public class ReceiverPlaybackActivity extends DrawerHostActivity {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults);
         if (requestCode == PermissionHelper.REQUEST_RECEIVER_PLAYBACK) {
             updatePipUi();
-            maybeAutoEnterPip();
         }
     }
 
@@ -489,6 +486,9 @@ public class ReceiverPlaybackActivity extends DrawerHostActivity {
                         texture.setDefaultBufferSize(videoWidth, videoHeight);
                     }
                     applyTextureFitCenter();
+                    // Rotation often recreates the texture; re-bind decoder to the new Surface.
+                    surfaceSentToService = false;
+                    attachSurfaceIfReady();
                 }
 
                 @Override
@@ -562,32 +562,13 @@ public class ReceiverPlaybackActivity extends DrawerHostActivity {
         }
     }
 
+    /** Auto PiP when leaving the app during an active cast, not while waiting for a sender. */
     private boolean shouldAutoEnterPipOnLeave() {
         if (!AppPreferences.isReceiverPipEnabled(this)
                 || !PermissionHelper.hasReceiverPlaybackReady(this)) {
             return false;
         }
-        if (castSessionActive || streamRendering) {
-            return true;
-        }
-        return bound && awaitingOverlay != null
-                && awaitingOverlay.getVisibility() == View.VISIBLE;
-    }
-
-    private void maybeAutoEnterPip() {
-        if (!autoStartListening || autoPipAttempted || inPictureInPicture) {
-            return;
-        }
-        if (!AppPreferences.isReceiverPipEnabled(this)
-                || !PictureInPictureHelper.isSupported()) {
-            return;
-        }
-        if (!PermissionHelper.hasReceiverPlaybackReady(this)) {
-            PermissionHelper.remindForReceiverPlayback(this);
-            return;
-        }
-        autoPipAttempted = true;
-        mainHandler.post(() -> tryEnterPictureInPicture(false));
+        return castSessionActive || streamRendering;
     }
 
     private void tryEnterPictureInPicture(boolean userInitiated) {
diff --git a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverSession.java b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverSession.java
index eb634ea..9cb254f 100644
--- a/app/src/main/java/com/foxx/androidcast/receiver/ReceiverSession.java
+++ b/app/src/main/java/com/foxx/androidcast/receiver/ReceiverSession.java
@@ -54,6 +54,9 @@ public class ReceiverSession {
         /** TCP/UDP listen socket is bound; safe to advertise on the LAN. */
         void onListening();
 
+        /** About to accept a sender and run handshake (bind session stats before I/O). */
+        void onCastSessionStarting();
+
         void onNetworkAdviceApplied();
 
         void onPeerNetworkStats(NetworkStatsSnapshot stats);
@@ -157,6 +160,7 @@ public class ReceiverSession {
                     session = new CastSession(listenTransport);
                 }
                 inboundSessionGate.reset();
+                listener.onCastSessionStarting();
                 networkFeedback = new NetworkFeedbackManager(session, false);
                 if (networkFeedback.getPlane() instanceof PassThroughNetworkControlPlane) {
                     ((PassThroughNetworkControlPlane) networkFeedback.getPlane())
diff --git a/app/src/main/java/com/foxx/androidcast/sender/CastFanoutPump.java b/app/src/main/java/com/foxx/androidcast/sender/CastFanoutPump.java
index c7743c1..6d932c7 100644
--- a/app/src/main/java/com/foxx/androidcast/sender/CastFanoutPump.java
+++ b/app/src/main/java/com/foxx/androidcast/sender/CastFanoutPump.java
@@ -5,6 +5,7 @@ import android.util.Log;
 import com.foxx.androidcast.network.CastProtocol;
 import com.foxx.androidcast.network.CastSession;
 import com.foxx.androidcast.network.control.PassThroughNetworkControlPlane;
+import com.foxx.androidcast.stats.SessionStatsContext;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -53,6 +54,11 @@ public final class CastFanoutPump {
         return videoQueue.size() + audioQueue.size();
     }
 
+    /** Drops stale video frames (e.g. after capture resize / rotation). */
+    public void flushVideoQueue() {
+        videoQueue.clear();
+    }
+
     public void start(List<CastSession> sessionList, Runnable onSendFailed,
             PassThroughNetworkControlPlane statsPlane) {
         setSessions(sessionList);
@@ -144,7 +150,7 @@ public final class CastFanoutPump {
                     continue;
                 }
                 byte[] payload = item.buildPayload();
-                fanOut(item.type, payload);
+                fanOut(item.type, payload, item.keyFrame);
             } catch (InterruptedException e) {
                 if (!running.get()) {
                     break;
@@ -158,7 +164,9 @@ public final class CastFanoutPump {
         }
     }
 
-    private void fanOut(byte type, byte[] payload) {
+    private void fanOut(byte type, byte[] payload, boolean keyFrame) {
+        int payloadSize = payload != null ? payload.length : 0;
+        SessionStatsContext.recordOutboundMessage(type, keyFrame, payloadSize);
         int peer = 0;
         for (CastSession session : sessions) {
             peer++;
diff --git a/app/src/main/java/com/foxx/androidcast/sender/CastSendPump.java b/app/src/main/java/com/foxx/androidcast/sender/CastSendPump.java
index a7da65c..4231c10 100644
--- a/app/src/main/java/com/foxx/androidcast/sender/CastSendPump.java
+++ b/app/src/main/java/com/foxx/androidcast/sender/CastSendPump.java
@@ -5,6 +5,7 @@ import android.util.Log;
 import com.foxx.androidcast.network.CastProtocol;
 import com.foxx.androidcast.network.CastSession;
 import com.foxx.androidcast.network.control.PassThroughNetworkControlPlane;
+import com.foxx.androidcast.stats.SessionStatsContext;
 
 import java.io.IOException;
 import java.util.concurrent.LinkedBlockingQueue;
@@ -39,6 +40,11 @@ public final class CastSendPump {
         return videoQueue.size() + audioQueue.size();
     }
 
+    /** Drops stale video frames (e.g. after capture resize / rotation). */
+    public void flushVideoQueue() {
+        videoQueue.clear();
+    }
+
     public void start(CastSession session, Runnable onSendFailed) {
         start(session, onSendFailed, null);
     }
@@ -133,6 +139,8 @@ public final class CastSendPump {
                 }
                 byte[] payload = item.buildPayload();
                 session.send(item.type, payload);
+                int payloadSize = payload != null ? payload.length : 0;
+                SessionStatsContext.recordOutboundMessage(item.type, item.keyFrame, payloadSize);
                 if (statsPlane != null) {
                     statsPlane.recordSendBytes(payload.length + 5);
                 }
diff --git a/app/src/main/java/com/foxx/androidcast/sender/ScreenCastService.java b/app/src/main/java/com/foxx/androidcast/sender/ScreenCastService.java
index a54a462..60f62ed 100644
--- a/app/src/main/java/com/foxx/androidcast/sender/ScreenCastService.java
+++ b/app/src/main/java/com/foxx/androidcast/sender/ScreenCastService.java
@@ -47,6 +47,7 @@ import com.foxx.androidcast.media.codec.PassthroughCodecPolicy;
 import com.foxx.androidcast.media.codec.VideoCodecFactory;
 import com.foxx.androidcast.media.codec.VideoEncoderSink;
 import com.foxx.androidcast.media.codec.AudioEncoderSink;
+import com.foxx.androidcast.stats.SessionStatsContext;
 import com.foxx.androidcast.stats.SessionStatsRecorder;
 import com.foxx.androidcast.stats.SessionStatsStore;
 
@@ -240,6 +241,10 @@ public class ScreenCastService extends Service implements
                 }
             }));
             updateStatus(getString(R.string.connecting_to, host));
+            if (AppPreferences.isGrabSessionStats(this)) {
+                sessionStatsRecorder = new SessionStatsRecorder("send", settings.getTransport());
+                SessionStatsContext.bind(sessionStatsRecorder);
+            }
             multiCoordinator.connectAndHandshake(targets, settings, senderName, pin);
             List<MultiCastCoordinator.ActivePeer> peers = multiCoordinator.getPeers();
             if (peers.isEmpty()) {
@@ -267,7 +272,10 @@ public class ScreenCastService extends Service implements
             CastTrayNotifier.refresh(this);
             activeSettings = settings;
             if (AppPreferences.isGrabSessionStats(this)) {
-                sessionStatsRecorder = new SessionStatsRecorder("sender", settings.getTransport());
+                if (sessionStatsRecorder == null) {
+                    sessionStatsRecorder = new SessionStatsRecorder("send", settings.getTransport());
+                    SessionStatsContext.bind(sessionStatsRecorder);
+                }
                 sessionStatsRecorder.mergeSettings(settings);
                 sessionStatsRecorder.setClientCount(peers.size());
                 sessionStatsRecorder.setCodecs(settings.getNegotiatedVideoMime(), "AAC");
@@ -461,6 +469,11 @@ public class ScreenCastService extends Service implements
             videoEncoder.stop();
             videoEncoder = null;
         }
+        if (fanoutPump != null) {
+            fanoutPump.flushVideoQueue();
+        } else if (sendPump != null) {
+            sendPump.flushVideoQueue();
+        }
 
         captureWidth = size.width;
         captureHeight = size.height;
diff --git a/app/src/main/java/com/foxx/androidcast/stats/SessionEventJournal.java b/app/src/main/java/com/foxx/androidcast/stats/SessionEventJournal.java
new file mode 100644
index 0000000..6dd3e33
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/SessionEventJournal.java
@@ -0,0 +1,79 @@
+package com.foxx.androidcast.stats;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+/**
+ * Per-session event log ({@code send} or {@code recv} array only) with ~1 Hz {@code general} rollups.
+ */
+final class SessionEventJournal {
+  private static final long GENERAL_INTERVAL_MS = 1000L;
+  private static final int MAX_ENTRIES = 100_000;
+
+  private final long sessionStartMs;
+  private final JSONArray events = new JSONArray();
+  private long generalAccumulator;
+  private long lastGeneralFlushMs;
+
+  SessionEventJournal(long sessionStartMs) {
+    this.sessionStartMs = sessionStartMs;
+    lastGeneralFlushMs = sessionStartMs;
+  }
+
+  synchronized void record(String type, int size) {
+    if (type == null || size <= 0) {
+      return;
+    }
+    if (events.length() >= MAX_ENTRIES) {
+      return;
+    }
+    try {
+      JSONObject e = new JSONObject();
+      e.put("ts", System.currentTimeMillis() - sessionStartMs);
+      e.put("type", type);
+      e.put("size", size);
+      events.put(e);
+    } catch (Exception ignored) {
+    }
+  }
+
+  synchronized void addGeneralBytes(int wireBytes) {
+    if (wireBytes > 0) {
+      generalAccumulator += wireBytes;
+    }
+  }
+
+  synchronized void flushGeneralIfDue() {
+    long now = System.currentTimeMillis();
+    if (now - lastGeneralFlushMs < GENERAL_INTERVAL_MS) {
+      return;
+    }
+    flushGeneral(now);
+  }
+
+  synchronized void flushGeneralFinal() {
+    flushGeneral(System.currentTimeMillis());
+  }
+
+  private void flushGeneral(long now) {
+    if (events.length() >= MAX_ENTRIES) {
+      generalAccumulator = 0;
+      lastGeneralFlushMs = now;
+      return;
+    }
+    try {
+      JSONObject e = new JSONObject();
+      e.put("ts", now - sessionStartMs);
+      e.put("type", SessionStatsEventMapper.GENERAL);
+      e.put("size", generalAccumulator);
+      events.put(e);
+    } catch (Exception ignored) {
+    }
+    generalAccumulator = 0;
+    lastGeneralFlushMs = now;
+  }
+
+  synchronized JSONArray copyEvents() {
+    return events;
+  }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsContext.java b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsContext.java
new file mode 100644
index 0000000..be66f10
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsContext.java
@@ -0,0 +1,57 @@
+package com.foxx.androidcast.stats;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/** Active session stats recorder for transport/pump hooks without threading references everywhere. */
+public final class SessionStatsContext {
+  private static final AtomicReference<SessionStatsRecorder> ACTIVE = new AtomicReference<>();
+
+  private SessionStatsContext() {}
+
+  public static void bind(SessionStatsRecorder recorder) {
+    ACTIVE.set(recorder);
+  }
+
+  public static void unbind(SessionStatsRecorder recorder) {
+    ACTIVE.compareAndSet(recorder, null);
+  }
+
+  public static SessionStatsRecorder get() {
+    return ACTIVE.get();
+  }
+
+  public static void recordOutboundMessage(byte type, boolean keyFrame, int payloadBytes) {
+    SessionStatsRecorder r = ACTIVE.get();
+    if (r != null) {
+      r.recordOutboundMessage(type, keyFrame, payloadBytes);
+    }
+  }
+
+  public static void recordInboundMessage(byte type, boolean keyFrame, int payloadBytes) {
+    SessionStatsRecorder r = ACTIVE.get();
+    if (r != null) {
+      r.recordInboundMessage(type, keyFrame, payloadBytes);
+    }
+  }
+
+  public static void onDatagramSent(int wireBytes) {
+    SessionStatsRecorder r = ACTIVE.get();
+    if (r != null) {
+      r.onDatagramSent(wireBytes);
+    }
+  }
+
+  public static void onDatagramReceived(int wireBytes) {
+    SessionStatsRecorder r = ACTIVE.get();
+    if (r != null) {
+      r.onDatagramReceived(wireBytes);
+    }
+  }
+
+  public static void flushGeneralIfDue() {
+    SessionStatsRecorder r = ACTIVE.get();
+    if (r != null) {
+      r.flushGeneralIfDue();
+    }
+  }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsEventMapper.java b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsEventMapper.java
new file mode 100644
index 0000000..3f7760c
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsEventMapper.java
@@ -0,0 +1,44 @@
+package com.foxx.androidcast.stats;
+
+import com.foxx.androidcast.network.CastProtocol;
+
+/** Maps cast protocol message types to session journal event types. */
+public final class SessionStatsEventMapper {
+  public static final String KF = "kf";
+  public static final String VIDEO = "video";
+  public static final String AUDIO = "audio";
+  public static final String META = "meta";
+  public static final String SERVICE = "service";
+  public static final String UNKNOWN = "unknown";
+  public static final String GENERAL = "general";
+
+  private SessionStatsEventMapper() {}
+
+  /** Returns journal type for an app-layer message, or null if it should not be logged. */
+  public static String eventTypeForMessage(byte type, boolean keyFrame) {
+    switch (type) {
+      case CastProtocol.MSG_VIDEO_FRAME:
+        return keyFrame ? KF : VIDEO;
+      case CastProtocol.MSG_AUDIO_FRAME:
+        return AUDIO;
+      case CastProtocol.MSG_STREAM_CONFIG:
+      case CastProtocol.MSG_AUDIO_CONFIG:
+      case CastProtocol.MSG_NETWORK_STATS:
+      case CastProtocol.MSG_NETWORK_CONTROL:
+        return META;
+      case CastProtocol.MSG_HELLO:
+      case CastProtocol.MSG_AUTH:
+      case CastProtocol.MSG_AUTH_OK:
+      case CastProtocol.MSG_AUTH_FAIL:
+      case CastProtocol.MSG_CAST_SETTINGS:
+      case CastProtocol.MSG_RECEIVER_CAST_SETTINGS:
+      case CastProtocol.MSG_CODEC_CAPS:
+      case CastProtocol.MSG_CODEC_SELECTED:
+      case CastProtocol.MSG_GOODBYE:
+      case CastProtocol.MSG_AUDIO_CONSENT:
+        return SERVICE;
+      default:
+        return UNKNOWN;
+    }
+  }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsRecorder.java b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsRecorder.java
index c3e317f..596cede 100644
--- a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsRecorder.java
+++ b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsRecorder.java
@@ -16,8 +16,11 @@ import org.json.JSONObject;
  */
 public final class SessionStatsRecorder {
     private final long startedMs = System.currentTimeMillis();
+    /** {@code send} or {@code recv}. */
+    private final String direction;
     private final String role;
     private final String transport;
+    private final SessionEventJournal journal;
     private String videoCodec = "";
     private String audioCodec = "AAC";
     private String captureMode = "";
@@ -40,9 +43,56 @@ public final class SessionStatsRecorder {
     private final JSONArray samples = new JSONArray();
     private long lastSampleMs;
 
