codecs: real Opus + Speex JNI encode/decode; SFU gate enabled

- opus_bridge.c / speex_bridge.c: full encoder + decoder JNI (libopus/libspeex)
- NativeCodecBridge: add Opus/Speex encode/decode/release public Java API
- OpusAudioEncoderSink / SpeexAudioEncoderSink: real AudioEncoderSink impls
- AudioCodecFactory: route OPUS_NATIVE → OpusAudioEncoderSink, SPEEX_NATIVE → SpeexAudioEncoderSink
- AudioDecoderSink interface; NativeAudioDecoder (JNI decode → AudioTrack)
- ReceiverCastService: swap to NativeAudioDecoder when negotiated codec is Opus/Speex
- SfuRelayGate: PREVIEW_ENABLED=true; add API_BASE, WS_PATH, healthUrl()
- Unit tests: OpusAudioEncoderSinkTest, SpeexAudioEncoderSinkTest, SfuRelayGateTest (19 pass)

Co-authored-by: Cursor <cursoragent@cursor.com>

ndk/jni/speex_bridge.c

@@ -3,23 +3,258 @@
 /*********************************************************************
  * speex_bridge.c
  * Created at: Sun 17 May 2026 22:49:49 +0200
- * Updated at: Wed 20 May 2026 15:17:13 +0200 by Anton Afanasyeu <a.afanasieff@gmail.com>
- * Commit: 5d8e82d2e60a21fff3138d2a394ee4e8b4c6dcb8
+ * Updated at: Sun 28 Jun 2026 22:00:00 +0200 by Anton Afanasyeu <a.afanasieff@gmail.com>
  * Contributors:
- *    - Anton Afanasyeu <a.afanasieff@gmail.com> (2 commits, 21 lines)
+ *    - Anton Afanasyeu <a.afanasieff@gmail.com>
  *    - Cursor Agent (project assistant)
- * Digest: SHA256	5085e4a255dcad08ac2eb746ad1d1f64408a191f035d9a6ca83dab896b3e9a09
-**********************************************************************/
+ **********************************************************************/
 #include <jni.h>
+#include <stdlib.h>
+#include <string.h>
+#include <android/log.h>
+
+#define LOG_TAG "SpeexBridge"
+#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__)
+#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,  LOG_TAG, __VA_ARGS__)
 
