[android] Support BUFFER_FLAG_DECODE_ONLY (#6813)

jasonzhangxx · web-flow · commit 9c4102d0b94f · 2025-09-10T10:05:35.000-07:00
Set flag MediaCodec.BUFFER_FLAG_DECODE_ONLY for decoding only video buffers when tunneling playback is enabled. The change is part of the [PR/5642](youtube/cobalt#5642) from MTK. Bug: 417273879 Bug: 306236129
diff --git a/cobalt/android/apk/app/src/main/java/dev/cobalt/media/MediaCodecBridge.java b/cobalt/android/apk/app/src/main/java/dev/cobalt/media/MediaCodecBridge.java
@@ -62,8 +62,10 @@ class MediaCodecBridge {
   private static final String KEY_CROP_TOP = "crop-top";
 
   private final Object mNativeBridgeLock = new Object();
+
   @GuardedBy("mNativeBridgeLock")
   private long mNativeMediaCodecBridge;
+
   private final SynchronizedHolder<MediaCodec, IllegalStateException> mMediaCodec =
       new SynchronizedHolder<>(() -> new IllegalStateException("MediaCodec was destroyed"));
 
@@ -290,9 +292,7 @@ private String errorMessage() {
   }
 
   public MediaCodecBridge(
-      long nativeMediaCodecBridge,
-      MediaCodec mediaCodec,
-      int tunnelModeAudioSessionId) {
+      long nativeMediaCodecBridge, MediaCodec mediaCodec, int tunnelModeAudioSessionId) {
     if (mediaCodec == null) {
       throw new IllegalArgumentException();
     }
@@ -400,6 +400,15 @@ public static boolean isFrameRenderedCallbackEnabled() {
     return Build.VERSION.SDK_INT >= 34;
   }
 
+  private boolean isDecodeOnlyFlagEnabled() {
+    // Right now, we only enable BUFFER_FLAG_DECODE_ONLY for tunneling playback.
+    if (!mIsTunnelingPlayback) {
+      return false;
+    }
+    // BUFFER_FLAG_DECODE_ONLY is added in Android 14.
+    return Build.VERSION.SDK_INT >= 34;
+  }
+
   @CalledByNative
   public static void createVideoMediaCodecBridge(
       long nativeMediaCodecBridge,
@@ -466,10 +475,7 @@ public static void createVideoMediaCodecBridge(
     }
 
     MediaCodecBridge bridge =
-        new MediaCodecBridge(
-            nativeMediaCodecBridge,
-            mediaCodec,
-            tunnelModeAudioSessionId);
+        new MediaCodecBridge(nativeMediaCodecBridge, mediaCodec, tunnelModeAudioSessionId);
     MediaFormat mediaFormat =
         createVideoDecoderFormat(mime, widthHint, heightHint, videoCapabilities);
 
@@ -739,9 +745,14 @@ private ByteBuffer getOutputBuffer(int index) {
 
   @CalledByNative
   private int queueInputBuffer(
-      int index, int offset, int size, long presentationTimeUs, int flags) {
+      int index, int offset, int size, long presentationTimeUs, int flags, boolean is_decode_only) {
     resetLastPresentationTimeIfNeeded(presentationTimeUs);
     try {
+      if (isDecodeOnlyFlagEnabled()
+          && is_decode_only
+          && (flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) == 0) {
+        flags |= MediaCodec.BUFFER_FLAG_DECODE_ONLY;
+      }
       mMediaCodec.get().queueInputBuffer(index, offset, size, presentationTimeUs, flags);
     } catch (Exception e) {
       Log.e(TAG, "Failed to queue input buffer", e);
@@ -762,7 +773,8 @@ private int queueSecureInputBuffer(
       int cipherMode,
       int blocksToEncrypt,
       int blocksToSkip,
-      long presentationTimeUs) {
+      long presentationTimeUs,
+      boolean is_decode_only) {
     resetLastPresentationTimeIfNeeded(presentationTimeUs);
     try {
       CryptoInfo cryptoInfo = new CryptoInfo();
@@ -776,7 +788,14 @@ private int queueSecureInputBuffer(
         return MediaCodecStatus.ERROR;
       }
 