-    public SessionStatsRecorder(String role, String transport) {
-        this.role = role;
+    /** @param direction {@code send} or {@code recv}. */
+    public SessionStatsRecorder(String direction, String transport) {
+        this.direction = "recv".equals(direction) ? "recv" : "send";
+        this.role = "recv".equals(this.direction) ? "receiver" : "sender";
         this.transport = transport != null ? transport : "unknown";
+        this.journal = new SessionEventJournal(startedMs);
+    }
+
+    public String getDirection() {
+        return direction;
+    }
+
+    public boolean isSendDirection() {
+        return "send".equals(direction);
+    }
+
+    public void recordOutboundMessage(byte type, boolean keyFrame, int payloadBytes) {
+        if (!isSendDirection() || payloadBytes <= 0) {
+            return;
+        }
+        String eventType = SessionStatsEventMapper.eventTypeForMessage(type, keyFrame);
+        if (eventType != null) {
+            journal.record(eventType, payloadBytes);
+        }
+    }
+
+    public void recordInboundMessage(byte type, boolean keyFrame, int payloadBytes) {
+        if (isSendDirection() || payloadBytes <= 0) {
+            return;
+        }
+        String eventType = SessionStatsEventMapper.eventTypeForMessage(type, keyFrame);
+        if (eventType != null) {
+            journal.record(eventType, payloadBytes);
+        }
+    }
+
+    public void onDatagramSent(int wireBytes) {
+        if (isSendDirection()) {
+            journal.addGeneralBytes(wireBytes);
+        }
+    }
+
+    public void onDatagramReceived(int wireBytes) {
+        if (!isSendDirection()) {
+            journal.addGeneralBytes(wireBytes);
+        }
+    }
+
+    public void flushGeneralIfDue() {
+        journal.flushGeneralIfDue();
     }
 
     public void setClientCount(int count) {
@@ -80,6 +130,7 @@ public final class SessionStatsRecorder {
     }
 
     public void sampleNetwork(NetworkStatsSnapshot local, NetworkStatsSnapshot peer) {
+        flushGeneralIfDue();
         networkSamples++;
         NetworkStatsSnapshot s = local != null ? local : peer;
         if (s == null) {
@@ -130,7 +181,15 @@ public final class SessionStatsRecorder {
             lossTotals.recvVideoDecodeErrors = loss.recvVideoDecodeErrors;
             lossTotals.recvAudioDecodeErrors = loss.recvAudioDecodeErrors;
             lossTotals.recvAudioQueueDrops = loss.recvAudioQueueDrops;
+            lossTotals.recvDamagedVideoFrames = loss.recvDamagedVideoFrames;
             lossTotals.protectionMode = loss.protectionMode;
+            lossTotals.fecPacketsEncoded = loss.fecPacketsEncoded;
+            lossTotals.fecPacketsDecoded = loss.fecPacketsDecoded;
+            lossTotals.fecDecodeFailures = loss.fecDecodeFailures;
+            lossTotals.nackRequestsSent = loss.nackRequestsSent;
+            lossTotals.nackRequestsReceived = loss.nackRequestsReceived;
+            lossTotals.nackRetransmits = loss.nackRetransmits;
+            lossTotals.nackCacheMisses = loss.nackCacheMisses;
         }
     }
 
@@ -178,13 +237,16 @@ public final class SessionStatsRecorder {
     }
 
     public void finish(Context context) {
+        SessionStatsContext.unbind(this);
         if (!AppPreferences.isGrabSessionStats(context)) {
             return;
         }
+        journal.flushGeneralFinal();
         long endedMs = System.currentTimeMillis();
         try {
             JSONObject root = new JSONObject();
-            root.put("schema_version", 1);
+            root.put("schema_version", 2);
+            root.put("direction", direction);
             root.put("started_at_epoch_ms", startedMs);
             root.put("ended_at_epoch_ms", endedMs);
             root.put("duration_ms", endedMs - startedMs);
@@ -199,6 +261,11 @@ public final class SessionStatsRecorder {
             root.put("resolution", resolution);
             root.put("network_samples", networkSamples);
 
+            JSONArray journalEvents = journal.copyEvents();
+            if (journalEvents.length() > 0) {
+                root.put(direction, journalEvents);
+            }
+
             if (networkSamples > 0) {
                 root.put("avg_rtt_ms", sumRttMs / Math.max(1, networkSamples));
                 root.put("avg_loss_ratio", sumLossRatioMicro / (1_000_000.0 * Math.max(1, networkSamples)));
@@ -244,13 +311,20 @@ public final class SessionStatsRecorder {
                 udp.put("recv_audio_decode_errors", lossTotals.recvAudioDecodeErrors);
                 udp.put("recv_audio_queue_drops", lossTotals.recvAudioQueueDrops);
                 udp.put("recv_damaged_video_frames", lossTotals.recvDamagedVideoFrames);
+                udp.put("fec_packets_encoded", lossTotals.fecPacketsEncoded);
+                udp.put("fec_packets_decoded", lossTotals.fecPacketsDecoded);
+                udp.put("fec_decode_failures", lossTotals.fecDecodeFailures);
+                udp.put("nack_requests_sent", lossTotals.nackRequestsSent);
+                udp.put("nack_requests_received", lossTotals.nackRequestsReceived);
+                udp.put("nack_retransmits", lossTotals.nackRetransmits);
+                udp.put("nack_cache_misses", lossTotals.nackCacheMisses);
             }
             root.put("udp", udp);
             if (samples.length() > 0) {
                 root.put("samples", samples);
             }
 
-            SessionStatsStore.saveSession(context, startedMs, root);
+            SessionStatsStore.saveSession(context, startedMs, direction, root);
         } catch (Exception ignored) {
         }
     }
diff --git a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsStore.java b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsStore.java
index c0a4f24..e3a94d7 100644
--- a/app/src/main/java/com/foxx/androidcast/stats/SessionStatsStore.java
+++ b/app/src/main/java/com/foxx/androidcast/stats/SessionStatsStore.java
@@ -20,7 +20,10 @@ import java.util.Locale;
 /** Rotating flat JSON session logs in app-private storage. */
 public final class SessionStatsStore {
     private static final String DIR_NAME = "session_stats";
-    private static final String PREFIX = "session_";
+    /** Legacy captures before schema v2. */
+    private static final String PREFIX_LEGACY = "session_";
+    public static final String PREFIX_SEND = "session_send_";
+    public static final String PREFIX_RECV = "session_recv_";
     private static final String SUFFIX = ".json";
 
     private SessionStatsStore() {}
@@ -29,6 +32,31 @@ public final class SessionStatsStore {
         return new File(context.getApplicationContext().getFilesDir(), DIR_NAME);
     }
 
+    private static boolean isSessionJson(String name) {
+        if (!name.endsWith(SUFFIX)) {
+            return false;
+        }
+        return name.startsWith(PREFIX_LEGACY)
+                || name.startsWith(PREFIX_SEND)
+                || name.startsWith(PREFIX_RECV);
+    }
+
+    /** Session JSON files, newest first (by filename / start time). */
+    public static List<File> listSessionFiles(Context context) {
+        File dir = statsDir(context);
+        if (!dir.exists()) {
+            return Collections.emptyList();
+        }
+        File[] files = dir.listFiles((d, name) -> isSessionJson(name));
+        if (files == null || files.length == 0) {
+            return Collections.emptyList();
+        }
+        List<File> list = new ArrayList<>();
+        Collections.addAll(list, files);
+        Collections.sort(list, (a, b) -> b.getName().compareTo(a.getName()));
+        return list;
+    }
+
     /** Keep at most {@link CastConfig#SESSION_STATS_MAX_FILES} - 1 files before a new session. */
     public static void pruneOnAppStart(Context context) {
         pruneDirectory(statsDir(context), CastConfig.SESSION_STATS_MAX_FILES);
@@ -39,7 +67,7 @@ public final class SessionStatsStore {
         if (dir == null || !dir.exists()) {
             return;
         }
-        File[] files = dir.listFiles((d, name) -> name.startsWith(PREFIX) && name.endsWith(SUFFIX));
+        File[] files = dir.listFiles((d, name) -> isSessionJson(name));
         if (files == null || files.length == 0) {
             return;
         }
@@ -54,12 +82,14 @@ public final class SessionStatsStore {
         }
     }
 
-    public static void saveSession(Context context, long startedMs, JSONObject json) throws Exception {
+    public static void saveSession(Context context, long startedMs, String direction, JSONObject json)
+            throws Exception {
         File dir = statsDir(context);
         if (!dir.exists() && !dir.mkdirs()) {
             throw new IllegalStateException("Cannot create session_stats dir");
         }
-        String name = PREFIX + formatTimestamp(startedMs) + SUFFIX;
+        String prefix = prefixForDirection(direction);
+        String name = prefix + formatTimestamp(startedMs) + SUFFIX;
         File out = new File(dir, name);
         byte[] bytes = json.toString(2).getBytes(StandardCharsets.UTF_8);
         try (FileOutputStream fos = new FileOutputStream(out)) {
@@ -67,6 +97,13 @@ public final class SessionStatsStore {
         }
     }
 