 #ifndef ANDROIDCAST_HAVE_SPEEX
 #define ANDROIDCAST_HAVE_SPEEX 0
 #endif
 
+#if ANDROIDCAST_HAVE_SPEEX
+#include <speex/speex.h>
+#include <speex/speex_header.h>
+
+#define SPEEX_ENC_MAGIC 0x53505845L /* SPXE */
+#define SPEEX_DEC_MAGIC 0x53505844L /* SPXD */
+
+/* Speex frame sizes per mode:
+ *   narrowband  (8 kHz): 160 samples/frame
+ *   wideband   (16 kHz): 320 samples/frame
+ *   ultra-wide (32 kHz): 640 samples/frame */
+
+typedef struct {
+    unsigned long  magic;
+    void          *state;
+    SpeexBits      bits;
+    int            sample_rate;
+    int            frame_size;     /* samples per frame */
+    int            encoded_bytes;  /* bytes per encoded frame */
+} SpeexEncCtx;
+
+typedef struct {
+    unsigned long  magic;
+    void          *state;
+    SpeexBits      bits;
+    int            sample_rate;
+    int            frame_size;
+} SpeexDecCtx;
+
+static SpeexEncCtx *enc_from_handle(jlong h) {
+    if (h == 0) return NULL;
+    SpeexEncCtx *ctx = (SpeexEncCtx *)(intptr_t)h;
+    if (ctx->magic != SPEEX_ENC_MAGIC) return NULL;
+    return ctx;
+}
+
+static SpeexDecCtx *dec_from_handle(jlong h) {
+    if (h == 0) return NULL;
+    SpeexDecCtx *ctx = (SpeexDecCtx *)(intptr_t)h;
+    if (ctx->magic != SPEEX_DEC_MAGIC) return NULL;
+    return ctx;
+}
+
+static const SpeexMode *mode_for_rate(int sr) {
+    if (sr <= 8000)  return &speex_nb_mode;
+    if (sr <= 16000) return &speex_wb_mode;
+    return &speex_uwb_mode;
+}
+#endif /* ANDROIDCAST_HAVE_SPEEX */
+
+/* ── availability probe ───────────────────────────────────────────── */
+
 JNIEXPORT jboolean JNICALL
 Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeIsSpeexAvailable(
         JNIEnv *env, jclass clazz) {
-    (void)env;
-    (void)clazz;
+    (void)env; (void)clazz;
     return ANDROIDCAST_HAVE_SPEEX ? JNI_TRUE : JNI_FALSE;
 }
+
+/* ── encoder ────────────────────────────────────────────────────────── */
+
+JNIEXPORT jlong JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexEncoderCreate(
+        JNIEnv *env, jclass clazz, jint sampleRate, jint quality) {
+    (void)env; (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    const SpeexMode *mode = mode_for_rate(sampleRate);
+    void *state = speex_encoder_init(mode);
+    if (!state) { LOGE("speex_encoder_init failed"); return 0L; }
+
+    int q = (quality >= 1 && quality <= 10) ? quality : 8;
+    speex_encoder_ctl(state, SPEEX_SET_QUALITY, &q);
+
+    /* quality 8 wideband → ~15 kbps */
+    int frame_size = 0;
+    speex_encoder_ctl(state, SPEEX_GET_FRAME_SIZE, &frame_size);
+
+    SpeexEncCtx *ctx = (SpeexEncCtx *)calloc(1, sizeof(SpeexEncCtx));
+    if (!ctx) { speex_encoder_destroy(state); return 0L; }
+    ctx->magic       = SPEEX_ENC_MAGIC;
+    ctx->state       = state;
+    ctx->sample_rate = sampleRate;
+    ctx->frame_size  = frame_size;
+    speex_bits_init(&ctx->bits);
+    /* Estimate encoded size: ~38 bytes for quality-8 wideband frame */
+    ctx->encoded_bytes = 64;
+    LOGI("encoder created sr=%d fs=%d q=%d", sampleRate, frame_size, q);
+    return (jlong)(intptr_t)ctx;
+#else
+    (void)sampleRate; (void)quality;
+    return 0L;
+#endif
+}
+
+JNIEXPORT jbyteArray JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexEncode(
+        JNIEnv *env, jclass clazz,
+        jlong handle, jbyteArray pcm16le, jint length) {
+    (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    SpeexEncCtx *ctx = enc_from_handle(handle);
+    if (!ctx || pcm16le == NULL || length <= 0) return NULL;
+
+    jbyte *pcm_bytes = (*env)->GetByteArrayElements(env, pcm16le, NULL);
+    if (!pcm_bytes) return NULL;
+
+    speex_bits_reset(&ctx->bits);
+    speex_encode_int(ctx->state, (spx_int16_t *)pcm_bytes, &ctx->bits);
+    (*env)->ReleaseByteArrayElements(env, pcm16le, pcm_bytes, JNI_ABORT);
+
+    int nbytes = speex_bits_nbytes(&ctx->bits);
+    unsigned char *buf = (unsigned char *)malloc(nbytes);
