Android improvements.

Start/Stop receiving stream method for VideoTrack (#25)

Properly remove observer upon deconstruction (#26)

feat: Expose setCodecPreferences/getCapabilities for android. (#61)

fix: add WrappedVideoDecoderFactory.java. (#74)

Co-authored-by: davidliu <davidliu@deviange.net>

api/media_stream_interface.cc

@@ -19,6 +19,10 @@ const char* const MediaStreamTrackInterface::kVideoKind =
 const char* const MediaStreamTrackInterface::kAudioKind =
     cricket::kMediaTypeAudio;
 
+bool VideoTrackInterface::should_receive() const {
+  return true;
+}
+
 VideoTrackInterface::ContentHint VideoTrackInterface::content_hint() const {
   return ContentHint::kNone;
 }

api/media_stream_interface.h

@@ -188,6 +188,8 @@ class RTC_EXPORT VideoTrackInterface
 
   virtual VideoTrackSourceInterface* GetSource() const = 0;
 
+  virtual void set_should_receive(bool should_receive) {}
+  virtual bool should_receive() const;
   virtual ContentHint content_hint() const;
   virtual void set_content_hint(ContentHint hint) {}
 

media/base/media_channel.h

@@ -1002,6 +1002,8 @@ class VideoMediaReceiveChannelInterface : public MediaReceiveChannelInterface {
                                              webrtc::RtcpMode rtcp_mode,
                                              absl::optional<int> rtx_time) = 0;
   virtual bool AddDefaultRecvStreamForTesting(const StreamParams& sp) = 0;
+  virtual void StartReceive(uint32_t ssrc) {}
+  virtual void StopReceive(uint32_t ssrc) {}
 };
 
 }  // namespace cricket

media/engine/webrtc_video_engine.cc

@@ -3500,6 +3500,24 @@ void WebRtcVideoReceiveChannel::WebRtcVideoReceiveStream::SetReceiverParameters(
   }
 }
 
+void WebRtcVideoReceiveChannel::StartReceive(uint32_t ssrc) {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  WebRtcVideoReceiveStream* stream = FindReceiveStream(ssrc);
+  if(!stream) {
+    return;
+  }
+  stream->StartReceiveStream();
+}
+
+void WebRtcVideoReceiveChannel::StopReceive(uint32_t ssrc) {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  WebRtcVideoReceiveStream* stream = FindReceiveStream(ssrc);
+  if(!stream) {
+    return;
+  }
+  stream->StopReceiveStream();
+}
+
 void WebRtcVideoReceiveChannel::WebRtcVideoReceiveStream::
     RecreateReceiveStream() {
   RTC_DCHECK_RUN_ON(&thread_checker_);

media/engine/webrtc_video_engine.h

@@ -632,7 +632,8 @@ class WebRtcVideoReceiveChannel : public MediaChannelUtil,
                                      bool nack_enabled,
                                      webrtc::RtcpMode rtcp_mode,
                                      absl::optional<int> rtx_time) override;
-
+  void StartReceive(uint32_t ssrc) override;
+  void StopReceive(uint32_t ssrc) override;
  private:
   class WebRtcVideoReceiveStream;
   struct ChangedReceiverParameters {

pc/media_stream_track_proxy.h

@@ -55,6 +55,8 @@ PROXY_SECONDARY_METHOD2(void,
 PROXY_SECONDARY_METHOD1(void, RemoveSink, rtc::VideoSinkInterface<VideoFrame>*)
 PROXY_SECONDARY_METHOD0(void, RequestRefreshFrame)
 BYPASS_PROXY_CONSTMETHOD0(VideoTrackSourceInterface*, GetSource)
+PROXY_CONSTMETHOD0(bool, should_receive)
+PROXY_METHOD1(void, set_should_receive, bool)
 
 PROXY_METHOD1(void, RegisterObserver, ObserverInterface*)
 PROXY_METHOD1(void, UnregisterObserver, ObserverInterface*)

pc/video_rtp_receiver.cc

@@ -41,15 +41,20 @@ VideoRtpReceiver::VideoRtpReceiver(
           rtc::Thread::Current(),
           worker_thread,
           VideoTrack::Create(receiver_id, source_, worker_thread))),
-      attachment_id_(GenerateUniqueId()) {
+      cached_track_should_receive_(track_->should_receive()),
+      attachment_id_(GenerateUniqueId()),
+      worker_thread_safety_(PendingTaskSafetyFlag::CreateDetachedInactive()) {
   RTC_DCHECK(worker_thread_);
   SetStreams(streams);
+  track_->RegisterObserver(this);
   RTC_DCHECK_EQ(source_->state(), MediaSourceInterface::kInitializing);
 }
 
