Revert of quest keyframes more frequently on stream start/decoding er…

…ror. (patchset webrtc-uwp#2 id:170001 of https://codereview.webrtc.org/2996823002/ )

Reason for revert:
Causes iOS H264 calls received in the background to have increased delay before being able to decode stream from sender due to not having a keyframe.

Original issue's description:
> Reland of quest keyframes more frequently on stream start/decoding error. (patchset #1 id:1 of https://codereview.chromium.org/2994043002/ )
>
> Reason for revert:
> Create fix CL.
>
> Original issue's description:
> > Revert of Request keyframes more frequently on stream start/decoding error. (patchset #1 id:1 of https://codereview.webrtc.org/2993793002/ )
> >
> > Reason for revert:
> > Broke downstream test that was waiting for 5 keyframes to be received within 10 seconds. Maybe the issue is that "stats_callback_->OnCompleteFrame(frame->num_references == 0, ..." was changed to "frame->is_keyframe()"?
> >
> > Original issue's description:
> > > Request keyframes more frequently on stream start/decoding error.
> > >
> > > In this CL:
> > >  - Added FrameObject::is_keyframe() convinience function.
> > >  - Moved logic to request keyframes on decoding error from VideoReceived to
> > >    VideoReceiveStream.
> > >  - Added keyframe_required as a parameter to FrameBuffer::NextFrame.
> > >
> > > BUG=webrtc:8074
> > >
> > > Review-Url: https://codereview.webrtc.org/2993793002
> > > Cr-Commit-Position: refs/heads/master@{#19280}
> > > Committed: https://chromium.googlesource.com/external/webrtc/+/26b48043581735eed6e36b95fae6f5b1bcf8cfb5
> >
> > [email protected],[email protected],[email protected],[email protected]
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=webrtc:8074
> >
> > Review-Url: https://codereview.webrtc.org/2994043002
> > Cr-Commit-Position: refs/heads/master@{#19295}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/77a983185f57628cd5955bd2c0a1bf71c30439bb
>
> [email protected],[email protected],[email protected],[email protected]
> # Skipping CQ checks because original CL landed less than 1 days ago.
> BUG=webrtc:8074
>
> Review-Url: https://codereview.webrtc.org/2996823002
> Cr-Commit-Position: refs/heads/master@{#19324}
> Committed: https://chromium.googlesource.com/external/webrtc/+/628ac5964e32e66083a6ab14dceac6cb2cabe345

[email protected],[email protected],[email protected],[email protected],[email protected]
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:8074

Review-Url: https://codereview.webrtc.org/2995153002
Cr-Commit-Position: refs/heads/master@{#19392}

webrtc/modules/video_coding/frame_buffer2.cc

@@ -59,8 +59,7 @@ FrameBuffer::~FrameBuffer() {}
 
 FrameBuffer::ReturnReason FrameBuffer::NextFrame(
     int64_t max_wait_time_ms,
-    std::unique_ptr<FrameObject>* frame_out,
-    bool keyframe_required) {
+    std::unique_ptr<FrameObject>* frame_out) {
   TRACE_EVENT0("webrtc", "FrameBuffer::NextFrame");
   int64_t latest_return_time_ms =
       clock_->TimeInMilliseconds() + max_wait_time_ms;
@@ -106,10 +105,6 @@ FrameBuffer::ReturnReason FrameBuffer::NextFrame(
         }
 
         FrameObject* frame = frame_it->second.frame.get();
-
-        if (keyframe_required && !frame->is_keyframe())
-          continue;
-
         next_frame_it_ = frame_it;
         if (frame->RenderTime() == -1)
           frame->SetRenderTime(timing_->RenderTimeMs(frame->timestamp, now_ms));
@@ -284,7 +279,7 @@ int FrameBuffer::InsertFrame(std::unique_ptr<FrameObject> frame) {
   TRACE_EVENT0("webrtc", "FrameBuffer::InsertFrame");
   RTC_DCHECK(frame);
   if (stats_callback_)
-    stats_callback_->OnCompleteFrame(frame->is_keyframe(), frame->size());
+    stats_callback_->OnCompleteFrame(frame->num_references == 0, frame->size());
   FrameKey key(frame->picture_id, frame->spatial_layer);
 
