Introduce media::TimeSource.

media/filters/audio_renderer_impl.cc

Index: media/filters/audio_renderer_impl.cc
diff --git a/media/filters/audio_renderer_impl.cc b/media/filters/audio_renderer_impl.cc
index ae4096a9de0377ef34bd44acfad78026d2c152fe..e1e46df5cb6a9e7d6b7fcf987ff6817d0d177e01 100644
--- a/media/filters/audio_renderer_impl.cc
+++ b/media/filters/audio_renderer_impl.cc
@@ -72,7 +72,7 @@ AudioRendererImpl::~AudioRendererImpl() {
   DCHECK(!algorithm_.get());
 }
 
-void AudioRendererImpl::StartRendering() {
+void AudioRendererImpl::StartTicking() {
   DVLOG(1) << __FUNCTION__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!rendering_);
@@ -102,7 +102,7 @@ void AudioRendererImpl::StartRendering_Locked() {
   sink_->Play();
 }
 
-void AudioRendererImpl::StopRendering() {
+void AudioRendererImpl::StopTicking() {
   DVLOG(1) << __FUNCTION__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(rendering_);
@@ -206,7 +206,6 @@ void AudioRendererImpl::Stop(const base::Closure& callback) {
 
     ChangeState_Locked(kStopped);
     algorithm_.reset();
-    time_cb_.Reset();
     flush_cb_.Reset();
   }
 
@@ -218,8 +217,8 @@ void AudioRendererImpl::Stop(const base::Closure& callback) {
   audio_buffer_stream_.Stop(callback);
 }
 
-void AudioRendererImpl::StartPlayingFrom(base::TimeDelta timestamp) {
-  DVLOG(1) << __FUNCTION__ << "(" << timestamp.InMicroseconds() << ")";
+void AudioRendererImpl::StartPlaying() {
+  DVLOG(1) << __FUNCTION__;
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   base::AutoLock auto_lock(lock_);
@@ -229,15 +228,30 @@ void AudioRendererImpl::StartPlayingFrom(base::TimeDelta timestamp) {
   DCHECK(!pending_read_) << "Pending read must complete before seeking";
 
   ChangeState_Locked(kPlaying);
+  AttemptRead_Locked();
+}
+
+void AudioRendererImpl::SetMediaTimestamp(base::TimeDelta timestamp) {
+  DVLOG(1) << __FUNCTION__ << "(" << timestamp.InMicroseconds() << ")";
+  DCHECK(!rendering_);
   start_timestamp_ = timestamp;
+}
 
-  AttemptRead_Locked();
+base::TimeDelta AudioRendererImpl::CurrentMediaTimestamp() {
+  DVLOG(1) << __FUNCTION__;
+  DCHECK(task_runner_->BelongsToCurrentThread());
+
+  // TODO(scherkus): Take time since last updating |audio_clock_| into account.

[xhwang, 2014/07/12 06:36:44]

Yeah, this will improve time accuracy, also solve the "audio shorter than video"
issue.

+  base::AutoLock auto_lock(lock_);
+  base::TimeDelta timestamp = audio_clock_->CurrentMediaTimestamp();
+  if (timestamp == kNoTimestamp())
+    return start_timestamp_;
+  return timestamp;
 }
 
 void AudioRendererImpl::Initialize(DemuxerStream* stream,
                                    const PipelineStatusCB& init_cb,
                                    const StatisticsCB& statistics_cb,
-                                   const TimeCB& time_cb,
                                    const BufferingStateCB& buffering_state_cb,
                                    const base::Closure& ended_cb,
                                    const PipelineStatusCB& error_cb) {
@@ -246,7 +260,6 @@ void AudioRendererImpl::Initialize(DemuxerStream* stream,
   DCHECK_EQ(stream->type(), DemuxerStream::AUDIO);
   DCHECK(!init_cb.is_null());
   DCHECK(!statistics_cb.is_null());
-  DCHECK(!time_cb.is_null());
   DCHECK(!buffering_state_cb.is_null());
   DCHECK(!ended_cb.is_null());
   DCHECK(!error_cb.is_null());
@@ -256,7 +269,6 @@ void AudioRendererImpl::Initialize(DemuxerStream* stream,
   state_ = kInitializing;
 
   init_cb_ = init_cb;
-  time_cb_ = time_cb;
   buffering_state_cb_ = buffering_state_cb;
   ended_cb_ = ended_cb;
   error_cb_ = error_cb;
@@ -552,7 +564,6 @@ int AudioRendererImpl::Render(AudioBus* audio_bus,
   const int delay_frames = static_cast<int>(playback_delay.InSecondsF() *
                                             audio_parameters_.sample_rate());
   int frames_written = 0;
-  base::Closure time_cb;
   {
     base::AutoLock auto_lock(lock_);
 
@@ -586,8 +597,6 @@ int AudioRendererImpl::Render(AudioBus* audio_bus,
     //   3) We are in the kPlaying state
     //
     // Otherwise the buffer has data we can send to the device.
-    const base::TimeDelta media_timestamp_before_filling =
-        audio_clock_->CurrentMediaTimestamp();
     if (algorithm_->frames_buffered() > 0) {
       frames_written = algorithm_->FillBuffer(audio_bus, requested_frames);
       audio_clock_->WroteAudio(
@@ -614,21 +623,8 @@ int AudioRendererImpl::Render(AudioBus* audio_bus,
                              base::Bind(&AudioRendererImpl::AttemptRead,
                                         weak_factory_.GetWeakPtr()));
     }
-
-    // We only want to execute |time_cb_| if time has progressed and we haven't
-    // signaled end of stream yet.
-    if (media_timestamp_before_filling !=
-            audio_clock_->CurrentMediaTimestamp() &&
-        !rendered_end_of_stream_) {
-      time_cb = base::Bind(time_cb_,
-                           audio_clock_->CurrentMediaTimestamp(),
-                           audio_clock_->last_endpoint_timestamp());
-    }
   }
 
-  if (!time_cb.is_null())
-    task_runner_->PostTask(FROM_HERE, time_cb);
-
   DCHECK_LE(frames_written, requested_frames);
   return frames_written;
 }