add RTCRtpSender.generateKeyFrame

defined in
  https://w3c.github.io/webrtc-encoded-transform/#rtcrtpsender-extension

Note: this does not implement the "rid(s)" parameter which will be done in a future CL.

VP8 still synchronizes keyframes on all layers even when asked for ones on individual layers while H264 (when implemented as three different encoders in SimulcastEncoderAdapter) can actually utilize this.

This does not change the behavior when receiving a RTCP PLI for a particular layer.

BUG=chromium:1354101

Change-Id: Ic8b14d155242e32c9aeafa55fe6652f346ac76b8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/274169
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#38472}
diff --git a/api/rtp_sender_interface.h b/api/rtp_sender_interface.h
index 500bd25..6fc658f 100644
--- a/api/rtp_sender_interface.h
+++ b/api/rtp_sender_interface.h
@@ -104,6 +104,9 @@
       std::unique_ptr<VideoEncoderFactory::EncoderSelectorInterface>
           encoder_selector) = 0;
 
+  // TODO(crbug.com/1354101): make pure virtual again after Chrome roll.
+  virtual RTCError GenerateKeyFrame() { return RTCError::OK(); }
+
  protected:
   ~RtpSenderInterface() override = default;
 };
diff --git a/call/video_send_stream.h b/call/video_send_stream.h
index 3a3ccce0..be6aa4a 100644
--- a/call/video_send_stream.h
+++ b/call/video_send_stream.h
@@ -252,6 +252,8 @@
 
   virtual Stats GetStats() = 0;
 
+  virtual void GenerateKeyFrame() = 0;
+
  protected:
   virtual ~VideoSendStream() {}
 };
diff --git a/media/base/fake_media_engine.cc b/media/base/fake_media_engine.cc
index 7692efe..60f158e 100644
--- a/media/base/fake_media_engine.cc
+++ b/media/base/fake_media_engine.cc
@@ -427,7 +427,8 @@
 void FakeVideoMediaChannel::ClearRecordableEncodedFrameCallback(uint32_t ssrc) {
 }
 
-void FakeVideoMediaChannel::GenerateKeyFrame(uint32_t ssrc) {}
+void FakeVideoMediaChannel::RequestRecvKeyFrame(uint32_t ssrc) {}
+void FakeVideoMediaChannel::GenerateSendKeyFrame(uint32_t ssrc) {}
 
 FakeVoiceEngine::FakeVoiceEngine() : fail_create_channel_(false) {
   // Add a fake audio codec. Note that the name must not be "" as there are
diff --git a/media/base/fake_media_engine.h b/media/base/fake_media_engine.h
index 55c85d7..b98a2da 100644
--- a/media/base/fake_media_engine.h
+++ b/media/base/fake_media_engine.h
@@ -462,7 +462,8 @@
       std::function<void(const webrtc::RecordableEncodedFrame&)> callback)
       override;
   void ClearRecordableEncodedFrameCallback(uint32_t ssrc) override;
-  void GenerateKeyFrame(uint32_t ssrc) override;
+  void RequestRecvKeyFrame(uint32_t ssrc) override;
+  void GenerateSendKeyFrame(uint32_t ssrc) override;
 
  private:
   bool SetRecvCodecs(const std::vector<VideoCodec>& codecs);
diff --git a/media/base/media_channel.h b/media/base/media_channel.h
index 924e862..ef90484 100644
--- a/media/base/media_channel.h
+++ b/media/base/media_channel.h
@@ -921,8 +921,11 @@
       std::function<void(const webrtc::RecordableEncodedFrame&)> callback) = 0;
   // Clear recordable encoded frame callback for `ssrc`
   virtual void ClearRecordableEncodedFrameCallback(uint32_t ssrc) = 0;
-  // Cause generation of a keyframe for `ssrc`
-  virtual void GenerateKeyFrame(uint32_t ssrc) = 0;
+  // Request generation of a keyframe for `ssrc` on a receiving channel via
+  // RTCP feedback.
+  virtual void RequestRecvKeyFrame(uint32_t ssrc) = 0;
+  // Cause generation of a keyframe for `ssrc` on a sending channel.
+  virtual void GenerateSendKeyFrame(uint32_t ssrc) = 0;
 