+    static String prefixForDirection(String direction) {
+        if ("recv".equals(direction)) {
+            return PREFIX_RECV;
+        }
+        return PREFIX_SEND;
+    }
+
     private static String formatTimestamp(long epochMs) {
         return new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(new Date(epochMs));
     }
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/ChartTickHelper.java b/app/src/main/java/com/foxx/androidcast/stats/ui/ChartTickHelper.java
new file mode 100644
index 0000000..61d55fd
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/ChartTickHelper.java
@@ -0,0 +1,79 @@
+package com.foxx.androidcast.stats.ui;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/** Nice axis ticks for session charts. */
+final class ChartTickHelper {
+    private ChartTickHelper() {}
+
+    static final class Tick {
+        final double value;
+        final String label;
+
+        Tick(double value, String label) {
+            this.value = value;
+            this.label = label;
+        }
+    }
+
+    static List<Tick> linear(double min, double max, int maxTicks) {
+        List<Tick> out = new ArrayList<>();
+        if (!Double.isFinite(min) || !Double.isFinite(max) || max <= min) {
+            return out;
+        }
+        double step = niceStep(max - min, maxTicks);
+        double start = Math.ceil(min / step) * step;
+        for (double v = start; v <= max + step * 0.001; v += step) {
+            out.add(new Tick(v, formatValue(v, step)));
+        }
+        return out;
+    }
+
+    static List<Tick> timeMs(long minMs, long maxMs, int maxTicks) {
+        List<Tick> out = new ArrayList<>();
+        if (maxMs <= minMs) {
+            return out;
+        }
+        double range = maxMs - minMs;
+        double step = niceStep(range, maxTicks);
+        double start = Math.ceil(minMs / step) * step;
+        for (double v = start; v <= maxMs + step * 0.001; v += step) {
+            long ms = Math.round(v);
+            out.add(new Tick(ms, formatTimeMs(ms)));
+        }
+        return out;
+    }
+
+    private static double niceStep(double range, int maxTicks) {
+        double raw = range / Math.max(2, maxTicks);
+        if (raw <= 0) {
+            return 1;
+        }
+        double mag = Math.pow(10, Math.floor(Math.log10(raw)));
+        double norm = raw / mag;
+        double nice = norm <= 1 ? 1 : norm <= 2 ? 2 : norm <= 5 ? 5 : 10;
+        return nice * mag;
+    }
+
+    private static String formatValue(double v, double step) {
+        if (step >= 1) {
+            return String.format(Locale.US, "%.0f", v);
+        }
+        if (step >= 0.1) {
+            return String.format(Locale.US, "%.1f", v);
+        }
+        return String.format(Locale.US, "%.2f", v);
+    }
+
+    private static String formatTimeMs(long ms) {
+        if (ms >= 60_000) {
+            return String.format(Locale.US, "%.1fm", ms / 60_000.0);
+        }
+        if (ms >= 1000) {
+            return String.format(Locale.US, "%.1fs", ms / 1000.0);
+        }
+        return ms + "ms";
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionBarChartView.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionBarChartView.java
new file mode 100644
index 0000000..776cae9
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionBarChartView.java
@@ -0,0 +1,110 @@
+package com.foxx.androidcast.stats.ui;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.util.AttributeSet;
+import android.view.View;
+
+import androidx.annotation.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/** Horizontal bar chart for UDP / protection counter summaries. */
+public class SessionBarChartView extends View {
+    private static final class Bar {
+        final String label;
+        final long value;
+        final int color;
+
+        Bar(String label, long value, int color) {
+            this.label = label;
+            this.value = value;
+            this.color = color;
+        }
+    }
+
+    private final Paint barPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint labelPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final List<Bar> bars = new ArrayList<>();
+
+    public SessionBarChartView(Context context) {
+        super(context);
+        init();
+    }
+
+    public SessionBarChartView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+    private void init() {
+        textPaint.setColor(0xFFEEEEEE);
+        textPaint.setTextSize(24f);
+        labelPaint.setColor(0xFFAAAAAA);
+        labelPaint.setTextSize(22f);
+    }
+
+    public void setSession(@Nullable SessionRecord session) {
+        bars.clear();
+        if (session != null) {
+            SessionRecord.UdpStats u = session.udp;
+            addBar("UDP tx", u.datagramsTx, 0xFF64B5F6);
+            addBar("UDP rx", u.datagramsRx, 0xFF42A5F5);
+            addBar("Reasm OK", u.reassemblyOk, 0xFF81C784);
+            addBar("Reasm lost", u.reassemblyLost, 0xFFFF8A65);
+            addBar("Wire drop", u.wireDropped, 0xFFE57373);
+            addBar("Vid dec err", u.recvVideoDecodeErrors, 0xFFFF5252);
+            SessionRecord.ProtectionStats p = session.protection;
+            addBar("FEC enc", p.fecEncoded, 0xFFBA68C8);
+            addBar("FEC dec", p.fecDecoded, 0xFFAB47BC);
+            addBar("NACK rtx", p.nackRetransmits, 0xFFFFD54F);
+        }
+        requestLayout();
+        invalidate();
+    }
+
+    private void addBar(String label, long value, int color) {
+        if (value > 0) {
+            bars.add(new Bar(label, value, color));
+        }
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        int h = bars.isEmpty() ? 80 : Math.max(120, bars.size() * 36 + 24);
+        setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), h);
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        if (bars.isEmpty()) {
+            labelPaint.setTextSize(26f);
+            canvas.drawText("No counter data", 24f, 48f, labelPaint);
+            return;
+        }
+        long max = 1L;
+        for (Bar b : bars) {
+            max = Math.max(max, b.value);
+        }
+        float rowH = 32f;
+        float y = 12f;
+        float labelW = 140f;
+        float barLeft = labelW + 16f;
+        float barMaxW = getWidth() - barLeft - 80f;
+        for (Bar b : bars) {
+            labelPaint.setColor(0xFFAAAAAA);
+            canvas.drawText(b.label, 8f, y + 22f, labelPaint);
+            float bw = barMaxW * (b.value / (float) max);
+            barPaint.setColor(b.color);
+            canvas.drawRect(barLeft, y + 4f, barLeft + bw, y + 28f, barPaint);
+            textPaint.setColor(0xFFEEEEEE);
+            canvas.drawText(String.format(Locale.US, "%d", b.value), barLeft + bw + 8f, y + 22f, textPaint);
+            y += rowH;
+        }
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionLineChartView.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionLineChartView.java
new file mode 100644
index 0000000..d19dcdb
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionLineChartView.java
@@ -0,0 +1,481 @@
+package com.foxx.androidcast.stats.ui;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.Typeface;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.ScaleGestureDetector;
+import android.view.View;
+
+import androidx.annotation.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Multi-session line chart with zoom, grid, legend, and hover marker + tooltip.
+ */
+public class SessionLineChartView extends View {
+    public enum Metric {
+        BITRATE("Video bitrate (kbps)"),
+        LOSS("Packet loss (%)"),
+        ENCODE_FPS("Encode FPS");
+
+        final String axisLabel;
+
+        Metric(String axisLabel) {
+            this.axisLabel = axisLabel;
+        }
+    }
+
+    private static final int[] SESSION_COLORS = {
+            0xFF64B5F6, 0xFFFF8A65, 0xFF81C784, 0xFFFFD54F, 0xFFBA68C8, 0xFF4DD0E1
+    };
+
+    private static final float PAD_LEFT = 72f;
+    private static final float PAD_RIGHT = 16f;
+    private static final float PAD_TOP = 16f;
+    private static final float PAD_BOTTOM = 48f;
+
+    private final Paint gridPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint axisPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint legendBgPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint legendBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint swatchPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint markerFill = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint markerStroke = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint tooltipBg = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint tooltipFg = new Paint(Paint.ANTI_ALIAS_FLAG);
+
+    private final List<SessionRecord> sessions = new ArrayList<>();
+    private Metric metric = Metric.BITRATE;
+    private final ScaleGestureDetector scaleDetector;
+
+    private double viewMinT;
+    private double viewMaxT = 1;
+    private double viewMinY;
+    private double viewMaxY = 1;
+
+    private float hoverX = -1;
+    private float hoverY = -1;
+    private int hoverSessionIndex = -1;
+    private SessionRecord.SamplePoint hoverPoint;
+    private float hoverPlotX;
+    private float hoverPlotY;
+
+    public SessionLineChartView(Context context) {
+        super(context);
+        scaleDetector = new ScaleGestureDetector(context, new ScaleListener());
+        initPaints();
+    }
+
+    public SessionLineChartView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        scaleDetector = new ScaleGestureDetector(context, new ScaleListener());
+        initPaints();
+    }
+
+    private void initPaints() {
+        gridPaint.setColor(0xFF3A3A3A);
+        gridPaint.setStrokeWidth(1f);
+        axisPaint.setColor(0xFFAAAAAA);
+        axisPaint.setStrokeWidth(2f);
+        linePaint.setStyle(Paint.Style.STROKE);
+        linePaint.setStrokeWidth(3f);
+        textPaint.setColor(0xFFBBBBBB);
+        textPaint.setTextSize(22f);
+        legendBgPaint.setColor(0xB8000000);
+        legendBorderPaint.setColor(0xFF888888);
+        legendBorderPaint.setStyle(Paint.Style.STROKE);
+        legendBorderPaint.setStrokeWidth(1f);
+        swatchPaint.setStyle(Paint.Style.FILL);
+        markerFill.setStyle(Paint.Style.FILL);
+        markerStroke.setStyle(Paint.Style.STROKE);
+        markerStroke.setColor(0xFFFFFFFF);
+        markerStroke.setStrokeWidth(2f);
+        tooltipBg.setColor(0xE0000000);
+        tooltipFg.setColor(0xFFFFFFFF);
+        tooltipFg.setTextSize(24f);
+    }
+
+    public void setSessions(@Nullable List<SessionRecord> records, Metric metric) {
+        sessions.clear();
+        if (records != null) {
+            sessions.addAll(records);
+        }
+        this.metric = metric != null ? metric : Metric.BITRATE;
+        resetView();
+        clearHover();
+        invalidate();
+    }
+
+    private void resetView() {
+        viewMinT = 0;
+        viewMaxT = Math.max(1, dataMaxTimeMs());
+        double[] y = dataYRange();
+        viewMinY = y[0];
+        viewMaxY = y[1];
+    }
+
+    private long dataMaxTimeMs() {
+        long max = 1;
+        for (SessionRecord doc : sessions) {
+            for (SessionRecord.SamplePoint p : doc.samples) {
+                max = Math.max(max, p.tMs);
+            }
+            max = Math.max(max, doc.durationMs);
+        }
+        return max;
+    }
+
+    private double[] dataYRange() {
+        double min = Double.POSITIVE_INFINITY;
+        double max = Double.NEGATIVE_INFINITY;
+        for (SessionRecord doc : sessions) {
+            for (SessionRecord.SamplePoint p : doc.samples) {
+                double v = metricValue(p);
+                if (Double.isFinite(v)) {
+                    min = Math.min(min, v);
+                    max = Math.max(max, v);
+                }
+            }
+        }
+        if (!Double.isFinite(min)) {
+            return new double[] {0, 1};
+        }
+        if (max <= min) {
+            max = min + 1;
+        }
+        double pad = (max - min) * 0.06;
+        return new double[] {min - pad, max + pad};
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        scaleDetector.onTouchEvent(event);
+        int action = event.getActionMasked();
+        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_MOVE) {
+            hoverX = event.getX();
+            hoverY = event.getY();
+            updateHoverHit();
+            invalidate();
+            return true;
+        }
+        if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
+            clearHover();
+            return true;
+        }
+        return super.onTouchEvent(event);
+    }
+
+    @Override
+    public boolean onGenericMotionEvent(MotionEvent event) {
+        if ((event.getSource() & android.view.InputDevice.SOURCE_CLASS_POINTER) != 0
+                && event.getAction() == MotionEvent.ACTION_SCROLL) {
+            float factor = event.getAxisValue(MotionEvent.AXIS_VSCROLL) > 0 ? 0.85f : 1.18f;
+            zoomAt(event.getX(), event.getY(), factor);
+            invalidate();
+            return true;
+        }
+        return super.onGenericMotionEvent(event);
+    }
+
+    private void zoomAt(float mx, float my, float factor) {
+        float plotW = plotWidth();
+        float plotH = plotHeight();
+        if (plotW <= 0 || plotH <= 0) {
+            return;
+        }
+        if (mx >= PAD_LEFT && mx <= PAD_LEFT + plotW && my >= PAD_TOP && my <= PAD_TOP + plotH) {
+            double relX = (mx - PAD_LEFT) / plotW;
+            double relY = 1.0 - (my - PAD_TOP) / plotH;
+            zoomTime(viewMinT + relX * (viewMaxT - viewMinT), factor);
+            zoomY(viewMinY + relY * (viewMaxY - viewMinY), factor);
+        } else {
+            zoomTime((viewMinT + viewMaxT) / 2, factor);
+            zoomY((viewMinY + viewMaxY) / 2, factor);
+        }
+    }
+
+    private void zoomTime(double anchor, float factor) {
+        double span = viewMaxT - viewMinT;
+        if (span <= 0) {
+            return;
+        }
+        double newSpan = Math.max(50, span * factor);
+        viewMinT = anchor - (anchor - viewMinT) * (newSpan / span);
+        viewMaxT = viewMinT + newSpan;
+    }
+
+    private void zoomY(double anchor, float factor) {
+        double span = viewMaxY - viewMinY;
+        if (span <= 0) {
+            return;
+        }
+        double newSpan = Math.max(1, span * factor);
+        viewMinY = anchor - (anchor - viewMinY) * (newSpan / span);
+        viewMaxY = viewMinY + newSpan;
+    }
+
+    private void clearHover() {
+        hoverX = -1;
+        hoverY = -1;
+        hoverSessionIndex = -1;
+        hoverPoint = null;
+        invalidate();
+    }
+
+    private void updateHoverHit() {
+        hoverSessionIndex = -1;
+        hoverPoint = null;
+        float plotW = plotWidth();
+        float plotH = plotHeight();
+        if (plotW <= 0 || plotH <= 0 || sessions.isEmpty()) {
+            return;
+        }
+        if (hoverX < PAD_LEFT || hoverX > PAD_LEFT + plotW
+                || hoverY < PAD_TOP || hoverY > PAD_TOP + plotH) {
+            return;
+        }
+        double best = 48;