 VideoRtpReceiver::~VideoRtpReceiver() {
   RTC_DCHECK_RUN_ON(&signaling_thread_checker_);
   RTC_DCHECK(!media_channel_);
+
+  track_->UnregisterObserver(this);
 }
 
 std::vector<std::string> VideoRtpReceiver::stream_ids() const {
@@ -114,6 +119,39 @@ void VideoRtpReceiver::Stop() {
   track_->internal()->set_ended();
 }
 
+void VideoRtpReceiver::OnChanged() {
+  RTC_DCHECK_RUN_ON(&signaling_thread_checker_);
+  if (cached_track_should_receive_ != track_->should_receive()) {
+    cached_track_should_receive_ = track_->should_receive();
+    worker_thread_->PostTask(
+        [this, receive = cached_track_should_receive_]() {
+          RTC_DCHECK_RUN_ON(worker_thread_);
+          if(receive) {
+            StartMediaChannel();
+          } else {
+            StopMediaChannel();
+          }
+        });
+  }
+}
+
+void VideoRtpReceiver::StartMediaChannel() {  
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  if (!media_channel_) {
+    return;
+  }
+  media_channel_->StartReceive(signaled_ssrc_.value_or(0));
+  OnGenerateKeyFrame();
+}
+
+void VideoRtpReceiver::StopMediaChannel() {
+  RTC_DCHECK_RUN_ON(worker_thread_);
+  if (!media_channel_) {
+    return;
+  }
+  media_channel_->StopReceive(signaled_ssrc_.value_or(0));
+}
+
 void VideoRtpReceiver::RestartMediaChannel(absl::optional<uint32_t> ssrc) {
   RTC_DCHECK_RUN_ON(&signaling_thread_checker_);
   MediaSourceInterface::SourceState state = source_->state();
@@ -209,6 +247,7 @@ void VideoRtpReceiver::set_transport(
 void VideoRtpReceiver::SetStreams(
     const std::vector<rtc::scoped_refptr<MediaStreamInterface>>& streams) {
   RTC_DCHECK_RUN_ON(&signaling_thread_checker_);
+
   // Remove remote track from any streams that are going away.
   for (const auto& existing_stream : streams_) {
     bool removed = true;

pc/video_rtp_receiver.h

@@ -42,7 +42,8 @@
 
 namespace webrtc {
 
-class VideoRtpReceiver : public RtpReceiverInternal {
+class VideoRtpReceiver : public RtpReceiverInternal,
+                         public ObserverInterface {
  public:
   // An SSRC of 0 will create a receiver that will match the first SSRC it
   // sees. Must be called on signaling thread.
@@ -60,6 +61,9 @@ class VideoRtpReceiver : public RtpReceiverInternal {
 
   rtc::scoped_refptr<VideoTrackInterface> video_track() const { return track_; }
 
+  // ObserverInterface implementation
+  void OnChanged() override;
+
   // RtpReceiverInterface implementation
   rtc::scoped_refptr<MediaStreamTrackInterface> track() const override {
     return track_;
@@ -115,6 +119,8 @@ class VideoRtpReceiver : public RtpReceiverInternal {
                          cricket::MediaReceiveChannelInterface* media_channel);
 
  private:
+  void StartMediaChannel();
+  void StopMediaChannel();
   void RestartMediaChannel(absl::optional<uint32_t> ssrc)
       RTC_RUN_ON(&signaling_thread_checker_);
   void RestartMediaChannel_w(absl::optional<uint32_t> ssrc,
@@ -162,6 +168,8 @@ class VideoRtpReceiver : public RtpReceiverInternal {
       RTC_GUARDED_BY(&signaling_thread_checker_) = nullptr;
   bool received_first_packet_ RTC_GUARDED_BY(&signaling_thread_checker_) =
       false;
+
+  bool cached_track_should_receive_ RTC_GUARDED_BY(&signaling_thread_checker_);
   const int attachment_id_;
   rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor_
       RTC_GUARDED_BY(worker_thread_);
@@ -177,6 +185,7 @@ class VideoRtpReceiver : public RtpReceiverInternal {
   // or switched.
   bool saved_generate_keyframe_ RTC_GUARDED_BY(worker_thread_) = false;
   bool saved_encoded_sink_enabled_ RTC_GUARDED_BY(worker_thread_) = false;
+  const rtc::scoped_refptr<PendingTaskSafetyFlag> worker_thread_safety_;
 };
 