   rtc::CritScope lock(&crit_);
@@ -312,7 +307,7 @@ int FrameBuffer::InsertFrame(std::unique_ptr<FrameObject> frame) {
   if (last_decoded_frame_it_ != frames_.end() &&
       key <= last_decoded_frame_it_->first) {
     if (AheadOf(frame->timestamp, last_decoded_frame_timestamp_) &&
-        frame->is_keyframe()) {
+        frame->num_references == 0) {
       // If this frame has a newer timestamp but an earlier picture id then we
       // assume there has been a jump in the picture id due to some encoder
       // reconfiguration or some other reason. Even though this is not according

webrtc/modules/video_coding/frame_buffer2.h

@@ -57,8 +57,7 @@ class FrameBuffer {
   //    kTimeout.
   //  - If the FrameBuffer is stopped then it will return kStopped.
   ReturnReason NextFrame(int64_t max_wait_time_ms,
-                         std::unique_ptr<FrameObject>* frame_out,
-                         bool keyframe_required = false);
+                         std::unique_ptr<FrameObject>* frame_out);
 
   // Tells the FrameBuffer which protection mode that is in use. Affects
   // the frame timing.

webrtc/modules/video_coding/frame_buffer2_unittest.cc

@@ -168,12 +168,11 @@ class TestFrameBuffer2 : public ::testing::Test {
     return buffer_.InsertFrame(std::move(frame));
   }
 
-  void ExtractFrame(int64_t max_wait_time = 0, bool keyframe_required = false) {
+  void ExtractFrame(int64_t max_wait_time = 0) {
     crit_.Enter();
     if (max_wait_time == 0) {
       std::unique_ptr<FrameObject> frame;
-      FrameBuffer::ReturnReason res =
-          buffer_.NextFrame(0, &frame, keyframe_required);
+      FrameBuffer::ReturnReason res = buffer_.NextFrame(0, &frame);
       if (res != FrameBuffer::ReturnReason::kStopped)
         frames_.emplace_back(std::move(frame));
       crit_.Leave();
@@ -542,18 +541,5 @@ TEST_F(TestFrameBuffer2, InvalidReferences) {
   EXPECT_EQ(2, InsertFrame(2, 0, 3000, false, 1));
 }
 
-TEST_F(TestFrameBuffer2, KeyframeRequired) {
-  EXPECT_EQ(1, InsertFrame(1, 0, 1000, false));
-  EXPECT_EQ(2, InsertFrame(2, 0, 2000, false, 1));
-  EXPECT_EQ(3, InsertFrame(3, 0, 3000, false));
-  ExtractFrame();
-  ExtractFrame(0, true);
-  ExtractFrame();
-
-  CheckFrame(0, 1, 0);
-  CheckFrame(1, 3, 0);
-  CheckNoFrame(2);
-}
-
 }  // namespace video_coding
 }  // namespace webrtc

webrtc/modules/video_coding/frame_object.h

@@ -44,8 +44,6 @@ class FrameObject : public webrtc::VCMEncodedFrame {
 
   size_t size() const { return _length; }
 
-  bool is_keyframe() const { return num_references == 0; }
-
   // The tuple (|picture_id|, |spatial_layer|) uniquely identifies a frame
   // object. For codec types that don't necessarily have picture ids they
   // have to be constructed from the header data relevant to that codec.