+        for (int si = 0; si < sessions.size(); si++) {
+            for (SessionRecord.SamplePoint p : sessions.get(si).samples) {
+                if (p.tMs < viewMinT || p.tMs > viewMaxT) {
+                    continue;
+                }
+                double v = metricValue(p);
+                if (v < viewMinY || v > viewMaxY) {
+                    continue;
+                }
+                float x = toScreenX(p.tMs);
+                float y = toScreenY(v);
+                double d = Math.hypot(hoverX - x, hoverY - y);
+                if (d < best) {
+                    best = d;
+                    hoverSessionIndex = si;
+                    hoverPoint = p;
+                    hoverPlotX = x;
+                    hoverPlotY = y;
+                }
+            }
+        }
+    }
+
+    private float plotWidth() {
+        return Math.max(0, getWidth() - PAD_LEFT - PAD_RIGHT);
+    }
+
+    private float plotHeight() {
+        return Math.max(0, getHeight() - PAD_TOP - PAD_BOTTOM);
+    }
+
+    private float toScreenX(double tMs) {
+        float plotW = plotWidth();
+        double span = viewMaxT - viewMinT;
+        if (span <= 0) {
+            return PAD_LEFT;
+        }
+        return PAD_LEFT + (float) (((tMs - viewMinT) / span) * plotW);
+    }
+
+    private float toScreenY(double v) {
+        float plotH = plotHeight();
+        double span = viewMaxY - viewMinY;
+        if (span <= 0) {
+            return PAD_TOP + plotH;
+        }
+        return PAD_TOP + plotH - (float) (((v - viewMinY) / span) * plotH);
+    }
+
+    private double metricValue(SessionRecord.SamplePoint p) {
+        switch (metric) {
+            case LOSS:
+                return p.lossRatio * 100.0;
+            case ENCODE_FPS:
+                return p.encodeFps;
+            case BITRATE:
+            default:
+                return p.videoBitrateKbps > 0 ? p.videoBitrateKbps : p.targetBitrateKbps;
+        }
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        canvas.drawColor(0xFF121212);
+        if (sessions.isEmpty() || !hasPlottableData()) {
+            textPaint.setTextSize(28f);
+            canvas.drawText(sessions.isEmpty() ? "Select session(s)" : "No time-series samples",
+                    PAD_LEFT, PAD_TOP + 32f, textPaint);
+            return;
+        }
+
+        float plotW = plotWidth();
+        float plotH = plotHeight();
+        if (plotW <= 1 || plotH <= 1) {
+            return;
+        }
+
+        List<ChartTickHelper.Tick> xTicks = ChartTickHelper.timeMs(
+                (long) viewMinT, (long) viewMaxT, 7);
+        List<ChartTickHelper.Tick> yTicks = ChartTickHelper.linear(viewMinY, viewMaxY, 5);
+
+        for (ChartTickHelper.Tick t : xTicks) {
+            float x = toScreenX(t.value);
+            canvas.drawLine(x, PAD_TOP, x, PAD_TOP + plotH, gridPaint);
+        }
+        for (ChartTickHelper.Tick t : yTicks) {
+            float y = toScreenY(t.value);
+            canvas.drawLine(PAD_LEFT, y, PAD_LEFT + plotW, y, gridPaint);
+        }
+
+        canvas.drawLine(PAD_LEFT, PAD_TOP + plotH, PAD_LEFT + plotW, PAD_TOP + plotH, axisPaint);
+        canvas.drawLine(PAD_LEFT, PAD_TOP, PAD_LEFT, PAD_TOP + plotH, axisPaint);
+
+        textPaint.setTextSize(20f);
+        textPaint.setColor(0xFFAAAAAA);
+        for (ChartTickHelper.Tick t : xTicks) {
+            float x = toScreenX(t.value);
+            canvas.drawText(t.label, x - 20f, PAD_TOP + plotH + 32f, textPaint);
+        }
+        for (ChartTickHelper.Tick t : yTicks) {
+            float y = toScreenY(t.value);
+            canvas.drawText(t.label, 4f, y + 6f, textPaint);
+        }
+
+        for (int si = 0; si < sessions.size(); si++) {
+            SessionRecord doc = sessions.get(si);
+            if (doc.samples.size() < 2) {
+                continue;
+            }
+            linePaint.setColor(SESSION_COLORS[si % SESSION_COLORS.length]);
+            drawSessionLine(canvas, doc);
+        }
+
+        drawLegend(canvas, plotW);
+
+        if (hoverPoint != null && hoverSessionIndex >= 0) {
+            int color = SESSION_COLORS[hoverSessionIndex % SESSION_COLORS.length];
+            markerFill.setColor(color);
+            canvas.drawCircle(hoverPlotX, hoverPlotY, 8f, markerFill);
+            canvas.drawCircle(hoverPlotX, hoverPlotY, 8f, markerStroke);
+            drawHoverPopup(canvas, color);
+        }
+    }
+
+    private boolean hasPlottableData() {
+        for (SessionRecord doc : sessions) {
+            if (doc.samples.size() >= 2) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void drawSessionLine(Canvas canvas, SessionRecord doc) {
+        Path path = new Path();
+        boolean first = true;
+        for (SessionRecord.SamplePoint p : doc.samples) {
+            if (p.tMs < viewMinT || p.tMs > viewMaxT) {
+                continue;
+            }
+            double v = metricValue(p);
+            if (v < viewMinY || v > viewMaxY) {
+                continue;
+            }
+            float x = toScreenX(p.tMs);
+            float y = toScreenY(v);
+            if (first) {
+                path.moveTo(x, y);
+                first = false;
+            } else {
+                path.lineTo(x, y);
+            }
+        }
+        canvas.drawPath(path, linePaint);
+    }
+
+    private void drawLegend(Canvas canvas, float plotW) {
+        int rows = 0;
+        for (SessionRecord doc : sessions) {
+            if (doc.samples.size() >= 2) {
+                rows++;
+            }
+        }
+        if (rows == 0) {
+            return;
+        }
+        float legendW = 280f;
+        float rowH = 28f;
+        float legendH = rows * rowH + 16f;
+        float x0 = PAD_LEFT + plotW - legendW - 8f;
+        float y0 = PAD_TOP + 8f;
+        canvas.drawRoundRect(x0, y0, x0 + legendW, y0 + legendH, 8f, 8f, legendBgPaint);
+        canvas.drawRoundRect(x0, y0, x0 + legendW, y0 + legendH, 8f, 8f, legendBorderPaint);
+
+        int row = 0;
+        for (int si = 0; si < sessions.size(); si++) {
+            SessionRecord doc = sessions.get(si);
+            if (doc.samples.size() < 2) {
+                continue;
+            }
+            int color = SESSION_COLORS[si % SESSION_COLORS.length];
+            float ry = y0 + 8f + row * rowH;
+            swatchPaint.setColor(color);
+            canvas.drawRoundRect(x0 + 10f, ry, x0 + 28f, ry + 16f, 3f, 3f, swatchPaint);
+            legendBorderPaint.setStyle(Paint.Style.STROKE);
+            canvas.drawRoundRect(x0 + 10f, ry, x0 + 28f, ry + 16f, 3f, 3f, legendBorderPaint);
+            textPaint.setColor(0xFFFFFFFF);
+            textPaint.setTextSize(20f);
+            textPaint.setTypeface(si == hoverSessionIndex ? Typeface.DEFAULT_BOLD : Typeface.DEFAULT);
+            String name = doc.fileName;
+            if (name.length() > 32) {
+                name = "…" + name.substring(name.length() - 31);
+            }
+            canvas.drawText(name, x0 + 36f, ry + 14f, textPaint);
+            row++;
+        }
+        textPaint.setTypeface(Typeface.DEFAULT);
+    }
+
+    private void drawHoverPopup(Canvas canvas, int accentColor) {
+        String text = String.format(Locale.US,
+                "t=%d ms  bitrate=%.0f kbps  loss=%.2f%%  fps=%.1f",
+                hoverPoint.tMs,
+                hoverPoint.videoBitrateKbps,
+                hoverPoint.lossRatio * 100.0,
+                hoverPoint.encodeFps);
+        float tw = tooltipFg.measureText(text) + 24f;
+        float th = 36f;
+        float px = hoverPlotX + 14f;
+        float py = hoverPlotY - th - 16f;
+        if (px + tw > PAD_LEFT + plotWidth()) {
+            px = hoverPlotX - tw - 14f;
+        }
+        if (py < PAD_TOP) {
+            py = hoverPlotY + 14f;
+        }
+        tooltipBg.setColor(0xE0000000);
+        canvas.drawRoundRect(px, py, px + tw, py + th, 8f, 8f, tooltipBg);
+        markerStroke.setColor(accentColor);
+        canvas.drawRoundRect(px, py, px + tw, py + th, 8f, 8f, markerStroke);
+        markerStroke.setColor(0xFFFFFFFF);
+        canvas.drawText(text, px + 12f, py + 24f, tooltipFg);
+    }
+
+    private final class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
+        @Override
+        public boolean onScale(ScaleGestureDetector detector) {
+            float factor = 1f / detector.getScaleFactor();
+            zoomAt(detector.getFocusX(), detector.getFocusY(), factor);
+            invalidate();
+            return true;
+        }
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionRecord.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionRecord.java
new file mode 100644
index 0000000..8eabefb
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionRecord.java
@@ -0,0 +1,228 @@
+package com.foxx.androidcast.stats.ui;
+
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/** Parsed session JSON for the in-app statistics analyzer. */
+public final class SessionRecord {
+    public final String fileName;
+    public final int schemaVersion;
+    public final long startedAtEpochMs;
+    public final long endedAtEpochMs;
+    public final long durationMs;
+    /** {@code send} or {@code recv}; inferred from filename when absent. */
+    public final String direction;
+    public final String role;
+    public final String transport;
+    public final int clientCount;
+    public final int disruptCount;
+    public final int idleTimeoutCount;
+    public final String videoCodec;
+    public final String audioCodec;
+    public final String captureMode;
+    public final String resolution;
+    public final int networkSamples;
+    public final long avgRttMs;
+    public final double avgLossRatio;
+    public final long avgVideoBitrateKbps;
+    public final double avgEncodeFps;
+    public final ProtectionStats protection;
+    public final UdpStats udp;
+    public final List<SamplePoint> samples;
+
+    public SessionRecord(String fileName, JSONObject root) {
+        this.fileName = fileName;
+        schemaVersion = root.optInt("schema_version", 0);
+        startedAtEpochMs = root.optLong("started_at_epoch_ms", 0L);
+        endedAtEpochMs = root.optLong("ended_at_epoch_ms", 0L);
+        durationMs = root.optLong("duration_ms", 0L);
+        direction = inferDirection(fileName, root);
+        role = root.optString("role", direction.equals("recv") ? "receiver" : "sender");
+        transport = root.optString("transport", "?");
+        clientCount = root.optInt("client_count", 1);
+        disruptCount = root.optInt("disrupt_count", 0);
+        idleTimeoutCount = root.optInt("idle_timeout_count", 0);
+        videoCodec = root.optString("video_codec", "");
+        audioCodec = root.optString("audio_codec", "");
+        captureMode = root.optString("capture_mode", "");
+        resolution = root.optString("resolution", "");
+        networkSamples = root.optInt("network_samples", 0);
+        avgRttMs = root.optLong("avg_rtt_ms", 0L);
+        avgLossRatio = root.optDouble("avg_loss_ratio", 0.0);
+        avgVideoBitrateKbps = root.optLong("avg_video_bitrate_kbps", 0L);
+        avgEncodeFps = root.optDouble("avg_encode_fps", 0.0);
+        protection = ProtectionStats.fromJson(root.optJSONObject("stream_protection"));
+        udp = UdpStats.fromJson(root.optJSONObject("udp"));
+        samples = SamplePoint.parseArray(root.optJSONArray("samples"));
+    }
+
+    public boolean hasTimeSeries() {
+        return samples.size() >= 2;
+    }
+
+    public String listSubtitle() {
+        long min = durationMs / 60_000L;
+        long sec = (durationMs / 1000L) % 60L;
+        return direction + " · " + transport + " · " + min + "m " + sec + "s";
+    }
+
+    private static String inferDirection(String fileName, JSONObject root) {
+        String d = root.optString("direction", "");
+        if ("send".equals(d) || "recv".equals(d)) {
+            return d;
+        }
+        if (fileName != null) {
+            if (fileName.startsWith("session_send_")) {
+                return "send";
+            }
+            if (fileName.startsWith("session_recv_")) {
+                return "recv";
+            }
+        }
+        String role = root.optString("role", "");
+        return "receiver".equals(role) ? "recv" : "send";
+    }
+
+    public static final class SamplePoint {
+        public final long tMs;
+        public final double videoBitrateKbps;
+        public final int rttMs;
+        public final double lossRatio;
+        public final double encodeFps;
+        public final int targetBitrateKbps;
+        public final int congestionLevel;
+
+        public SamplePoint(long tMs, double videoBitrateKbps, int rttMs, double lossRatio,
+                double encodeFps, int targetBitrateKbps, int congestionLevel) {
+            this.tMs = tMs;
+            this.videoBitrateKbps = videoBitrateKbps;
+            this.rttMs = rttMs;
+            this.lossRatio = lossRatio;
+            this.encodeFps = encodeFps;
+            this.targetBitrateKbps = targetBitrateKbps;
+            this.congestionLevel = congestionLevel;
+        }
+
+        static SamplePoint fromJson(JSONObject o) {
+            return new SamplePoint(
+                    o.optLong("t_ms", 0L),
+                    o.optDouble("video_bitrate_kbps", 0.0),
+                    o.optInt("rtt_ms", 0),
+                    o.optDouble("loss_ratio", 0.0),
+                    o.optDouble("encode_fps", 0.0),
+                    o.optInt("target_bitrate_kbps", 0),
+                    o.optInt("congestion_level", 0));
+        }
+
+        static List<SamplePoint> parseArray(org.json.JSONArray arr) {
+            if (arr == null || arr.length() == 0) {
+                return Collections.emptyList();
+            }
+            List<SamplePoint> out = new ArrayList<>(arr.length());
+            for (int i = 0; i < arr.length(); i++) {
+                JSONObject o = arr.optJSONObject(i);
+                if (o != null) {
+                    out.add(fromJson(o));
+                }
+            }
+            return out;
+        }
+    }
+
+    public static final class ProtectionStats {
+        public final String mode;
+        public final boolean fecEnabled;
+        public final boolean nackEnabled;
+        public final long fecEncoded;
+        public final long fecDecoded;
+        public final long fecDecodeFailures;
+        public final long nackSent;
+        public final long nackReceived;
+        public final long nackRetransmits;
+
+        ProtectionStats(String mode, boolean fecEnabled, boolean nackEnabled, long fecEncoded,
+                long fecDecoded, long fecDecodeFailures, long nackSent, long nackReceived,
+                long nackRetransmits) {
+            this.mode = mode != null ? mode : "NONE";
+            this.fecEnabled = fecEnabled;
+            this.nackEnabled = nackEnabled;
+            this.fecEncoded = fecEncoded;
+            this.fecDecoded = fecDecoded;
+            this.fecDecodeFailures = fecDecodeFailures;
+            this.nackSent = nackSent;
+            this.nackReceived = nackReceived;
+            this.nackRetransmits = nackRetransmits;