   virtual std::vector<webrtc::RtpSource> GetSources(uint32_t ssrc) const = 0;
 };
diff --git a/media/engine/fake_webrtc_call.h b/media/engine/fake_webrtc_call.h
index 311e35a..65ee0d5 100644
--- a/media/engine/fake_webrtc_call.h
+++ b/media/engine/fake_webrtc_call.h
@@ -194,6 +194,7 @@
   rtc::VideoSourceInterface<webrtc::VideoFrame>* source() const {
     return source_;
   }
+  void GenerateKeyFrame() override {}
 
  private:
   // rtc::VideoSinkInterface<VideoFrame> implementation.
diff --git a/media/engine/webrtc_video_engine.cc b/media/engine/webrtc_video_engine.cc
index 80c2267..714cb67 100644
--- a/media/engine/webrtc_video_engine.cc
+++ b/media/engine/webrtc_video_engine.cc
@@ -2827,6 +2827,16 @@
   }
 }
 
+void WebRtcVideoChannel::WebRtcVideoSendStream::GenerateKeyFrame() {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  if (stream_ != NULL) {
+    stream_->GenerateKeyFrame();
+  } else {
+    RTC_LOG(LS_WARNING)
+        << "Absent send stream; ignoring request to generate keyframe.";
+  }
+}
+
 WebRtcVideoChannel::WebRtcVideoReceiveStream::WebRtcVideoReceiveStream(
     WebRtcVideoChannel* channel,
     webrtc::Call* call,
@@ -3551,11 +3561,11 @@
   }
 }
 
-void WebRtcVideoChannel::GenerateKeyFrame(uint32_t ssrc) {
+void WebRtcVideoChannel::RequestRecvKeyFrame(uint32_t ssrc) {
   RTC_DCHECK_RUN_ON(&thread_checker_);
   WebRtcVideoReceiveStream* stream = FindReceiveStream(ssrc);
   if (stream) {
-    stream->GenerateKeyFrame();
+    return stream->GenerateKeyFrame();
   } else {
     RTC_LOG(LS_ERROR)
         << "Absent receive stream; ignoring key frame generation for ssrc "
@@ -3563,6 +3573,18 @@
   }
 }
 
+void WebRtcVideoChannel::GenerateSendKeyFrame(uint32_t ssrc) {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  auto it = send_streams_.find(ssrc);
+  if (it != send_streams_.end()) {
+    it->second->GenerateKeyFrame();
+  } else {
+    RTC_LOG(LS_ERROR)
+        << "Absent send stream; ignoring key frame generation for ssrc "
+        << ssrc;
+  }
+}
+
 void WebRtcVideoChannel::SetEncoderToPacketizerFrameTransformer(
     uint32_t ssrc,
     rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer) {
diff --git a/media/engine/webrtc_video_engine.h b/media/engine/webrtc_video_engine.h
index d87a612..a0150a8 100644
--- a/media/engine/webrtc_video_engine.h
+++ b/media/engine/webrtc_video_engine.h
@@ -248,7 +248,8 @@
       std::function<void(const webrtc::RecordableEncodedFrame&)> callback)
       override;
   void ClearRecordableEncodedFrameCallback(uint32_t ssrc) override;
-  void GenerateKeyFrame(uint32_t ssrc) override;
+  void RequestRecvKeyFrame(uint32_t ssrc) override;
+  void GenerateSendKeyFrame(uint32_t ssrc) override;
 
   void SetEncoderToPacketizerFrameTransformer(
       uint32_t ssrc,
@@ -390,6 +391,7 @@
     void SetEncoderToPacketizerFrameTransformer(
         rtc::scoped_refptr<webrtc::FrameTransformerInterface>
             frame_transformer);
+    void GenerateKeyFrame();
 
    private:
     // Parameters needed to reconstruct the underlying stream.
diff --git a/pc/rtp_sender.cc b/pc/rtp_sender.cc
index 753ac2f..98e86b3 100644
--- a/pc/rtp_sender.cc
+++ b/pc/rtp_sender.cc
@@ -596,6 +596,13 @@
   return dtmf_sender_proxy_;
 }
 