 }  // namespace webrtc

pc/video_track.cc

@@ -76,6 +76,19 @@ VideoTrackSourceInterface* VideoTrack::GetSourceInternal() const {
   return video_source_->internal();
 }
 
+void VideoTrack::set_should_receive(bool receive) {
+  RTC_DCHECK_RUN_ON(&signaling_thread_);
+  if (should_receive_ == receive)
+    return;
+  should_receive_ = receive;
+  Notifier<VideoTrackInterface>::FireOnChanged();
+}
+
+bool VideoTrack::should_receive() const {
+  RTC_DCHECK_RUN_ON(&signaling_thread_);
+  return should_receive_;
+}
+
 VideoTrackInterface::ContentHint VideoTrack::content_hint() const {
   RTC_DCHECK_RUN_ON(&signaling_thread_);
   return content_hint_;

pc/video_track.h

@@ -48,6 +48,9 @@ class VideoTrack : public MediaStreamTrack<VideoTrackInterface>,
   void RequestRefreshFrame() override;
   VideoTrackSourceInterface* GetSource() const override;
 
+  void set_should_receive(bool should_receive) override;
+  bool should_receive() const override;
+
   ContentHint content_hint() const override;
   void set_content_hint(ContentHint hint) override;
   bool set_enabled(bool enable) override;
@@ -81,6 +84,7 @@ class VideoTrack : public MediaStreamTrack<VideoTrackInterface>,
   // be queried without blocking on the worker thread by callers that don't
   // use an api proxy to call the `enabled()` method.
   bool enabled_w_ RTC_GUARDED_BY(worker_thread_) = true;
+  bool should_receive_ RTC_GUARDED_BY(signaling_thread_) = true;
 };
 
 }  // namespace webrtc

sdk/android/BUILD.gn

@@ -367,6 +367,7 @@ if (is_android) {
     sources = [
       "api/org/webrtc/DefaultVideoDecoderFactory.java",
       "api/org/webrtc/DefaultVideoEncoderFactory.java",
+      "api/org/webrtc/WrappedVideoDecoderFactory.java",
     ]
 
     deps = [

sdk/android/api/org/webrtc/PeerConnectionFactory.java

@@ -20,6 +20,7 @@
 import org.webrtc.RtpCapabilities;
 import org.webrtc.audio.AudioDeviceModule;
 import org.webrtc.audio.JavaAudioDeviceModule;
+import org.webrtc.RtpCapabilities;
 
 /**
  * Java wrapper for a C++ PeerConnectionFactoryInterface.  Main entry point to

sdk/android/api/org/webrtc/VideoTrack.java

@@ -54,6 +54,24 @@ public void removeSink(VideoSink sink) {
     }
   }
 
+  /**
+   * For a remote video track, starts/stops receiving the video stream.
+   * 
+   * If this is a local video track, this is a no-op.
+   */
+  public void setShouldReceive(boolean shouldReceive){
+    nativeSetShouldReceive(getNativeMediaStreamTrack(), shouldReceive);
+  }
+
+  /**
+   * The current receive status for a remote video track.
+   * 
+   * This has no meaning for a local video track.
+   */
+  public boolean shouldReceive(){
+    return nativeGetShouldReceive(getNativeMediaStreamTrack());
+  }
+
   @Override
   public void dispose() {
     for (long nativeSink : sinks.values()) {
@@ -73,4 +91,6 @@ public long getNativeVideoTrack() {
   private static native void nativeRemoveSink(long track, long nativeSink);
   private static native long nativeWrapSink(VideoSink sink);
   private static native void nativeFreeSink(long sink);
+  private static native void nativeSetShouldReceive(long track, boolean shouldReceive);
+  private static native boolean nativeGetShouldReceive(long track);
 }