+        }
+
+        static ProtectionStats fromJson(JSONObject o) {
+            if (o == null) {
+                return new ProtectionStats("NONE", false, false, 0, 0, 0, 0, 0, 0);
+            }
+            return new ProtectionStats(
+                    o.optString("mode", "NONE"),
+                    o.optBoolean("fec_enabled", false),
+                    o.optBoolean("nack_enabled", false),
+                    o.optLong("fec_packets_encoded", 0L),
+                    o.optLong("fec_packets_decoded", 0L),
+                    o.optLong("fec_decode_failures", 0L),
+                    o.optLong("nack_requests_sent", 0L),
+                    o.optLong("nack_requests_received", 0L),
+                    o.optLong("nack_retransmits", 0L));
+        }
+    }
+
+    public static final class UdpStats {
+        public final long datagramsTx;
+        public final long datagramsRx;
+        public final long datagramsInvalid;
+        public final long fragmentsRx;
+        public final long fragmentsDuplicate;
+        public final long reassemblyOk;
+        public final long reassemblyLost;
+        public final long wireDropped;
+        public final long malformed;
+        public final long sendDroppedVideoP;
+        public final long recvVideoDecodeErrors;
+        public final long recvDamagedVideoFrames;
+
+        UdpStats(long datagramsTx, long datagramsRx, long datagramsInvalid, long fragmentsRx,
+                long fragmentsDuplicate, long reassemblyOk, long reassemblyLost, long wireDropped,
+                long malformed, long sendDroppedVideoP, long recvVideoDecodeErrors,
+                long recvDamagedVideoFrames) {
+            this.datagramsTx = datagramsTx;
+            this.datagramsRx = datagramsRx;
+            this.datagramsInvalid = datagramsInvalid;
+            this.fragmentsRx = fragmentsRx;
+            this.fragmentsDuplicate = fragmentsDuplicate;
+            this.reassemblyOk = reassemblyOk;
+            this.reassemblyLost = reassemblyLost;
+            this.wireDropped = wireDropped;
+            this.malformed = malformed;
+            this.sendDroppedVideoP = sendDroppedVideoP;
+            this.recvVideoDecodeErrors = recvVideoDecodeErrors;
+            this.recvDamagedVideoFrames = recvDamagedVideoFrames;
+        }
+
+        static UdpStats fromJson(JSONObject o) {
+            if (o == null) {
+                return new UdpStats(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+            }
+            return new UdpStats(
+                    o.optLong("datagrams_tx", 0L),
+                    o.optLong("datagrams_rx", 0L),
+                    o.optLong("datagrams_invalid", 0L),
+                    o.optLong("fragments_rx", 0L),
+                    o.optLong("fragments_duplicate", 0L),
+                    o.optLong("reassembly_ok", 0L),
+                    o.optLong("reassembly_lost", 0L),
+                    o.optLong("wire_dropped", 0L),
+                    o.optLong("malformed", 0L),
+                    o.optLong("send_dropped_video_p", 0L),
+                    o.optLong("recv_video_decode_errors", 0L),
+                    o.optLong("recv_damaged_video_frames", 0L));
+        }
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsAnalyzerActivity.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsAnalyzerActivity.java
new file mode 100644
index 0000000..d322019
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsAnalyzerActivity.java
@@ -0,0 +1,182 @@
+package com.foxx.androidcast.stats.ui;
+
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.RadioGroup;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.content.FileProvider;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.foxx.androidcast.AppPreferences;
+import com.foxx.androidcast.CastLocaleHelper;
+import com.foxx.androidcast.CastThemeHelper;
+import com.foxx.androidcast.R;
+import com.foxx.androidcast.stats.SessionStatsStore;
+import com.foxx.androidcast.util.CastBackgroundExecutor;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/** In-app viewer for saved session_send_* / session_recv_* cast statistics. */
+public class SessionStatsAnalyzerActivity extends AppCompatActivity
+        implements SessionStatsListAdapter.Listener {
+    private SessionLineChartView lineChart;
+    private SessionBarChartView barChart;
+    private TextView summaryText;
+    private TextView emptyText;
+    private View detailPanel;
+    private SessionRecord primarySelection;
+    private SessionLineChartView.Metric chartMetric = SessionLineChartView.Metric.BITRATE;
+    private List<SessionRecord> chartSessions = new ArrayList<>();
+
+    @Override
+    protected void attachBaseContext(android.content.Context newBase) {
+        super.attachBaseContext(CastLocaleHelper.attach(newBase));
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        CastThemeHelper.applyTheme(this);
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_session_stats_analyzer);
+        setTitle(R.string.session_stats_title);
+
+        if (getSupportActionBar() != null) {
+            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+        }
+
+        emptyText = findViewById(R.id.text_session_stats_empty);
+        detailPanel = findViewById(R.id.panel_session_detail);
+        summaryText = findViewById(R.id.text_session_summary);
+        lineChart = findViewById(R.id.chart_session_lines);
+        barChart = findViewById(R.id.chart_session_bars);
+        RecyclerView list = findViewById(R.id.list_sessions);
+
+        SessionStatsListAdapter adapter = new SessionStatsListAdapter(this);
+        list.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
+        list.setAdapter(adapter);
+
+        setupMetricRadios();
+        findViewById(R.id.btn_share_session).setOnClickListener(v -> shareSelected());
+        findViewById(R.id.btn_refresh_sessions).setOnClickListener(v -> reloadSessions(adapter));
+
+        TextView hint = findViewById(R.id.text_chart_interaction_hint);
+        if (hint != null) {
+            hint.setText(R.string.session_stats_chart_hint);
+        }
+
+        if (!AppPreferences.isGrabSessionStats(this)) {
+            Toast.makeText(this, R.string.session_stats_disabled_hint, Toast.LENGTH_LONG).show();
+        }
+        reloadSessions(adapter);
+    }
+
+    @Override
+    public boolean onSupportNavigateUp() {
+        finish();
+        return true;
+    }
+
+    private void setupMetricRadios() {
+        RadioGroup group = findViewById(R.id.radio_group_metric);
+        if (group == null) {
+            return;
+        }
+        group.setOnCheckedChangeListener((g, id) -> {
+            if (id == R.id.radio_metric_loss) {
+                chartMetric = SessionLineChartView.Metric.LOSS;
+            } else if (id == R.id.radio_metric_fps) {
+                chartMetric = SessionLineChartView.Metric.ENCODE_FPS;
+            } else {
+                chartMetric = SessionLineChartView.Metric.BITRATE;
+            }
+            refreshChart();
+        });
+    }
+
+    private void reloadSessions(SessionStatsListAdapter adapter) {
+        emptyText.setVisibility(View.VISIBLE);
+        detailPanel.setVisibility(View.GONE);
+        CastBackgroundExecutor.execute(() -> {
+            List<SessionRecord> loaded = new ArrayList<>();
+            List<File> files = SessionStatsStore.listSessionFiles(this);
+            for (File f : files) {
+                try {
+                    loaded.add(SessionStatsParser.load(f));
+                } catch (Exception ignored) {
+                }
+            }
+            runOnUiThread(() -> {
+                adapter.setItems(loaded);
+                boolean has = !loaded.isEmpty();
+                emptyText.setVisibility(has ? View.GONE : View.VISIBLE);
+                emptyText.setText(has ? "" : getString(R.string.session_stats_empty));
+                detailPanel.setVisibility(has ? View.VISIBLE : View.GONE);
+            });
+        });
+    }
+
+    @Override
+    public void onSelectionChanged(List<SessionRecord> selected) {
+        chartSessions = selected != null ? selected : new ArrayList<>();
+        primarySelection = chartSessions.isEmpty() ? null : chartSessions.get(0);
+        refreshChart();
+        if (primarySelection != null) {
+            summaryText.setText(buildSummary(primarySelection));
+            barChart.setSession(primarySelection);
+        }
+    }
+
+    private void refreshChart() {
+        lineChart.setSessions(chartSessions, chartMetric);
+    }
+
+    private String buildSummary(SessionRecord r) {
+        StringBuilder sb = new StringBuilder();
+        sb.append(r.role).append(" · ").append(r.transport).append('\n');
+        sb.append(String.format(Locale.US, "Duration: %d ms\n", r.durationMs));
+        if (!r.videoCodec.isEmpty()) {
+            sb.append("Video: ").append(r.videoCodec).append('\n');
+        }
+        if (!r.resolution.isEmpty()) {
+            sb.append("Resolution: ").append(r.resolution).append('\n');
+        }
+        sb.append(String.format(Locale.US, "Disrupts: %d  idle timeouts: %d\n",
+                r.disruptCount, r.idleTimeoutCount));
+        if (r.networkSamples > 0) {
+            sb.append(String.format(Locale.US, "Avg RTT: %d ms  loss: %.3f  bitrate: %d kbps  fps: %.1f\n",
+                    r.avgRttMs, r.avgLossRatio, r.avgVideoBitrateKbps, r.avgEncodeFps));
+        }
+        SessionRecord.ProtectionStats p = r.protection;
+        sb.append(String.format(Locale.US, "Protection: %s (FEC=%s NACK=%s)\n",
+                p.mode, p.fecEnabled, p.nackEnabled));
+        sb.append(String.format(Locale.US, "Samples in chart: %d", r.samples.size()));
+        return sb.toString().trim();
+    }
+
+    private void shareSelected() {
+        if (primarySelection == null) {
+            return;
+        }
+        File dir = SessionStatsStore.statsDir(this);
+        File file = new File(dir, primarySelection.fileName);
+        if (!file.isFile()) {
+            Toast.makeText(this, R.string.session_stats_share_failed, Toast.LENGTH_SHORT).show();
+            return;
+        }
+        Uri uri = FileProvider.getUriForFile(this, getPackageName() + ".fileprovider", file);
+        Intent send = new Intent(Intent.ACTION_SEND);
+        send.setType("application/json");
+        send.putExtra(Intent.EXTRA_STREAM, uri);
+        send.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+        startActivity(Intent.createChooser(send, getString(R.string.session_stats_share)));
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsListAdapter.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsListAdapter.java
new file mode 100644
index 0000000..89b9eef
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsListAdapter.java
@@ -0,0 +1,105 @@
+package com.foxx.androidcast.stats.ui;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.foxx.androidcast.R;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+final class SessionStatsListAdapter extends RecyclerView.Adapter<SessionStatsListAdapter.Holder> {
+    interface Listener {
+        void onSelectionChanged(List<SessionRecord> selected);
+    }
+
+    private final List<SessionRecord> items = new ArrayList<>();
+    private final Set<Integer> selectedPositions = new HashSet<>();
+    private final Listener listener;
+
+    SessionStatsListAdapter(Listener listener) {
+        this.listener = listener;
+    }
+
+    void setItems(List<SessionRecord> records) {
+        items.clear();
+        selectedPositions.clear();
+        if (records != null) {
+            items.addAll(records);
+            for (int i = 0; i < items.size(); i++) {
+                selectedPositions.add(i);
+            }
+        }
+        notifyDataSetChanged();
+        notifySelection();
+    }
+
+    List<SessionRecord> getSelected() {
+        List<SessionRecord> out = new ArrayList<>();
+        for (int i : selectedPositions) {
+            if (i >= 0 && i < items.size()) {
+                out.add(items.get(i));
+            }
+        }
+        return out;
+    }
+
+    @NonNull
+    @Override
+    public Holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View v = LayoutInflater.from(parent.getContext())
+                .inflate(R.layout.item_session_stats, parent, false);
+        return new Holder(v);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull Holder holder, int position) {
+        SessionRecord r = items.get(position);
+        holder.title.setText(r.fileName);
+        holder.subtitle.setText(r.listSubtitle());
+        boolean selected = selectedPositions.contains(position);
+        holder.itemView.setAlpha(selected ? 1f : 0.45f);
+        holder.itemView.setOnClickListener(v -> {
+            int pos = holder.getBindingAdapterPosition();
+            if (pos == RecyclerView.NO_POSITION) {
+                return;
+            }
+            if (selectedPositions.contains(pos)) {
+                selectedPositions.remove(pos);
+            } else {
+                selectedPositions.add(pos);
+            }
+            notifyItemChanged(pos);
+            notifySelection();
+        });
+    }
+
+    private void notifySelection() {
+        if (listener != null) {
+            listener.onSelectionChanged(getSelected());
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        return items.size();
+    }
+
+    static final class Holder extends RecyclerView.ViewHolder {
+        final TextView title;
+        final TextView subtitle;
+
+        Holder(@NonNull View itemView) {
+            super(itemView);
+            title = itemView.findViewById(R.id.text_session_title);
+            subtitle = itemView.findViewById(R.id.text_session_subtitle);
+        }
+    }
+}
diff --git a/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsParser.java b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsParser.java
new file mode 100644
index 0000000..6d1b9fe
--- /dev/null
+++ b/app/src/main/java/com/foxx/androidcast/stats/ui/SessionStatsParser.java
@@ -0,0 +1,22 @@
+package com.foxx.androidcast.stats.ui;
+
+import org.json.JSONObject;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+/** Loads {@link SessionRecord} from on-device session JSON files. */
+public final class SessionStatsParser {
+    private SessionStatsParser() {}
+
+    public static SessionRecord load(File file) throws Exception {
+        if (file == null || !file.isFile()) {
+            throw new IllegalArgumentException("Not a file");
+        }
+        byte[] bytes = Files.readAllBytes(file.toPath());
+        String text = new String(bytes, StandardCharsets.UTF_8);
+        JSONObject root = new JSONObject(text);
+        return new SessionRecord(file.getName(), root);
+    }
+}
diff --git a/app/src/main/res/layout/activity_developer_settings.xml b/app/src/main/res/layout/activity_developer_settings.xml
index fe4da1e..140a26e 100644
--- a/app/src/main/res/layout/activity_developer_settings.xml
+++ b/app/src/main/res/layout/activity_developer_settings.xml
@@ -39,10 +39,17 @@
             android:text="@string/dev_grab_session_stats" />
 