-      mMediaCodec.get().queueSecureInputBuffer(index, offset, cryptoInfo, presentationTimeUs, 0);
+      int flags = 0;
+      if (isDecodeOnlyFlagEnabled() && is_decode_only) {
+        flags |= MediaCodec.BUFFER_FLAG_DECODE_ONLY;
+      }
+
+      mMediaCodec
+          .get()
+          .queueSecureInputBuffer(index, offset, cryptoInfo, presentationTimeUs, flags);
     } catch (MediaCodec.CryptoException e) {
       int errorCode = e.getErrorCode();
       if (errorCode == MediaCodec.CryptoException.ERROR_NO_KEY) {
@@ -1043,7 +1062,10 @@ private int getAudioFormat(int channelCount) {
   @NativeMethods
   interface Natives {
     void onMediaCodecError(
-        long nativeMediaCodecBridge, boolean isRecoverable, boolean isTransient, String diagnosticInfo);
+        long nativeMediaCodecBridge,
+        boolean isRecoverable,
+        boolean isTransient,
+        String diagnosticInfo);
 
     void onMediaCodecInputBufferAvailable(long nativeMediaCodecBridge, int bufferIndex);
 
diff --git a/starboard/android/shared/audio_decoder.h b/starboard/android/shared/audio_decoder.h
@@ -73,6 +73,10 @@ class AudioDecoder
   void RefreshOutputFormat(MediaCodecBridge* media_codec_bridge) override;
   bool Tick(MediaCodecBridge* media_codec_bridge) override { return false; }
   void OnFlushing() override {}
+  bool IsBufferDecodeOnly(
+      const scoped_refptr<InputBuffer>& input_buffer) override {
+    return false;
+  }
 
   void ReportError(SbPlayerError error, const std::string& error_message);
 
diff --git a/starboard/android/shared/media_codec_bridge.cc b/starboard/android/shared/media_codec_bridge.cc
@@ -324,18 +324,20 @@ jint MediaCodecBridge::QueueInputBuffer(jint index,
                                         jint offset,
                                         jint size,
                                         jlong presentation_time_microseconds,
-                                        jint flags) {
+                                        jint flags,
+                                        jboolean is_decode_only) {
   JNIEnv* env = AttachCurrentThread();
   return Java_MediaCodecBridge_queueInputBuffer(
       env, j_media_codec_bridge_, index, offset, size,
-      presentation_time_microseconds, flags);
+      presentation_time_microseconds, flags, is_decode_only);
 }
 
 jint MediaCodecBridge::QueueSecureInputBuffer(
     jint index,
     jint offset,
     const SbDrmSampleInfo& drm_sample_info,
-    jlong presentation_time_microseconds) {
+    jlong presentation_time_microseconds,
+    jboolean is_decode_only) {
   JNIEnv* env = AttachCurrentThread();
 
   ScopedJavaLocalRef<jbyteArray> j_iv =
@@ -371,7 +373,7 @@ jint MediaCodecBridge::QueueSecureInputBuffer(
   return Java_MediaCodecBridge_queueSecureInputBuffer(
       env, j_media_codec_bridge_, index, offset, j_iv, j_key_id, j_clear_bytes,
       j_encrypted_bytes, subsample_count, cipher_mode, blocks_to_encrypt,
-      blocks_to_skip, presentation_time_microseconds);
+      blocks_to_skip, presentation_time_microseconds, is_decode_only);
 }
 
 ScopedJavaLocalRef<jobject> MediaCodecBridge::GetOutputBuffer(jint index) {
diff --git a/starboard/android/shared/media_codec_bridge.h b/starboard/android/shared/media_codec_bridge.h
@@ -185,11 +185,13 @@ class MediaCodecBridge {
                         jint offset,
                         jint size,
                         jlong presentation_time_microseconds,
-                        jint flags);
+                        jint flags,
+                        jboolean is_decode_only);
   jint QueueSecureInputBuffer(jint index,
                               jint offset,
                               const SbDrmSampleInfo& drm_sample_info,
-                              jlong presentation_time_microseconds);
+                              jlong presentation_time_microseconds,
+                              jboolean is_decode_only);
 