sdk/android/api/org/webrtc/WrappedVideoDecoderFactory.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2023 LiveKit
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.webrtc;
+
+import android.media.MediaCodecInfo;
+import androidx.annotation.Nullable;
+
+import java.util.Arrays;
+import java.util.LinkedHashSet;
+
+public class WrappedVideoDecoderFactory implements VideoDecoderFactory {
+    public WrappedVideoDecoderFactory(@Nullable EglBase.Context eglContext) {
+        this.hardwareVideoDecoderFactory = new HardwareVideoDecoderFactory(eglContext);
+        this.platformSoftwareVideoDecoderFactory = new PlatformSoftwareVideoDecoderFactory(eglContext);
+    }
+
+    private final VideoDecoderFactory hardwareVideoDecoderFactory;
+    private final VideoDecoderFactory hardwareVideoDecoderFactoryWithoutEglContext = new HardwareVideoDecoderFactory(null)   ;
+    private final VideoDecoderFactory softwareVideoDecoderFactory = new SoftwareVideoDecoderFactory();
+    @Nullable
+    private final VideoDecoderFactory platformSoftwareVideoDecoderFactory;
+
+    @Override
+    public VideoDecoder createDecoder(VideoCodecInfo codecType) {
+        VideoDecoder softwareDecoder = this.softwareVideoDecoderFactory.createDecoder(codecType);
+        VideoDecoder hardwareDecoder = this.hardwareVideoDecoderFactory.createDecoder(codecType);
+        if (softwareDecoder == null && this.platformSoftwareVideoDecoderFactory != null) {
+            softwareDecoder = this.platformSoftwareVideoDecoderFactory.createDecoder(codecType);
+        }
+
+        if(hardwareDecoder != null && disableSurfaceTextureFrame(hardwareDecoder.getImplementationName())) {
+            hardwareDecoder.release();
+            hardwareDecoder = this.hardwareVideoDecoderFactoryWithoutEglContext.createDecoder(codecType);
+        }
+
+        if (hardwareDecoder != null && softwareDecoder != null) {
+            return new VideoDecoderFallback(softwareDecoder, hardwareDecoder);
+        } else {
+            return hardwareDecoder != null ? hardwareDecoder : softwareDecoder;
+        }
+    }
+
+    private boolean disableSurfaceTextureFrame(String name) {
+        if (name.startsWith("OMX.qcom.") || name.startsWith("OMX.hisi.")) {
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public VideoCodecInfo[] getSupportedCodecs() {
+        LinkedHashSet<VideoCodecInfo> supportedCodecInfos = new LinkedHashSet();
+        supportedCodecInfos.addAll(Arrays.asList(this.softwareVideoDecoderFactory.getSupportedCodecs()));
+        supportedCodecInfos.addAll(Arrays.asList(this.hardwareVideoDecoderFactory.getSupportedCodecs()));
+        if (this.platformSoftwareVideoDecoderFactory != null) {
+            supportedCodecInfos.addAll(Arrays.asList(this.platformSoftwareVideoDecoderFactory.getSupportedCodecs()));
+        }
+
+        return (VideoCodecInfo[])supportedCodecInfos.toArray(new VideoCodecInfo[supportedCodecInfos.size()]);
+    }
+}

sdk/android/src/jni/pc/peer_connection_factory.cc

@@ -32,6 +32,7 @@
 #include "sdk/android/src/jni/logging/log_sink.h"
 #include "sdk/android/src/jni/pc/android_network_monitor.h"
 #include "sdk/android/src/jni/pc/audio.h"
+#include "sdk/android/src/jni/pc/rtp_capabilities.h"
 #include "sdk/android/src/jni/pc/ice_candidate.h"
 #include "sdk/android/src/jni/pc/media_stream_track.h"
 #include "sdk/android/src/jni/pc/owned_factory_and_threads.h"

sdk/android/src/jni/video_track.cc

@@ -44,5 +44,16 @@ static void JNI_VideoTrack_FreeSink(JNIEnv* jni, jlong j_native_sink) {
   delete reinterpret_cast<rtc::VideoSinkInterface<VideoFrame>*>(j_native_sink);
 }
 
+static void JNI_VideoTrack_SetShouldReceive(JNIEnv* jni,
+                                      jlong j_native_track,
+                                      jboolean should_receive) {
+  reinterpret_cast<VideoTrackInterface*>(j_native_track)->set_should_receive(should_receive);
+}
+
+static jboolean JNI_VideoTrack_GetShouldReceive(JNIEnv* jni,
+                                      jlong j_native_track) {
+  return reinterpret_cast<VideoTrackInterface*>(j_native_track)->should_receive();
+}
+
 }  // namespace jni
 }  // namespace webrtc

sdk/objc/api/peerconnection/RTCVideoTrack.h

@@ -25,6 +25,9 @@ RTC_OBJC_EXPORT
 /** The video source for this video track. */
 @property(nonatomic, readonly) RTC_OBJC_TYPE(RTCVideoSource) *source;
 
+/** The receive state, if this is a remote video track. */
+@property(nonatomic, assign) BOOL shouldReceive;
+
 - (instancetype)init NS_UNAVAILABLE;
 
 /** Register a renderer that will render all frames received on this track. */