         <Button
-            android:id="@+id/btn_reload_codecs_json"
+            android:id="@+id/btn_open_session_stats"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="20dp"
+            android:text="@string/session_stats_open" />
+
+        <Button
+            android:id="@+id/btn_reload_codecs_json"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
             android:text="@string/dev_reload_codecs_json" />
 
         <TextView
diff --git a/app/src/main/res/layout/activity_session_stats_analyzer.xml b/app/src/main/res/layout/activity_session_stats_analyzer.xml
new file mode 100644
index 0000000..3ae8065
--- /dev/null
+++ b/app/src/main/res/layout/activity_session_stats_analyzer.xml
@@ -0,0 +1,128 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="12dp">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/session_stats_subtitle"
+        android:textSize="13sp" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="8dp"
+        android:orientation="horizontal">
+
+        <Button
+            android:id="@+id/btn_refresh_sessions"
+            style="@style/Widget.MaterialComponents.Button.TextButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/session_stats_refresh" />
+
+        <Button
+            android:id="@+id/btn_share_session"
+            style="@style/Widget.MaterialComponents.Button.TextButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/session_stats_share" />
+    </LinearLayout>
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/list_sessions"
+        android:layout_width="match_parent"
+        android:layout_height="120dp"
+        android:layout_marginTop="4dp"
+        android:clipToPadding="false"
+        android:paddingStart="4dp"
+        android:paddingEnd="4dp" />
+
+    <TextView
+        android:id="@+id/text_session_stats_empty"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="24dp"
+        android:gravity="center"
+        android:text="@string/session_stats_empty"
+        android:visibility="gone" />
+
+    <ScrollView
+        android:id="@+id/panel_session_detail"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_marginTop="8dp"
+        android:layout_weight="1"
+        android:fillViewport="true">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical">
+
+            <TextView
+                android:id="@+id/text_session_summary"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:fontFamily="monospace"
+                android:textSize="12sp" />
+
+            <RadioGroup
+                android:id="@+id/radio_group_metric"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:orientation="horizontal">
+
+                <RadioButton
+                    android:id="@+id/radio_metric_bitrate"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:checked="true"
+                    android:text="@string/session_stats_metric_bitrate" />
+
+                <RadioButton
+                    android:id="@+id/radio_metric_loss"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="@string/session_stats_metric_loss" />
+
+                <RadioButton
+                    android:id="@+id/radio_metric_fps"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="@string/session_stats_metric_fps" />
+            </RadioGroup>
+
+            <TextView
+                android:id="@+id/text_chart_interaction_hint"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4dp"
+                android:textSize="11sp" />
+
+            <com.foxx.androidcast.stats.ui.SessionLineChartView
+                android:id="@+id/chart_session_lines"
+                android:layout_width="match_parent"
+                android:layout_height="320dp"
+                android:layout_marginTop="4dp" />
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:text="@string/session_stats_counters_title"
+                android:textStyle="bold" />
+
+            <com.foxx.androidcast.stats.ui.SessionBarChartView
+                android:id="@+id/chart_session_bars"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4dp" />
+        </LinearLayout>
+    </ScrollView>
+</LinearLayout>
diff --git a/app/src/main/res/layout/item_session_stats.xml b/app/src/main/res/layout/item_session_stats.xml
new file mode 100644
index 0000000..4c11788
--- /dev/null
+++ b/app/src/main/res/layout/item_session_stats.xml
@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="220dp"
+    android:layout_height="match_parent"
+    android:layout_marginEnd="8dp"
+    android:checkable="true"
+    android:clickable="true"
+    android:focusable="true"
+    app:cardBackgroundColor="?attr/colorSurfaceVariant"
+    app:cardCornerRadius="8dp"
+    app:strokeWidth="2dp"
+    app:strokeColor="?attr/colorPrimary">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:padding="12dp">
+
+        <TextView
+            android:id="@+id/text_session_title"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textSize="13sp"
+            android:textStyle="bold" />
+
+        <TextView
+            android:id="@+id/text_session_subtitle"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="4dp"
+            android:textSize="11sp" />
+    </LinearLayout>
+</com.google.android.material.card.MaterialCardView>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 06f0482..94786bc 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -201,6 +201,19 @@
     <string name="dev_show_receiver_debug_overlay">Show debug overlay on receiver</string>
     <string name="dev_show_codec_priority_scores">Show codec priority scores in settings</string>
     <string name="dev_grab_session_stats">Grab anonymous session stats</string>
+    <string name="session_stats_title">Session statistics</string>
+    <string name="session_stats_subtitle">Charts from session_send_* / session_recv_* JSON (enable grab in developer settings, then cast).</string>
+    <string name="session_stats_open">Open statistics analyzer</string>
+    <string name="session_stats_refresh">Refresh</string>
+    <string name="session_stats_share">Share JSON</string>
+    <string name="session_stats_empty">No session files yet. Cast with “Grab session stats” enabled.</string>
+    <string name="session_stats_disabled_hint">Session grab is off — enable it here to record new sessions.</string>
+    <string name="session_stats_counters_title">UDP &amp; protection counters</string>
+    <string name="session_stats_share_failed">Could not share session file</string>
+    <string name="session_stats_metric_bitrate">Bitrate</string>
+    <string name="session_stats_metric_loss">Loss %</string>
+    <string name="session_stats_metric_fps">Encode FPS</string>
+    <string name="session_stats_chart_hint">Tap sessions to toggle overlay. Pinch or scroll wheel to zoom. Drag finger for values.</string>
     <string name="dev_reload_codecs_json">Reload codecs.json</string>
     <string name="dev_reload_codecs_json_hint">Loads assets/codecs.json overrides without restarting the app. Reopen the settings drawer to refresh spinners.</string>
     <string name="codec_priority_score_suffix"> · %1$d</string>
diff --git a/app/src/main/res/xml/file_paths.xml b/app/src/main/res/xml/file_paths.xml
new file mode 100644
index 0000000..d31665b
--- /dev/null
+++ b/app/src/main/res/xml/file_paths.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+    <files-path name="session_stats" path="session_stats/" />
+</paths>
diff --git a/app/src/test/java/com/foxx/androidcast/stats/SessionStatsEventMapperTest.java b/app/src/test/java/com/foxx/androidcast/stats/SessionStatsEventMapperTest.java
new file mode 100644
index 0000000..1039772
--- /dev/null
+++ b/app/src/test/java/com/foxx/androidcast/stats/SessionStatsEventMapperTest.java
@@ -0,0 +1,38 @@
+package com.foxx.androidcast.stats;
+
+import static org.junit.Assert.assertEquals;
+
+import com.foxx.androidcast.network.CastProtocol;
+
+import org.junit.Test;
+
+public class SessionStatsEventMapperTest {
+
+    @Test
+    public void videoKeyframe() {
+        assertEquals(SessionStatsEventMapper.KF,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_VIDEO_FRAME, true));
+        assertEquals(SessionStatsEventMapper.VIDEO,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_VIDEO_FRAME, false));
+    }
+
+    @Test
+    public void audioAndMeta() {
+        assertEquals(SessionStatsEventMapper.AUDIO,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_AUDIO_FRAME, false));
+        assertEquals(SessionStatsEventMapper.META,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_STREAM_CONFIG, false));
+        assertEquals(SessionStatsEventMapper.META,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_NETWORK_STATS, false));
+    }
+
+    @Test
+    public void serviceAndUnknown() {
+        assertEquals(SessionStatsEventMapper.SERVICE,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_HELLO, false));
+        assertEquals(SessionStatsEventMapper.SERVICE,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_CODEC_SELECTED, false));
+        assertEquals(SessionStatsEventMapper.UNKNOWN,
+                SessionStatsEventMapper.eventTypeForMessage(CastProtocol.MSG_NACK, false));
+    }
+}
diff --git a/app/src/test/java/com/foxx/androidcast/stats/SessionStatsStoreTest.java b/app/src/test/java/com/foxx/androidcast/stats/SessionStatsStoreTest.java
index fd79f1d..d5e3a40 100644
--- a/app/src/test/java/com/foxx/androidcast/stats/SessionStatsStoreTest.java
+++ b/app/src/test/java/com/foxx/androidcast/stats/SessionStatsStoreTest.java
@@ -39,4 +39,32 @@ public class SessionStatsStoreTest {
         }
         assertTrue(dir.delete());
     }
+
+    @Test
+    public void prefixForDirection() {
+        assertEquals(SessionStatsStore.PREFIX_SEND, SessionStatsStore.prefixForDirection("send"));
+        assertEquals(SessionStatsStore.PREFIX_RECV, SessionStatsStore.prefixForDirection("recv"));
+        assertEquals(SessionStatsStore.PREFIX_SEND, SessionStatsStore.prefixForDirection(null));
+    }
+
+    @Test
+    public void pruneDirectory_includesSendAndRecvPrefixes() throws IOException {
+        File dir = Files.createTempDirectory("session_stats_prefix").toFile();
+        new File(dir, "session_send_20260101_000001.json").createNewFile();
+        new File(dir, "session_recv_20260101_000002.json").createNewFile();
+        new File(dir, "session_20260101_000003.json").createNewFile();
+        new File(dir, "other.txt").createNewFile();
+
+        SessionStatsStore.pruneDirectory(dir, 2);
+
+        String[] remaining = dir.list((d, n) -> n.endsWith(".json"));
+        Arrays.sort(remaining);
+        assertEquals(1, remaining.length);
+        assertEquals("session_send_20260101_000001.json", remaining[0]);
+
+        for (File f : dir.listFiles()) {
+            assertTrue(f.delete());
+        }
+        assertTrue(dir.delete());
+    }
 }
diff --git a/desktop/README.md b/desktop/README.md
index a12099d..572a71a 100644
--- a/desktop/README.md
+++ b/desktop/README.md
@@ -8,7 +8,7 @@ JavaFX desktop app for **session log analysis** (Linux `.jar` or native image la
 ./gradlew :session-studio:run
 ```
 
-Open `session_*.json` from the device (`files/session_stats/`). New captures include a `samples[]` time series (~2 s) for charts.
+Open `session_send_*` / `session_recv_*` JSON from the device (`files/session_stats/`). Legacy `session_*.json` still loads. Charts use `samples[]` (~2 s): bitrate, loss %, encode FPS.
 
 ### Roadmap (full mobile parity + analytics)
 
diff --git a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/ChartTicks.java b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/ChartTicks.java
new file mode 100644
index 0000000..a8d3c76
--- /dev/null
+++ b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/ChartTicks.java
@@ -0,0 +1,79 @@
+package com.foxx.androidcast.studio;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/** Nice axis tick steps for charts. */
+final class ChartTicks {
+    private ChartTicks() {}
+
+    static final class Tick {
+        final double value;
+        final String label;
+
+        Tick(double value, String label) {
+            this.value = value;
+            this.label = label;
+        }
+    }
+
+    static List<Tick> linear(double min, double max, int maxTicks) {
+        List<Tick> out = new ArrayList<>();
+        if (!Double.isFinite(min) || !Double.isFinite(max) || max <= min) {
+            return out;
+        }
+        double step = niceStep(max - min, maxTicks);
+        double start = Math.ceil(min / step) * step;
+        for (double v = start; v <= max + step * 0.001; v += step) {
+            out.add(new Tick(v, formatValue(v, step)));
+        }
+        return out;
+    }
+
+    static List<Tick> timeMs(long minMs, long maxMs, int maxTicks) {
+        List<Tick> out = new ArrayList<>();
+        if (maxMs <= minMs) {
+            return out;
+        }
+        double range = maxMs - minMs;
+        double step = niceStep(range, maxTicks);
+        double start = Math.ceil(minMs / step) * step;
+        for (double v = start; v <= maxMs + step * 0.001; v += step) {
+            long ms = Math.round(v);
+            out.add(new Tick(ms, formatTimeMs(ms)));
+        }
+        return out;
+    }
+
+    private static double niceStep(double range, int maxTicks) {
+        double raw = range / Math.max(2, maxTicks);
+        if (raw <= 0) {
+            return 1;
+        }
+        double mag = Math.pow(10, Math.floor(Math.log10(raw)));
+        double norm = raw / mag;
+        double nice = norm <= 1 ? 1 : norm <= 2 ? 2 : norm <= 5 ? 5 : 10;
+        return nice * mag;
+    }
+
+    private static String formatValue(double v, double step) {
+        if (step >= 1) {
+            return String.format(Locale.US, "%.0f", v);
+        }
+        if (step >= 0.1) {
+            return String.format(Locale.US, "%.1f", v);
+        }
+        return String.format(Locale.US, "%.2f", v);
+    }
+
+    private static String formatTimeMs(long ms) {
+        if (ms >= 60_000) {
+            return String.format(Locale.US, "%.1fm", ms / 60_000.0);
+        }
+        if (ms >= 1000) {
+            return String.format(Locale.US, "%.1fs", ms / 1000.0);
+        }
+        return ms + "ms";
+    }
+}
diff --git a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionChartPane.java b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionChartPane.java
index 025ac60..a428be0 100644
--- a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionChartPane.java
+++ b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionChartPane.java
@@ -3,172 +3,354 @@ package com.foxx.androidcast.studio;
 import javafx.scene.canvas.Canvas;
 import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.input.MouseEvent;
+import javafx.scene.input.ScrollEvent;
 import javafx.scene.layout.StackPane;
 import javafx.scene.paint.Color;
 import javafx.scene.text.Font;
+import javafx.scene.text.FontWeight;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 
-/** Multi-series line chart with hover tooltip for session samples. */
+/** Multi-session line chart: zoom, grid, legend, hover marker + tooltip. */
 public final class SessionChartPane extends StackPane {
-    private static final Color[] SERIES_COLORS = {
-            Color.CORNFLOWERBLUE, Color.ORANGERED, Color.MEDIUMSEAGREEN, Color.GOLD, Color.VIOLET
+    public enum Metric {
+        BITRATE("Video bitrate (kbps)"),
+        LOSS("Packet loss (%)"),
+        ENCODE_FPS("Encode FPS");
+
+        final String axisLabel;
+
+        Metric(String axisLabel) {
+            this.axisLabel = axisLabel;
+        }
+    }
+
+    private static final Color[] SESSION_COLORS = {
+            Color.web("#64B5F6"), Color.web("#FF8A65"), Color.web("#81C784"),
+            Color.web("#FFD54F"), Color.web("#BA68C8"), Color.web("#4DD0E1")
     };
 
+    private static final double PAD_LEFT = 64;
+    private static final double PAD_RIGHT = 16;
+    private static final double PAD_TOP = 16;
+    private static final double PAD_BOTTOM = 40;
+    private static final Color GRID_COLOR = Color.web("#3a3a3a");
+    private static final Color AXIS_COLOR = Color.web("#aaaaaa");
+
     private final Canvas canvas = new Canvas(800, 480);
     private final List<SessionDocument> sessions = new ArrayList<>();
-    private boolean absoluteTime = true;
