[media] FFmpegDemuxer: Detect seek failures

Previously the result from av_seek_frame() was ignored. In the (rare)
case of a seek failure, this allowed demuxing to continue from the
previous location while trying to render from the seek location,
resulting in a confused UI state.

With this change, seek failures result in playback error.

Bug: 1424380
Change-Id: I6d5d80f5bb5132900c153db22a0079e76f074568
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4416363
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1130101}

media/filters/ffmpeg_demuxer.cc

@@ -1064,7 +1064,7 @@ void FFmpegDemuxer::Seek(base::TimeDelta time, PipelineStatusCallback cb) {
   DCHECK(!pending_seek_cb_);
   TRACE_EVENT_ASYNC_BEGIN0("media", "FFmpegDemuxer::Seek", this);
   pending_seek_cb_ = std::move(cb);
-  SeekInternal(time, base::BindOnce(&FFmpegDemuxer::OnSeekFrameSuccess,
+  SeekInternal(time, base::BindOnce(&FFmpegDemuxer::OnSeekFrameDone,
                                     weak_factory_.GetWeakPtr()));
 }
 
@@ -1073,7 +1073,7 @@ bool FFmpegDemuxer::IsSeekable() const {
 }
 
 void FFmpegDemuxer::SeekInternal(base::TimeDelta time,
-                                 base::OnceClosure seek_cb) {
+                                 base::OnceCallback<void(int)> seek_cb) {
   DCHECK(task_runner_->RunsTasksInCurrentSequence());
 
   // FFmpeg requires seeks to be adjusted according to the lowest starting time.
@@ -1115,10 +1115,10 @@ void FFmpegDemuxer::SeekInternal(base::TimeDelta time,
   const AVStream* seeking_stream = demux_stream->av_stream();
   DCHECK(seeking_stream);
 
-  blocking_task_runner_->PostTaskAndReply(
+  blocking_task_runner_->PostTaskAndReplyWithResult(
       FROM_HERE,
-      base::BindOnce(base::IgnoreResult(&av_seek_frame),
-                     glue_->format_context(), seeking_stream->index,
+      base::BindOnce(&av_seek_frame, glue_->format_context(),
+                     seeking_stream->index,
                      ConvertToTimeBase(seeking_stream->time_base, seek_time),
                      // Always seek to a timestamp <= to the desired timestamp.
                      AVSEEK_FLAG_BACKWARD),
@@ -1656,7 +1656,7 @@ FFmpegDemuxerStream* FFmpegDemuxer::FindPreferredStreamForSeeking(
   return nullptr;
 }
 
-void FFmpegDemuxer::OnSeekFrameSuccess() {
+void FFmpegDemuxer::OnSeekFrameDone(int result) {
   DCHECK(task_runner_->RunsTasksInCurrentSequence());
   DCHECK(pending_seek_cb_);
 
@@ -1666,6 +1666,12 @@ void FFmpegDemuxer::OnSeekFrameSuccess() {
     return;
   }
 
+  if (result < 0) {
+    MEDIA_LOG(ERROR, media_log_) << GetDisplayName() << ": demuxer seek failed";
+    RunPendingSeekCB(PIPELINE_ERROR_READ);
+    return;
+  }
+
   // Tell streams to flush buffers due to seeking.
   for (const auto& stream : streams_) {
     if (stream)
@@ -1729,8 +1735,10 @@ void FFmpegDemuxer::OnEnabledAudioTracksChanged(
 
 void FFmpegDemuxer::OnVideoSeekedForTrackChange(
     DemuxerStream* video_stream,
-    base::OnceClosure seek_completed_cb) {
+    base::OnceClosure seek_completed_cb,
+    int result) {
   static_cast<FFmpegDemuxerStream*>(video_stream)->FlushBuffers(true);
+  // TODO(crbug.com/1424380): Report seek failures for track changes too.
   std::move(seek_completed_cb).Run();
 }
 

media/filters/ffmpeg_demuxer.h

@@ -304,7 +304,7 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   FFmpegDemuxerStream* FindPreferredStreamForSeeking(base::TimeDelta seek_time);
 
   // FFmpeg callbacks during seeking.
-  void OnSeekFrameSuccess();
+  void OnSeekFrameDone(int result);
 
   // FFmpeg callbacks during reading + helper method to initiate reads.
   void ReadFrameIfNeeded();
@@ -334,9 +334,11 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
 
   void SetLiveness(StreamLiveness liveness);
 
-  void SeekInternal(base::TimeDelta time, base::OnceClosure seek_cb);
+  void SeekInternal(base::TimeDelta time,
+                    base::OnceCallback<void(int)> seek_cb);
   void OnVideoSeekedForTrackChange(DemuxerStream* video_stream,
-                                   base::OnceClosure seek_completed_cb);
+                                   base::OnceClosure seek_completed_cb,
+                                   int result);
   void SeekOnVideoTrackChange(base::TimeDelta seek_to_time,
                               TrackChangeCB seek_completed_cb,
                               DemuxerStream::Type stream_type,