media/gpu/video_encode_accelerator_tests: Fix the timing of FlushDoneTask()...

media/gpu/video_encode_accelerator_tests: Fix the timing of FlushDoneTask() when VEA doesn't support Flush()

When VideoEncodeAccelerator (VEA) doesn't support Flush(),
VideoEncoderClient simulates the Flush() flow. VideoEncoderClient
starts the Flush event when the last frame is fed to VEA.
VideoEncoderClient, however, invokes FlushDoneEvent() when the
VEA read the last frame. This may be before the encoded bitstream
of the last frame is returned by BitstreamBufferReady().
This not only breaks VEA API rule; FlushDoneTask() is called
after the encoded bitstream of the last frame is returned, but
also BitstreamBufferProcessors may process less number of frames
than expected.
This CL fixes the timing of FlushDoneTask().

Bug: b:159384004, 1045825
Test: video_encode_accelerator_tests on hana
Change-Id: I47e3bc39699a727f5bdb9ccc0043dc2bd096fa6d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2340853
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: David Staessens <dstaessens@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798001}

media/gpu/test/video_encoder/video_encoder_client.cc

@@ -279,6 +279,24 @@ void VideoEncoderClient::BitstreamBufferReady(
     bitstream_processor_->ProcessBitstream(bitstream_ref, frame_index_);
   }
   frame_index_++;
+  FlushDoneTaskIfNeeded();
+}
+
+void VideoEncoderClient::FlushDoneTaskIfNeeded() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(encoder_client_sequence_checker_);
+  // If the encoder does not support flushing, we have to manually call
+  // FlushDoneTask(). Invoke FlushDoneTask() when
+  // 1.) Flush is not supported by VideoEncodeAccelerator,
+  // 2.) all the frames have been returned and
+  // 3.) bitstreams of all the video frames have been output.
+  // This is only valid if we always flush at the end of the stream (not in a
+  // middle of the stream), which is the case in all of our test cases.
+  if (!encoder_->IsFlushSupported() &&
+      encoder_client_state_ == VideoEncoderClientState::kFlushing &&
+      frame_index_ == encoder_client_config_.num_frames_to_encode &&
+      num_outstanding_encode_requests_ == 0) {
+    FlushDoneTask(true);
+  }
 }
 
 void VideoEncoderClient::BitstreamBufferProcessed(int32_t bitstream_buffer_id) {
@@ -355,7 +373,6 @@ void VideoEncoderClient::EncodeTask() {
 void VideoEncoderClient::EncodeNextFrameTask() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(encoder_client_sequence_checker_);
   DVLOGF(4);
-
   // Stop encoding frames if we're no longer in the encoding state.
   if (encoder_client_state_ != VideoEncoderClientState::kEncoding)
     return;
@@ -391,15 +408,12 @@ void VideoEncoderClient::EncodeNextFrameTask() {
 void VideoEncoderClient::FlushTask() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(encoder_client_sequence_checker_);
   DVLOGF(4);
-
   // Changing the state to flushing will abort any pending encodes.
   encoder_client_state_ = VideoEncoderClientState::kFlushing;
 
-  // If the encoder does not support flush, immediately consider flushing done.
   if (!encoder_->IsFlushSupported()) {
     FireEvent(VideoEncoder::EncoderEvent::kFlushing);
-    if (num_outstanding_encode_requests_ == 0)
-      FlushDoneTask(true);
+    FlushDoneTaskIfNeeded();
     return;
   }
 
@@ -430,14 +444,7 @@ void VideoEncoderClient::EncodeDoneTask(base::TimeDelta timestamp) {
   FireEvent(VideoEncoder::EncoderEvent::kFrameReleased);
 
   num_outstanding_encode_requests_--;
-
-  // If the encoder does not support flushing, we have to manually call
-  // FlushDoneTask() when the last outstanding encode has been completed.
-  if ((encoder_client_state_ == VideoEncoderClientState::kFlushing) &&
-      !encoder_->IsFlushSupported() &&
-      (num_outstanding_encode_requests_ == 0)) {
-    FlushDoneTask(true);
-  }
+  FlushDoneTaskIfNeeded();
 
   // Queue the next frame to be encoded.
   encoder_client_task_runner_->PostTask(

media/gpu/test/video_encoder/video_encoder_client.h

@@ -169,6 +169,9 @@ class VideoEncoderClient : public VideoEncodeAccelerator::Client {
   void EncodeDoneTask(base::TimeDelta timestamp);
   // Called by the encoder when flushing has completed.
   void FlushDoneTask(bool success);
+  // Calls FlushDoneTask() if needed. This is necessary if Flush() flow is
+  // simulated because VEA doesn't support Flush().
+  void FlushDoneTaskIfNeeded();
 
   // Fire the specified event.
   void FireEvent(VideoEncoder::EncoderEvent event);