+RTCError AudioRtpSender::GenerateKeyFrame() {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  RTC_DLOG(LS_ERROR) << "Tried to get generate a key frame for audio.";
+  return RTCError(RTCErrorType::UNSUPPORTED_OPERATION,
+                  "Generating key frames for audio is not supported.");
+}
+
 void AudioRtpSender::SetSend() {
   RTC_DCHECK_RUN_ON(signaling_thread_);
   RTC_DCHECK(!stopped_);
@@ -686,6 +693,18 @@
   return nullptr;
 }
 
+RTCError VideoRtpSender::GenerateKeyFrame() {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  if (video_media_channel() && ssrc_ && !stopped_) {
+    worker_thread_->PostTask(
+        [&] { video_media_channel()->GenerateSendKeyFrame(ssrc_); });
+  } else {
+    RTC_LOG(LS_WARNING) << "Tried to generate key frame for sender that is "
+                           "stopped or has no media channel.";
+  }
+  return RTCError::OK();
+}
+
 void VideoRtpSender::SetSend() {
   RTC_DCHECK_RUN_ON(signaling_thread_);
   RTC_DCHECK(!stopped_);
diff --git a/pc/rtp_sender.h b/pc/rtp_sender.h
index e3cd12f..2cfa08d 100644
--- a/pc/rtp_sender.h
+++ b/pc/rtp_sender.h
@@ -351,6 +351,7 @@
   }
 
   rtc::scoped_refptr<DtmfSenderInterface> GetDtmfSender() const override;
+  RTCError GenerateKeyFrame() override;
 
  protected:
   AudioRtpSender(rtc::Thread* worker_thread,
@@ -410,6 +411,7 @@
   }
 
   rtc::scoped_refptr<DtmfSenderInterface> GetDtmfSender() const override;
+  RTCError GenerateKeyFrame() override;
 
   RTCError CheckSVCParameters(const RtpParameters& parameters) override;
 
diff --git a/pc/rtp_sender_proxy.h b/pc/rtp_sender_proxy.h
index 140b5ff..376fd29 100644
--- a/pc/rtp_sender_proxy.h
+++ b/pc/rtp_sender_proxy.h
@@ -48,6 +48,7 @@
 PROXY_METHOD1(void,
               SetEncoderSelector,
               std::unique_ptr<VideoEncoderFactory::EncoderSelectorInterface>)
+PROXY_METHOD0(RTCError, GenerateKeyFrame)
 END_PROXY_MAP(RtpSender)
 