+    if (!buf) return NULL;
+    speex_bits_write(&ctx->bits, (char *)buf, nbytes);
+
+    jbyteArray result = (*env)->NewByteArray(env, nbytes);
+    if (result) {
+        (*env)->SetByteArrayRegion(env, result, 0, nbytes, (jbyte *)buf);
+    }
+    free(buf);
+    return result;
+#else
+    (void)handle; (void)pcm16le; (void)length;
+    return NULL;
+#endif
+}
+
+JNIEXPORT void JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexEncoderRelease(
+        JNIEnv *env, jclass clazz, jlong handle) {
+    (void)env; (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    SpeexEncCtx *ctx = enc_from_handle(handle);
+    if (!ctx) return;
+    speex_bits_destroy(&ctx->bits);
+    speex_encoder_destroy(ctx->state);
+    ctx->magic = 0;
+    free(ctx);
+#else
+    (void)handle;
+#endif
+}
+
+JNIEXPORT jint JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexEncoderGetFrameSize(
+        JNIEnv *env, jclass clazz, jlong handle) {
+    (void)env; (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    SpeexEncCtx *ctx = enc_from_handle(handle);
+    return ctx ? ctx->frame_size : 0;
+#else
+    (void)handle; return 0;
+#endif
+}
+
+/* ── decoder ────────────────────────────────────────────────────────── */
+
+JNIEXPORT jlong JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexDecoderCreate(
+        JNIEnv *env, jclass clazz, jint sampleRate) {
+    (void)env; (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    const SpeexMode *mode = mode_for_rate(sampleRate);
+    void *state = speex_decoder_init(mode);
+    if (!state) { LOGE("speex_decoder_init failed"); return 0L; }
+
+    int enh = 1;
+    speex_decoder_ctl(state, SPEEX_SET_ENH, &enh);
+
+    int frame_size = 0;
+    speex_decoder_ctl(state, SPEEX_GET_FRAME_SIZE, &frame_size);
+
+    SpeexDecCtx *ctx = (SpeexDecCtx *)calloc(1, sizeof(SpeexDecCtx));
+    if (!ctx) { speex_decoder_destroy(state); return 0L; }
+    ctx->magic       = SPEEX_DEC_MAGIC;
+    ctx->state       = state;
+    ctx->sample_rate = sampleRate;
+    ctx->frame_size  = frame_size;
+    speex_bits_init(&ctx->bits);
+    LOGI("decoder created sr=%d fs=%d", sampleRate, frame_size);
+    return (jlong)(intptr_t)ctx;
+#else
+    (void)sampleRate;
+    return 0L;
+#endif
+}
+
+JNIEXPORT jbyteArray JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexDecode(
+        JNIEnv *env, jclass clazz,
+        jlong handle, jbyteArray speex_data, jint length) {
+    (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    SpeexDecCtx *ctx = dec_from_handle(handle);
+    if (!ctx) return NULL;
+
+    jbyte *in_bytes = NULL;
+    if (speex_data != NULL && length > 0) {
+        in_bytes = (*env)->GetByteArrayElements(env, speex_data, NULL);
+        speex_bits_read_from(&ctx->bits, (char *)in_bytes, length);
+    } else {
+        /* PLC: feed 0 bytes to trigger packet loss concealment */
+        speex_bits_reset(&ctx->bits);
+    }
+
+    spx_int16_t pcm_buf[640]; /* max uwb frame */
+    speex_decode_int(ctx->state, in_bytes ? &ctx->bits : NULL, pcm_buf);
+
+    if (in_bytes) (*env)->ReleaseByteArrayElements(env, speex_data, in_bytes, JNI_ABORT);
+
+    int pcm_bytes = ctx->frame_size * 2; /* 16-bit mono */
+    jbyteArray result = (*env)->NewByteArray(env, pcm_bytes);
+    if (result) {
+        (*env)->SetByteArrayRegion(env, result, 0, pcm_bytes, (jbyte *)pcm_buf);
+    }
+    return result;
+#else
+    (void)handle; (void)speex_data; (void)length;
+    return NULL;
+#endif
+}
+
+JNIEXPORT void JNICALL
+Java_com_foxx_androidcast_media_codec_jni_NativeCodecBridge_nativeSpeexDecoderRelease(
+        JNIEnv *env, jclass clazz, jlong handle) {
+    (void)env; (void)clazz;
+#if ANDROIDCAST_HAVE_SPEEX
+    SpeexDecCtx *ctx = dec_from_handle(handle);
+    if (!ctx) return;
+    speex_bits_destroy(&ctx->bits);
+    speex_decoder_destroy(ctx->state);
+    ctx->magic = 0;
+    free(ctx);
+#else
+    (void)handle;
+#endif
+}