-    private boolean showBitrate = true;
-    private boolean showRtt;
-    private boolean showLoss;
-    private String hoverText = "";
+    private Metric metric = Metric.BITRATE;
+
+    private double viewMinT;
+    private double viewMaxT = 1;
+    private double viewMinY;
+    private double viewMaxY = 1;
+    private boolean viewInitialized;
+
+    private double hoverMouseX = -1;
+    private double hoverMouseY = -1;
+    private int hoverSessionIndex = -1;
+    private SessionDocument.SamplePoint hoverPoint;
+    private double hoverPlotX;
+    private double hoverPlotY;
 
     public SessionChartPane() {
         getChildren().add(canvas);
         canvas.widthProperty().bind(widthProperty());
-        canvas.heightProperty().bind(heightProperty().subtract(0));
+        canvas.heightProperty().bind(heightProperty());
         canvas.addEventHandler(MouseEvent.MOUSE_MOVED, this::onMouseMoved);
-        canvas.addEventHandler(MouseEvent.MOUSE_EXITED, e -> {
-            hoverText = "";
-            draw();
-        });
+        canvas.addEventHandler(MouseEvent.MOUSE_EXITED, e -> clearHover());
+        canvas.addEventHandler(ScrollEvent.SCROLL, this::onScroll);
     }
 
-    public void setAbsoluteTime(boolean absoluteTime) {
-        this.absoluteTime = absoluteTime;
-    }
-
-    public void render(List<SessionDocument> docs, boolean bitrate, boolean rtt, boolean loss) {
+    public void render(List<SessionDocument> docs, Metric metric) {
         sessions.clear();
         if (docs != null) {
             sessions.addAll(docs);
         }
-        showBitrate = bitrate;
-        showRtt = rtt;
-        showLoss = loss;
+        this.metric = metric != null ? metric : Metric.BITRATE;
+        resetView();
         draw();
     }
 
-    private void onMouseMoved(MouseEvent e) {
-        if (sessions.isEmpty()) {
-            return;
-        }
-        double pad = 48;
-        double w = canvas.getWidth() - pad * 2;
-        double h = canvas.getHeight() - pad * 2;
-        if (w <= 0 || h <= 0) {
-            return;
-        }
-        long tMax = maxTimeMs();
-        if (tMax <= 0) {
-            return;
-        }
-        double relX = (e.getX() - pad) / w;
-        if (relX < 0 || relX > 1) {
-            hoverText = "";
-            draw();
-            return;
-        }
-        long tQuery = (long) (relX * tMax);
-        SessionDocument doc = sessions.get(0);
-        SessionDocument.SamplePoint nearest = null;
-        long best = Long.MAX_VALUE;
-        for (SessionDocument.SamplePoint p : doc.samples) {
-            long d = Math.abs(p.tMs - tQuery);
-            if (d < best) {
-                best = d;
-                nearest = p;
-            }
-        }
-        if (nearest != null) {
-            hoverText = String.format("t=%d ms  bitrate=%.0f kbps  rtt=%d ms  loss=%.3f",
-                    nearest.tMs, nearest.videoBitrateKbps, nearest.rttMs, nearest.lossRatio);
-        }
-        draw();
+    private void resetView() {
+        viewMinT = 0;
+        viewMaxT = Math.max(1, dataMaxTimeMs());
+        double[] y = dataYRange();
+        viewMinY = y[0];
+        viewMaxY = y[1];
+        viewInitialized = sessions.stream().anyMatch(d -> d.samples.size() >= 2);
     }
 
-    private long maxTimeMs() {
+    private long dataMaxTimeMs() {
         long max = 1;
         for (SessionDocument doc : sessions) {
             for (SessionDocument.SamplePoint p : doc.samples) {
                 max = Math.max(max, p.tMs);
             }
-            if (!absoluteTime && doc.durationMs > max) {
-                max = doc.durationMs;
-            }
+            max = Math.max(max, doc.durationMs);
         }
         return max;
     }
 
+    private double[] dataYRange() {
+        double min = Double.POSITIVE_INFINITY;
+        double max = Double.NEGATIVE_INFINITY;
+        for (SessionDocument doc : sessions) {
+            for (SessionDocument.SamplePoint p : doc.samples) {
+                double v = metricValue(p);
+                if (Double.isFinite(v)) {
+                    min = Math.min(min, v);
+                    max = Math.max(max, v);
+                }
+            }
+        }
+        if (!Double.isFinite(min)) {
+            min = 0;
+            max = 1;
+        }
+        if (max <= min) {
+            max = min + 1;
+        }
+        double pad = (max - min) * 0.06;
+        return new double[] {min - pad, max + pad};
+    }
+
+    private void onScroll(ScrollEvent e) {
+        if (!viewInitialized) {
+            return;
+        }
+        double plotW = plotWidth();
+        double plotH = plotHeight();
+        if (plotW <= 0 || plotH <= 0) {
+            return;
+        }
+        double factor = e.getDeltaY() > 0 ? 0.85 : 1.0 / 0.85;
+        double mx = e.getX();
+        double my = e.getY();
+        if (mx >= PAD_LEFT && mx <= PAD_LEFT + plotW && my >= PAD_TOP && my <= PAD_TOP + plotH) {
+            double relX = (mx - PAD_LEFT) / plotW;
+            double relY = 1.0 - (my - PAD_TOP) / plotH;
+            double tAnchor = viewMinT + relX * (viewMaxT - viewMinT);
+            double yAnchor = viewMinY + relY * (viewMaxY - viewMinY);
+            zoomTime(tAnchor, factor);
+            zoomY(yAnchor, factor);
+        } else {
+            zoomTime((viewMinT + viewMaxT) / 2, factor);
+            zoomY((viewMinY + viewMaxY) / 2, factor);
+        }
+        e.consume();
+        draw();
+    }
+
+    private void zoomTime(double anchor, double factor) {
+        double span = viewMaxT - viewMinT;
+        if (span <= 0) {
+            return;
+        }
+        double newSpan = Math.max(50, span * factor);
+        viewMinT = anchor - (anchor - viewMinT) * (newSpan / span);
+        viewMaxT = viewMinT + newSpan;
+    }
+
+    private void zoomY(double anchor, double factor) {
+        double span = viewMaxY - viewMinY;
+        if (span <= 0) {
+            return;
+        }
+        double newSpan = Math.max(1, span * factor);
+        viewMinY = anchor - (anchor - viewMinY) * (newSpan / span);
+        viewMaxY = viewMinY + newSpan;
+    }
+
+    private void onMouseMoved(MouseEvent e) {
+        hoverMouseX = e.getX();
+        hoverMouseY = e.getY();
+        updateHoverHit();
+        draw();
+    }
+
+    private void clearHover() {
+        hoverMouseX = -1;
+        hoverMouseY = -1;
+        hoverSessionIndex = -1;
+        hoverPoint = null;
+        draw();
+    }
+
+    private void updateHoverHit() {
+        hoverSessionIndex = -1;
+        hoverPoint = null;
+        double plotW = plotWidth();
+        double plotH = plotHeight();
+        if (plotW <= 0 || plotH <= 0 || sessions.isEmpty()) {
+            return;
+        }
+        if (hoverMouseX < PAD_LEFT || hoverMouseX > PAD_LEFT + plotW
+                || hoverMouseY < PAD_TOP || hoverMouseY > PAD_TOP + plotH) {
+            return;
+        }
+        double bestDist = 24;
+        for (int si = 0; si < sessions.size(); si++) {
+            SessionDocument doc = sessions.get(si);
+            for (SessionDocument.SamplePoint p : doc.samples) {
+                if (p.tMs < viewMinT || p.tMs > viewMaxT) {
+                    continue;
+                }
+                double v = metricValue(p);
+                if (v < viewMinY || v > viewMaxY) {
+                    continue;
+                }
+                double x = toScreenX(p.tMs);
+                double y = toScreenY(v);
+                double d = Math.hypot(hoverMouseX - x, hoverMouseY - y);
+                if (d < bestDist) {
+                    bestDist = d;
+                    hoverSessionIndex = si;
+                    hoverPoint = p;
+                    hoverPlotX = x;
+                    hoverPlotY = y;
+                }
+            }
+        }
+    }
+
+    private double plotWidth() {
+        return Math.max(0, canvas.getWidth() - PAD_LEFT - PAD_RIGHT);
+    }
+
+    private double plotHeight() {
+        return Math.max(0, canvas.getHeight() - PAD_TOP - PAD_BOTTOM);
+    }
+
+    private double toScreenX(double tMs) {
+        double plotW = plotWidth();
+        double span = viewMaxT - viewMinT;
+        if (span <= 0) {
+            return PAD_LEFT;
+        }
+        return PAD_LEFT + ((tMs - viewMinT) / span) * plotW;
+    }
+
+    private double toScreenY(double v) {
+        double plotH = plotHeight();
+        double span = viewMaxY - viewMinY;
+        if (span <= 0) {
+            return PAD_TOP + plotH;
+        }
+        return PAD_TOP + plotH - ((v - viewMinY) / span) * plotH;
+    }
+
+    private double metricValue(SessionDocument.SamplePoint p) {
+        switch (metric) {
+            case LOSS:
+                return p.lossRatio * 100.0;
+            case ENCODE_FPS:
+                return p.encodeFps;
+            case BITRATE:
+            default:
+                return p.videoBitrateKbps;
+        }
+    }
+
     private void draw() {
         GraphicsContext g = canvas.getGraphicsContext2D();
         double w = canvas.getWidth();
         double h = canvas.getHeight();
-        g.setFill(Color.web("#1a1a1a"));
+        g.setFill(Color.web("#121212"));
         g.fillRect(0, 0, w, h);
+
         if (sessions.isEmpty()) {
             g.setFill(Color.LIGHTGRAY);
             g.setFont(Font.font(14));
-            g.fillText("Open session_*.json (enable Grab session stats on device)", 24, 40);
+            g.fillText("Open session_send_* / session_recv_* JSON (Grab session stats on device)", 24, 40);
             return;
         }
-        double pad = 48;
-        double plotW = w - pad * 2;
-        double plotH = h - pad * 2;
-        long tMax = maxTimeMs();
-        g.setStroke(Color.GRAY);
-        g.strokeRect(pad, pad, plotW, plotH);
 
-        int series = 0;
+        double plotW = plotWidth();
+        double plotH = plotHeight();
+        if (plotW <= 1 || plotH <= 1) {
+            return;
+        }
+
+        List<ChartTicks.Tick> xTicks = ChartTicks.timeMs(
+                (long) viewMinT, (long) viewMaxT, 8);
+        List<ChartTicks.Tick> yTicks = ChartTicks.linear(viewMinY, viewMaxY, 6);
+
+        g.setStroke(GRID_COLOR);
+        g.setLineWidth(1);
+        for (ChartTicks.Tick t : xTicks) {
+            double x = toScreenX(t.value);
+            g.strokeLine(x, PAD_TOP, x, PAD_TOP + plotH);
+        }
+        for (ChartTicks.Tick t : yTicks) {
+            double y = toScreenY(t.value);
+            g.strokeLine(PAD_LEFT, y, PAD_LEFT + plotW, y);
+        }
+
+        g.setStroke(AXIS_COLOR);
+        g.setLineWidth(1.5);
+        g.strokeLine(PAD_LEFT, PAD_TOP + plotH, PAD_LEFT + plotW, PAD_TOP + plotH);
+        g.strokeLine(PAD_LEFT, PAD_TOP, PAD_LEFT, PAD_TOP + plotH);
+
+        g.setFill(AXIS_COLOR);
+        g.setFont(Font.font(10));
+        for (ChartTicks.Tick t : xTicks) {
+            double x = toScreenX(t.value);
+            g.fillText(t.label, x - 16, PAD_TOP + plotH + 14);
+        }
+        for (ChartTicks.Tick t : yTicks) {
+            double y = toScreenY(t.value);
+            g.fillText(t.label, 4, y + 4);
+        }
+
+        g.setFill(Color.web("#cccccc"));
+        g.setFont(Font.font(11));
+        g.fillText("Time", PAD_LEFT + plotW / 2 - 16, h - 4);
+        g.save();
+        g.translate(12, PAD_TOP + plotH / 2);
+        g.rotate(-90);
+        g.fillText(metric.axisLabel, 0, 0);
+        g.restore();
+
         for (int si = 0; si < sessions.size(); si++) {
             SessionDocument doc = sessions.get(si);
-            if (doc.samples.isEmpty()) {
+            if (doc.samples.size() < 2) {
                 continue;
             }
-            Color color = SERIES_COLORS[si % SERIES_COLORS.length];
-            if (showBitrate) {
-                drawSeries(g, doc, pad, plotW, plotH, tMax, color,
-                        p -> p.videoBitrateKbps, 0, 20_000);
-                series++;
-            }
-            if (showRtt) {
-                drawSeries(g, doc, pad, plotW, plotH, tMax, color.deriveColor(0, 1, 1, 0.6),
-                        p -> p.rttMs, 0, 500);
-            }
-            if (showLoss) {
-                drawSeries(g, doc, pad, plotW, plotH, tMax, color.deriveColor(30, 1, 1, 0.6),
-                        p -> p.lossRatio * 1000, 0, 1000);
-            }
+            drawSessionLine(g, doc, SESSION_COLORS[si % SESSION_COLORS.length]);
         }
-        if (!hoverText.isEmpty()) {
-            g.setFill(Color.rgb(0, 0, 0, 0.75));
-            g.fillRoundRect(56, 12, Math.min(plotW, 420), 28, 8, 8);
-            g.setFill(Color.WHITE);
-            g.setFont(Font.font(12));
-            g.fillText(hoverText, 64, 30);
+
+        drawLegend(g, plotW);
+
+        if (hoverPoint != null && hoverSessionIndex >= 0) {
+            Color c = SESSION_COLORS[hoverSessionIndex % SESSION_COLORS.length];
+            g.setFill(c);
+            g.fillOval(hoverPlotX - 5, hoverPlotY - 5, 10, 10);
+            g.setStroke(Color.WHITE);
+            g.setLineWidth(1.5);
+            g.strokeOval(hoverPlotX - 5, hoverPlotY - 5, 10, 10);
+            drawHoverPopup(g, c);
         }
-        g.setFill(Color.LIGHTGRAY);
-        g.setFont(Font.font(11));
-        g.fillText(absoluteTime ? "X: ms from session start" : "X: relative (multi-session)", pad, h - 12);
     }
 
-    private interface ValueFn {
-        double value(SessionDocument.SamplePoint p);
-    }
-
-    private void drawSeries(GraphicsContext g, SessionDocument doc, double pad, double plotW, double plotH,
-            long tMax, Color color, ValueFn fn, double minY, double maxY) {
-        if (doc.samples.size() < 2) {
-            return;
-        }
+    private void drawSessionLine(GraphicsContext g, SessionDocument doc, Color color) {
         g.setStroke(color);
+        g.setLineWidth(2);
         g.beginPath();
         boolean first = true;
         for (SessionDocument.SamplePoint p : doc.samples) {
-            double x = pad + (p.tMs / (double) tMax) * plotW;
-            double v = fn.value(p);
-            double y = pad + plotH - ((v - minY) / (maxY - minY)) * plotH;
+            if (p.tMs < viewMinT || p.tMs > viewMaxT) {
+                continue;
+            }
+            double v = metricValue(p);
+            if (v < viewMinY || v > viewMaxY) {
+                continue;
+            }
+            double x = toScreenX(p.tMs);
+            double y = toScreenY(v);
             if (first) {
                 g.moveTo(x, y);
                 first = false;
@@ -178,4 +360,78 @@ public final class SessionChartPane extends StackPane {
         }
         g.stroke();
     }
+
+    private void drawLegend(GraphicsContext g, double plotW) {
+        double x0 = PAD_LEFT + plotW - 8;
+        double y = PAD_TOP + 8;
+        double rowH = 18;
+        double boxW = 14;
+        int rows = 0;
+        for (SessionDocument doc : sessions) {
+            if (!doc.samples.isEmpty()) {
+                rows++;
+            }
+        }
+        if (rows == 0) {
+            return;
+        }
+        double legendW = 220;
+        double legendH = rows * rowH + 12;
+        x0 -= legendW;
+        g.setFill(Color.rgb(0, 0, 0, 0.72));
+        g.fillRoundRect(x0, y, legendW, legendH, 6, 6);
+        g.setStroke(Color.web("#888888"));
+        g.strokeRoundRect(x0, y, legendW, legendH, 6, 6);
+
+        int row = 0;
+        for (int si = 0; si < sessions.size(); si++) {
+            SessionDocument doc = sessions.get(si);
+            if (doc.samples.isEmpty()) {
+                continue;
+            }
+            Color c = SESSION_COLORS[si % SESSION_COLORS.length];
+            double ry = y + 8 + row * rowH;
+            g.setFill(c);
+            g.fillRoundRect(x0 + 8, ry, boxW, boxW - 2, 2, 2);
+            g.setStroke(Color.web("#bbbbbb"));
+            g.strokeRoundRect(x0 + 8, ry, boxW, boxW - 2, 2, 2);
+            boolean bold = si == hoverSessionIndex;
+            g.setFill(Color.WHITE);
+            g.setFont(Font.font("System", bold ? FontWeight.BOLD : FontWeight.NORMAL, 11));
+            String name = doc.path;
+            if (name.length() > 26) {
+                name = "…" + name.substring(name.length() - 25);
+            }