   // It is the responsibility of the client to manage the lifetime of the
   // jobject that |GetOutputBuffer| returns.
diff --git a/starboard/android/shared/media_decoder.cc b/starboard/android/shared/media_decoder.cc
@@ -517,23 +517,24 @@ bool MediaDecoder::ProcessOneInputBuffer(
     // should wait until it's initialized to avoid errors.
     status = MEDIA_CODEC_NO_KEY;
   } else if (pending_input.type == PendingInput::kWriteCodecConfig) {
-    status = media_codec_bridge_->QueueInputBuffer(dequeue_input_result.index,
-                                                   kNoOffset, size, kNoPts,
-                                                   BUFFER_FLAG_CODEC_CONFIG);
+    status = media_codec_bridge_->QueueInputBuffer(
+        dequeue_input_result.index, kNoOffset, size, kNoPts,
+        BUFFER_FLAG_CODEC_CONFIG, false);
   } else if (pending_input.type == PendingInput::kWriteInputBuffer) {
     jlong pts_us = input_buffer->timestamp();
     if (drm_system_ && input_buffer->drm_info()) {
       status = media_codec_bridge_->QueueSecureInputBuffer(
           dequeue_input_result.index, kNoOffset, *input_buffer->drm_info(),
-          pts_us);
+          pts_us, host_->IsBufferDecodeOnly(input_buffer));
     } else {
       status = media_codec_bridge_->QueueInputBuffer(
-          dequeue_input_result.index, kNoOffset, size, pts_us, kNoBufferFlags);
+          dequeue_input_result.index, kNoOffset, size, pts_us, kNoBufferFlags,
+          host_->IsBufferDecodeOnly(input_buffer));
     }
   } else {
-    status = media_codec_bridge_->QueueInputBuffer(dequeue_input_result.index,
-                                                   kNoOffset, size, kNoPts,
-                                                   BUFFER_FLAG_END_OF_STREAM);
+    status = media_codec_bridge_->QueueInputBuffer(
+        dequeue_input_result.index, kNoOffset, size, kNoPts,
+        BUFFER_FLAG_END_OF_STREAM, false);
     host_->OnEndOfStreamWritten(media_codec_bridge_.get());
   }
 
diff --git a/starboard/android/shared/media_decoder.h b/starboard/android/shared/media_decoder.h
@@ -71,6 +71,9 @@ class MediaDecoder final
     // before the MediaCodecBridge is flushed.
     virtual void OnFlushing() = 0;
 
+    virtual bool IsBufferDecodeOnly(
+        const scoped_refptr<InputBuffer>& input_buffer) = 0;
+
    protected:
     ~Host() {}
   };
diff --git a/starboard/android/shared/video_decoder.cc b/starboard/android/shared/video_decoder.cc
@@ -973,6 +973,16 @@ void VideoDecoder::OnFlushing() {
   decoder_status_cb_(kReleaseAllFrames, NULL);
 }
 
+bool VideoDecoder::IsBufferDecodeOnly(
+    const scoped_refptr<InputBuffer>& input_buffer) {
+  if (!is_video_frame_tracker_enabled_) {
+    return false;
+  }
+
+  SB_CHECK(video_frame_tracker_);
+  return input_buffer->timestamp() < video_frame_tracker_->seek_to_time();
+}
+
 namespace {
 
 void updateTexImage(jobject surface_texture) {
diff --git a/starboard/android/shared/video_decoder.h b/starboard/android/shared/video_decoder.h
@@ -117,6 +117,8 @@ class VideoDecoder
   void RefreshOutputFormat(MediaCodecBridge* media_codec_bridge) override;
   bool Tick(MediaCodecBridge* media_codec_bridge) override;
   void OnFlushing() override;
+  bool IsBufferDecodeOnly(
+      const scoped_refptr<InputBuffer>& input_buffer) override;
 
   void TryToSignalPrerollForTunnelMode();
   bool IsFrameRenderedCallbackEnabled();