 }  // namespace webrtc
diff --git a/pc/video_rtp_receiver.cc b/pc/video_rtp_receiver.cc
index e01a33f..098ffde 100644
--- a/pc/video_rtp_receiver.cc
+++ b/pc/video_rtp_receiver.cc
@@ -279,7 +279,7 @@
   if (media_channel_) {
     if (saved_generate_keyframe_) {
       // TODO(bugs.webrtc.org/8694): Stop using 0 to mean unsignalled SSRC
-      media_channel_->GenerateKeyFrame(ssrc_.value_or(0));
+      media_channel_->RequestRecvKeyFrame(ssrc_.value_or(0));
       saved_generate_keyframe_ = false;
     }
     if (encoded_sink_enabled) {
@@ -331,7 +331,7 @@
     return;
   }
   // TODO(bugs.webrtc.org/8694): Stop using 0 to mean unsignalled SSRC
-  media_channel_->GenerateKeyFrame(ssrc_.value_or(0));
+  media_channel_->RequestRecvKeyFrame(ssrc_.value_or(0));
   // We need to remember to request generation of a new key frame if the media
   // channel changes, because there's no feedback whether the keyframe
   // generation has completed on the channel.
diff --git a/pc/video_rtp_receiver_unittest.cc b/pc/video_rtp_receiver_unittest.cc
index 4019879..c266459 100644
--- a/pc/video_rtp_receiver_unittest.cc
+++ b/pc/video_rtp_receiver_unittest.cc
@@ -49,7 +49,8 @@
                 ClearRecordableEncodedFrameCallback,
                 (uint32_t),
                 (override));
-    MOCK_METHOD(void, GenerateKeyFrame, (uint32_t), (override));
+    MOCK_METHOD(void, RequestRecvKeyFrame, (uint32_t), (override));
+    MOCK_METHOD(void, GenerateSendKeyFrame, (uint32_t), (override));
   };
 
   class MockVideoSink : public rtc::VideoSinkInterface<RecordableEncodedFrame> {
@@ -96,7 +97,7 @@
 }
 
 TEST_F(VideoRtpReceiverTest, GeneratesKeyFrame) {
-  EXPECT_CALL(channel_, GenerateKeyFrame(0));
+  EXPECT_CALL(channel_, RequestRecvKeyFrame(0));
   Source()->GenerateKeyFrame();
 }
 
@@ -105,17 +106,17 @@
   // A channel switch without previous call to GenerateKeyFrame shouldn't
   // cause a call to happen on the new channel.
   MockVideoMediaChannel channel2(nullptr, cricket::VideoOptions());
-  EXPECT_CALL(channel_, GenerateKeyFrame).Times(0);
-  EXPECT_CALL(channel2, GenerateKeyFrame).Times(0);
+  EXPECT_CALL(channel_, RequestRecvKeyFrame).Times(0);
+  EXPECT_CALL(channel2, RequestRecvKeyFrame).Times(0);
   SetMediaChannel(&channel2);
   Mock::VerifyAndClearExpectations(&channel2);
 
   // Generate a key frame. When we switch channel next time, we will have to
   // re-generate it as we don't know if it was eventually received
-  EXPECT_CALL(channel2, GenerateKeyFrame).Times(1);
+  EXPECT_CALL(channel2, RequestRecvKeyFrame).Times(1);
   Source()->GenerateKeyFrame();
   MockVideoMediaChannel channel3(nullptr, cricket::VideoOptions());
-  EXPECT_CALL(channel3, GenerateKeyFrame);
+  EXPECT_CALL(channel3, RequestRecvKeyFrame);
   SetMediaChannel(&channel3);
 
   // Switching to a new channel should now not cause calls to GenerateKeyFrame.
diff --git a/video/video_send_stream.cc b/video/video_send_stream.cc
index b259998..f245332 100644
--- a/video/video_send_stream.cc
+++ b/video/video_send_stream.cc
@@ -343,5 +343,11 @@
   send_stream_.DeliverRtcp(packet, length);
 }
 
+void VideoSendStream::GenerateKeyFrame() {
+  if (video_stream_encoder_) {
+    video_stream_encoder_->SendKeyFrame();
+  }
+}
+
 }  // namespace internal
 }  // namespace webrtc
diff --git a/video/video_send_stream.h b/video/video_send_stream.h
index 5b4323d..a776373 100644
--- a/video/video_send_stream.h
+++ b/video/video_send_stream.h
@@ -93,6 +93,7 @@
 
   void StopPermanentlyAndGetRtpStates(RtpStateMap* rtp_state_map,
                                       RtpPayloadStateMap* payload_state_map);
+  void GenerateKeyFrame() override;
 
  private:
   friend class test::VideoSendStreamPeer;