webrtc/modules/video_coding/video_receiver.cc

@@ -320,7 +320,24 @@ int32_t VideoReceiver::Decode(const VCMEncodedFrame& frame) {
   if (decoder == nullptr) {
     return VCM_NO_CODEC_REGISTERED;
   }
-  return decoder->Decode(frame, clock_->TimeInMilliseconds());
+  // Decode a frame
+  int32_t ret = decoder->Decode(frame, clock_->TimeInMilliseconds());
+
+  // Check for failed decoding, run frame type request callback if needed.
+  bool request_key_frame = false;
+  if (ret < 0) {
+    request_key_frame = true;
+  }
+
+  if (!frame.Complete() || frame.MissingFrame()) {
+    request_key_frame = true;
+    ret = VCM_OK;
+  }
+  if (request_key_frame) {
+    rtc::CritScope cs(&process_crit_);
+    _scheduleKeyRequest = true;
+  }
+  return ret;
 }
 
 // Register possible receive codecs, can be called multiple times

webrtc/video/video_receive_stream.cc

@@ -497,14 +497,9 @@ void VideoReceiveStream::DecodeThreadFunction(void* ptr) {
 bool VideoReceiveStream::Decode() {
   TRACE_EVENT0("webrtc", "VideoReceiveStream::Decode");
   static const int kMaxWaitForFrameMs = 3000;
-  static const int kMaxWaitForKeyFrameMs = 200;
-
-  int wait_ms = keyframe_required_ ? kMaxWaitForKeyFrameMs : kMaxWaitForFrameMs;
   std::unique_ptr<video_coding::FrameObject> frame;
-  // TODO(philipel): Call NextFrame with |keyframe_required| argument when
-  //                 downstream project has been fixed.
   video_coding::FrameBuffer::ReturnReason res =
-      frame_buffer_->NextFrame(wait_ms, &frame);
+      frame_buffer_->NextFrame(kMaxWaitForFrameMs, &frame);
 
   if (res == video_coding::FrameBuffer::ReturnReason::kStopped) {
     video_receiver_.DecodingStopped();
@@ -513,15 +508,8 @@ bool VideoReceiveStream::Decode() {
 
   if (frame) {
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kFrameFound);
-    if (video_receiver_.Decode(frame.get()) == VCM_OK) {
-      keyframe_required_ = false;
+    if (video_receiver_.Decode(frame.get()) == VCM_OK)
       rtp_video_stream_receiver_.FrameDecoded(frame->picture_id);
-    } else if (keyframe_required_ == false) {
-      keyframe_required_ = true;
-      // TODO(philipel): Remove this keyframe request when downstream project
-      //                 has been fixed.
-      RequestKeyFrame();
-    }
   } else {
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kTimeout);
     int64_t now_ms = clock_->TimeInMilliseconds();
@@ -534,14 +522,15 @@ bool VideoReceiveStream::Decode() {
     // check if we have received a packet within the last 5 seconds.
     bool stream_is_active = last_packet_ms && now_ms - *last_packet_ms < 5000;
 
-    // If we recently have been receiving packets belonging to a keyframe then
-    // we assume a keyframe is currently being received.
+    // If we recently (within |kMaxWaitForFrameMs|) have been receiving packets
+    // belonging to a keyframe then we assume a keyframe is being received right
+    // now.
     bool receiving_keyframe =
         last_keyframe_packet_ms &&
-        now_ms - *last_keyframe_packet_ms < kMaxWaitForKeyFrameMs;
+        now_ms - *last_keyframe_packet_ms < kMaxWaitForFrameMs;
 
     if (stream_is_active && !receiving_keyframe) {
-      LOG(LS_WARNING) << "No decodable frame in " << wait_ms
+      LOG(LS_WARNING) << "No decodable frame in " << kMaxWaitForFrameMs
                       << " ms, requesting keyframe.";
       RequestKeyFrame();
     }

webrtc/video/video_receive_stream.h

@@ -148,10 +148,6 @@ class VideoReceiveStream : public webrtc::VideoReceiveStream,
 
   std::unique_ptr<RtpStreamReceiverInterface> media_receiver_;
   std::unique_ptr<RtpStreamReceiverInterface> rtx_receiver_;
-
-  // Whenever we are in an undecodable state (stream has just started or due to
-  // a decoding error) we require a keyframe to restart the stream.
-  bool keyframe_required_ = true;
 };
 }  // namespace internal
 }  // namespace webrtc