Disable AV sync in non kModeSyncPts modes

In the ignore PTS modes, the frames will have no PTS or may have wrong
PTS, so we should disable AV sync which can't function without that.

BUG= b/109900155
TEST=Manual

Change-Id: Id3b762054638f41bbbb8df002ff1a12da533e258
Reviewed-on: https://chromium-review.googlesource.com/1092162Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Commit-Queue: Mina Almasry <almasrymina@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566032}

chromecast/media/cma/backend/media_pipeline_backend_for_mixer.cc

@@ -41,7 +41,7 @@ MediaPipelineBackendForMixer::CreateAudioDecoder() {
   if (audio_decoder_)
     return nullptr;
   audio_decoder_ = std::make_unique<AudioDecoderForMixer>(this);
-  if (video_decoder_ && !av_sync_) {
+  if (video_decoder_ && !av_sync_ && !IsIgnorePtsMode()) {
     av_sync_ = AvSync::Create(GetTaskRunner(), this);
   }
   return audio_decoder_.get();
@@ -54,7 +54,7 @@ MediaPipelineBackendForMixer::CreateVideoDecoder() {
     return nullptr;
   video_decoder_ = VideoDecoderForMixer::Create(params_);
   DCHECK(video_decoder_.get());
-  if (audio_decoder_ && !av_sync_) {
+  if (audio_decoder_ && !av_sync_ && !IsIgnorePtsMode()) {
     av_sync_ = AvSync::Create(GetTaskRunner(), this);
   }
   return video_decoder_.get();
@@ -74,7 +74,7 @@ bool MediaPipelineBackendForMixer::Initialize() {
 bool MediaPipelineBackendForMixer::Start(int64_t start_pts) {
   DCHECK_EQ(kStateInitialized, state_);
   int64_t start_playback_timestamp_us = INT64_MIN;
-  if (params_.sync_type == MediaPipelineDeviceParams::kModeSyncPts) {
+  if (!IsIgnorePtsMode()) {
     start_playback_timestamp_us =
         MonotonicClockNow() + kSyncedPlaybackStartDelayUs;
   }
@@ -183,5 +183,12 @@ int64_t MediaPipelineBackendForMixer::MonotonicClockNow() const {
 }
 #endif
 
+bool MediaPipelineBackendForMixer::IsIgnorePtsMode() const {
+  return params_.sync_type ==
+             MediaPipelineDeviceParams::MediaSyncType::kModeIgnorePts ||
+         params_.sync_type ==
+             MediaPipelineDeviceParams::MediaSyncType::kModeIgnorePtsAndVSync;
+}
+
 }  // namespace media
 }  // namespace chromecast

chromecast/media/cma/backend/media_pipeline_backend_for_mixer.h

@@ -67,6 +67,8 @@ class MediaPipelineBackendForMixer : public MediaPipelineBackend {
   };
   State state_;
 
+  bool IsIgnorePtsMode() const;
+
   const MediaPipelineDeviceParams params_;
 
   std::unique_ptr<AvSync> av_sync_;