+            g.fillText(name, x0 + 8 + boxW + 6, ry + 11);
+            row++;
+        }
+    }
+
+    private void drawHoverPopup(GraphicsContext g, Color accent) {
+        SessionDocument doc = sessions.get(hoverSessionIndex);
+        String text = String.format(Locale.US,
+                "t=%d ms  bitrate=%.0f kbps  loss=%.2f%%  fps=%.1f",
+                hoverPoint.tMs,
+                hoverPoint.videoBitrateKbps,
+                hoverPoint.lossRatio * 100.0,
+                hoverPoint.encodeFps);
+        double tw = Math.min(plotWidth() - 20, g.getFont().getSize() * 0.55 * text.length() + 20);
+        double th = 28;
+        double px = hoverPlotX + 12;
+        double py = hoverPlotY - th - 12;
+        if (px + tw > PAD_LEFT + plotWidth()) {
+            px = hoverPlotX - tw - 12;
+        }
+        if (py < PAD_TOP) {
+            py = hoverPlotY + 12;
+        }
+        g.setFill(Color.rgb(0, 0, 0, 0.88));
+        g.fillRoundRect(px, py, tw, th, 6, 6);
+        g.setStroke(accent);
+        g.setLineWidth(1);
+        g.strokeRoundRect(px, py, tw, th, 6, 6);
+        g.setFill(Color.WHITE);
+        g.setFont(Font.font(11));
+        g.fillText(text, px + 8, py + 18);
+    }
 }
diff --git a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionDocument.java b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionDocument.java
index ab8f358..5acbdd2 100644
--- a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionDocument.java
+++ b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionDocument.java
@@ -9,9 +9,10 @@ import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 
-/** Parsed session_*.json (aggregate fields + optional time series). */
+/** Parsed session JSON (aggregate fields + optional time series). */
 public final class SessionDocument {
     public final String path;
+    public final String direction;
     public final String role;
     public final String transport;
     public final long startedMs;
@@ -20,7 +21,8 @@ public final class SessionDocument {
 
     private SessionDocument(String path, JSONObject root) {
         this.path = path;
-        role = root.optString("role", "?");
+        direction = inferDirection(path, root);
+        role = root.optString("role", "recv".equals(direction) ? "receiver" : "sender");
         transport = root.optString("transport", "?");
         startedMs = root.optLong("started_at_epoch_ms", 0L);
         durationMs = root.optLong("duration_ms", 0L);
@@ -42,7 +44,23 @@ public final class SessionDocument {
     }
 
     public String title() {
-        return path + " (" + role + ", " + transport + ")";
+        return path + " (" + direction + ", " + transport + ")";
+    }
+
+    private static String inferDirection(String fileName, JSONObject root) {
+        String d = root.optString("direction", "");
+        if ("send".equals(d) || "recv".equals(d)) {
+            return d;
+        }
+        if (fileName != null) {
+            if (fileName.startsWith("session_send_")) {
+                return "send";
+            }
+            if (fileName.startsWith("session_recv_")) {
+                return "recv";
+            }
+        }
+        return "receiver".equals(root.optString("role", "")) ? "recv" : "send";
     }
 
     public static final class SamplePoint {
@@ -50,12 +68,17 @@ public final class SessionDocument {
         public final double videoBitrateKbps;
         public final int rttMs;
         public final double lossRatio;
+        public final double encodeFps;
+        public final int congestionLevel;
 
-        SamplePoint(long tMs, double videoBitrateKbps, int rttMs, double lossRatio) {
+        SamplePoint(long tMs, double videoBitrateKbps, int rttMs, double lossRatio,
+                double encodeFps, int congestionLevel) {
             this.tMs = tMs;
             this.videoBitrateKbps = videoBitrateKbps;
             this.rttMs = rttMs;
             this.lossRatio = lossRatio;
+            this.encodeFps = encodeFps;
+            this.congestionLevel = congestionLevel;
         }
 
         static SamplePoint fromJson(JSONObject o) {
@@ -63,7 +86,9 @@ public final class SessionDocument {
                     o.optLong("t_ms", 0L),
                     o.optDouble("video_bitrate_kbps", 0.0),
                     o.optInt("rtt_ms", 0),
-                    o.optDouble("loss_ratio", 0.0));
+                    o.optDouble("loss_ratio", 0.0),
+                    o.optDouble("encode_fps", 0.0),
+                    o.optInt("congestion_level", 0));
         }
     }
 }
diff --git a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionStudioApp.java b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionStudioApp.java
index a1183ed..248f322 100644
--- a/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionStudioApp.java
+++ b/desktop/session-studio/src/main/java/com/foxx/androidcast/studio/SessionStudioApp.java
@@ -1,12 +1,13 @@
 package com.foxx.androidcast.studio;
 
 import javafx.application.Application;
+import javafx.collections.ListChangeListener;
 import javafx.scene.Scene;
 import javafx.scene.control.Button;
 import javafx.scene.control.CheckBox;
 import javafx.scene.control.Label;
 import javafx.scene.control.ListView;
-import javafx.scene.control.ToggleGroup;
+import javafx.scene.control.SelectionMode;
 import javafx.scene.layout.BorderPane;
 import javafx.scene.layout.HBox;
 import javafx.scene.layout.VBox;
@@ -19,45 +20,71 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
- * Linux desktop session log viewer (foundation for full Android Cast parity on desktop).
- * Open one or more session_*.json files; charts use {@code samples[]} when present (schema v1+).
+ * Desktop session log viewer — open session_send_* / session_recv_* JSON, overlay charts.
  */
 public class SessionStudioApp extends Application {
 
     private final List<SessionDocument> sessions = new ArrayList<>();
     private final SessionChartPane chartPane = new SessionChartPane();
-    private final Label statusLabel = new Label("Open session_*.json files from the device.");
+    private final Label statusLabel = new Label("Open session_send_* / session_recv_* JSON from the device.");
 
     @Override
     public void start(Stage stage) {
         Button openBtn = new Button("Open sessions…");
 
-        CheckBox absTime = new CheckBox("Absolute time (single session)");
-        absTime.setSelected(true);
-        absTime.setOnAction(e -> chartPane.setAbsoluteTime(absTime.isSelected()));
-
-        ToggleGroup metrics = new ToggleGroup();
-        CheckBox metricBitrate = metricToggle(metrics, "Video bitrate", true);
-        CheckBox metricRtt = metricToggle(metrics, "RTT", false);
-        CheckBox metricLoss = metricToggle(metrics, "Loss ratio", false);
-        Runnable refresh = () -> chartPane.render(sessions,
-                metricBitrate.isSelected(), metricRtt.isSelected(), metricLoss.isSelected());
-        metricBitrate.setOnAction(e -> refresh.run());
-        metricRtt.setOnAction(e -> refresh.run());
-        metricLoss.setOnAction(e -> refresh.run());
-        absTime.setOnAction(e -> {
-            chartPane.setAbsoluteTime(absTime.isSelected());
-            refresh.run();
-        });
+        CheckBox metricBitrate = new CheckBox("Video bitrate");
+        metricBitrate.setSelected(true);
+        CheckBox metricLoss = new CheckBox("Packet loss %");
+        CheckBox metricFps = new CheckBox("Encode FPS");
 
         ListView<String> sessionList = new ListView<>();
-        sessionList.setPrefHeight(120);
-        sessionList.getSelectionModel().selectedIndexProperty().addListener((o, a, b) -> refresh.run());
+        sessionList.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
+        sessionList.setPrefHeight(100);
 
-        HBox toolbar = new HBox(12, openBtn, absTime, metricBitrate, metricRtt, metricLoss);
+        Runnable refresh = () -> {
+            List<SessionDocument> selected = selectedSessions(sessionList);
+            SessionChartPane.Metric metric = SessionChartPane.Metric.BITRATE;
+            if (metricLoss.isSelected()) {
+                metric = SessionChartPane.Metric.LOSS;
+            } else if (metricFps.isSelected()) {
+                metric = SessionChartPane.Metric.ENCODE_FPS;
+            } else if (metricBitrate.isSelected()) {
+                metric = SessionChartPane.Metric.BITRATE;
+            }
+            chartPane.render(selected, metric);
+        };
+
+        metricBitrate.setOnAction(e -> {
+            if (metricBitrate.isSelected()) {
+                metricLoss.setSelected(false);
+                metricFps.setSelected(false);
+            }
+            refresh.run();
+        });
+        metricLoss.setOnAction(e -> {
+            if (metricLoss.isSelected()) {
+                metricBitrate.setSelected(false);
+                metricFps.setSelected(false);
+            }
+            refresh.run();
+        });
+        metricFps.setOnAction(e -> {
+            if (metricFps.isSelected()) {
+                metricBitrate.setSelected(false);
+                metricLoss.setSelected(false);
+            }
+            refresh.run();
+        });
+        sessionList.getSelectionModel().getSelectedIndices()
+                .addListener((ListChangeListener<Integer>) c -> refresh.run());
+
+        HBox toolbar = new HBox(12, openBtn, metricBitrate, metricLoss, metricFps);
         toolbar.setStyle("-fx-padding: 8;");
 
-        VBox top = new VBox(8, toolbar, sessionList, statusLabel);
+        Label hint = new Label("Scroll wheel over chart to zoom X+Y. Hover a line for values. RTT removed — use loss % or bitrate.");
+        hint.setStyle("-fx-text-fill: #888; -fx-font-size: 11;");
+
+        VBox top = new VBox(8, toolbar, hint, sessionList, statusLabel);
         top.setStyle("-fx-padding: 8;");
 
         BorderPane root = new BorderPane();
@@ -67,7 +94,10 @@ public class SessionStudioApp extends Application {
             openFiles(stage);
             sessionList.getItems().clear();
             for (SessionDocument doc : sessions) {
-                sessionList.getItems().add(doc.title());
+                sessionList.getItems().add(doc.path);
+            }
+            if (!sessions.isEmpty()) {
+                sessionList.getSelectionModel().selectAll();
             }
             refresh.run();
         });
@@ -77,10 +107,17 @@ public class SessionStudioApp extends Application {
         stage.show();
     }
 
-    private static CheckBox metricToggle(ToggleGroup group, String text, boolean selected) {
-        CheckBox box = new CheckBox(text);
-        box.setSelected(selected);
-        return box;
+    private List<SessionDocument> selectedSessions(ListView<String> list) {
+        List<SessionDocument> out = new ArrayList<>();
+        for (int idx : list.getSelectionModel().getSelectedIndices()) {
+            if (idx >= 0 && idx < sessions.size()) {
+                out.add(sessions.get(idx));
+            }
+        }
+        if (out.isEmpty() && !sessions.isEmpty()) {
+            out.addAll(sessions);
+        }
+        return out;
     }
 
     private void openFiles(Stage stage) {
@@ -101,7 +138,7 @@ public class SessionStudioApp extends Application {
                 return;
             }
         }
-        statusLabel.setText("Loaded " + sessions.size() + " session file(s).");
+        statusLabel.setText("Loaded " + sessions.size() + " session file(s). Select rows to overlay.");
     }
 
     public static void main(String[] args) {
diff --git a/pull_stats.sh b/pull_stats.sh
index 1ee3264..5fe894f 100755
--- a/pull_stats.sh
+++ b/pull_stats.sh
@@ -9,6 +9,25 @@ filter_out() {
   return 0
 }
 
+LOG_ROOT="log_capture/session_stats/"
+CLEAN_LOGS="no"
+
+while true; do
+  read -p "clean logs on device after fetch? [Y/n]" yn
+  case $yn in
+    [Y|Yes|y|yes]* )
+      CLEAN_LOGS="yes"
+      break
+    ;;
+    [N|No|n|no]* )
+      break
+    ;;
+    *)
+      echo "answer Y(es) or N(no) (short y/n or yes/no)"
+    ;;
+  esac
+done
+
 echo "${DEVICES_LIST}" | while IFS= read -r DEV; do
   SERIAL="$(echo "${DEV}" | awk '{print $1}')"
   filter_out SERIAL
@@ -16,6 +35,14 @@ echo "${DEVICES_LIST}" | while IFS= read -r DEV; do
 #  echo "Device: ${DEV}"
 #  echo "Serial: ${SERIAL}"
   adb -s "${SERIAL}" shell run-as com.foxx.androidcast ls files/session_stats/
-  adb -s "${SERIAL}" shell run-as com.foxx.androidcast cat files/session_stats/session_*.json
+  LOG_PATH="${LOG_ROOT}/${SERIAL}/"
+  echo "------------ dumping in ${LOG_PATH}"
+  mkdir -p "${LOG_PATH}"
+  for f in $(adb -s ${SERIAL} shell run-as com.foxx.androidcast ls files/session_stats/); do
+    adb -s ${SERIAL} exec-out run-as com.foxx.androidcast cat "files/session_stats/$f" > "${LOG_PATH}/$f"
+    [[ "no" != "${CLEAN_LOGS}" ]] && adb -s ${SERIAL} shell run-as com.foxx.androidcast rm -f "files/session_stats/$f"
+  done
 done
 
+echo "run './gradlew :session-studio:run' to analyze logs; find the latest logs in ${LOG_ROOT}"
+
diff --git a/rebuild.sh b/rebuild.sh
index b6db45d..c142dce 100755
--- a/rebuild.sh
+++ b/rebuild.sh
@@ -5,16 +5,37 @@ set -euo pipefail
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "$ROOT"
 
-# Space-separated host:port list (wireless debugging). Edit as needed.
-CONNECTIONS_LIST=""
+# Hints for wireless debugging. Edit as needed.
+## CONNECTIONS_LIST_HINTS[IP_WITH_UNDERLINES]="hint string"
+declare -A CONNECTIONS_LIST_HINTS
 ## android tv projector / android 13
-CONNECTIONS_LIST="${CONNECTIONS_LIST} 192.168.33.153:5555"
+CONNECTIONS_LIST_HINTS["192_168_33_153"]="[A13] Android Projector"
 ## tab g6 max / android 16
-CONNECTIONS_LIST="${CONNECTIONS_LIST} 192.168.33.39:5555"
+CONNECTIONS_LIST_HINTS["192_168_33_39"]="[A16] Doogee Tab G6 Max / P8_EEA"
 ## bl6000pro main / android 11
-CONNECTIONS_LIST="${CONNECTIONS_LIST} 192.168.33.106:5555"
+CONNECTIONS_LIST_HINTS["192_168_33_106"]="[A11] BlackView BL6000Pro / BL6000Pro_EEA"
 ## bl6000pro aux / android 11
-CONNECTIONS_LIST="${CONNECTIONS_LIST} 192.168.33.173:5555"
+CONNECTIONS_LIST_HINTS["192_168_33_173"]="[A11] BlackView BL6000Pro / BL6000Pro"
+
+get_ip_for_hint_key() {
+  local ip=${1}
+  ip="$(echo "${ip}" | sed -e s'@_@\.@g' -e s'@:.*@@' | tr -d '\n' )"
+  printf "%s" "${ip}"
+}
+
+get_hint_key_for_ip() {
+  local ip=${1}
+  ip="$(echo "${ip}" | sed -e s'@\.@_@g' -e s'@:.*@@' | tr -d '\n' )"
+  printf "%s" "${ip}"
+}
+
+get_hint() {
+  local ip_mask="${1}"
+  local -n hint
+  ip_mask="$(get_hint_key_for_ip "${ip_mask}")"
+  hint=CONNECTIONS_LIST_HINTS[${ip_mask}]
+  printf "%s" "${hint}"
+}
 
 APK="$ROOT/app/build/outputs/apk/debug/app-debug.apk"
 PACKAGE="com.foxx.androidcast"
@@ -33,7 +54,7 @@ for arg in "$@"; do
       ;;
     -h|--help)
       echo "Usage: $0 [--skip-tests] [--java-home=PATH]"
-      echo "  Builds debug APK, runs unit tests (unless skipped), reconnects devices in CONNECTIONS_LIST,"
+      echo "  Builds debug APK, runs unit tests (unless skipped), reconnects devices in CONNECTIONS_LIST_HINTS,"
       echo "  installs on all adb devices in 'device' state, and launches the app."
       exit 0
       ;;
@@ -79,6 +100,10 @@ reconnect_endpoint() {
   local endpoint="$1"
   [[ -z "$endpoint" ]] && return 1
   local attempt out
+  local hint=""
+  hint="$(get_hint "${endpoint}")"
+  [[ -n "${hint}" ]] && hint="(having hint: ${hint})"
+  echo "   trying to connect to $endpoint ${hint}"
   adb disconnect "$endpoint" >/dev/null 2>&1 || true
   for (( attempt = 1; attempt <= ADB_CONNECT_RETRIES; attempt++ )); do
     out="$(adb connect "$endpoint" 2>&1)" || true
@@ -101,8 +126,8 @@ reconnect_known_devices() {
   adb start-server >/dev/null 2>&1 || true
   adb reconnect offline >/dev/null 2>&1 || true
   local endpoint
-  for endpoint in $CONNECTIONS_LIST; do
-    reconnect_endpoint "$endpoint" || true
+  for endpoint in "${!CONNECTIONS_LIST_HINTS[@]}"; do
+    reconnect_endpoint "$(get_ip_for_hint_key "$endpoint")" || true
   done
   adb devices -l
 }
@@ -133,7 +158,8 @@ done
 
 echo "==> Building debug APK (JAVA_HOME=$JAVA_HOME)"
 ./gradlew --stop
-./gradlew clean assembleDebug
+./gradlew clean
+./gradlew --build-cache assembleDebug
 
 if [[ "$RUN_UNIT_TESTS" == "1" ]]; then
   echo "==> Running unit tests (./gradlew testDebugUnitTest)"