Merge AudioRendererImpl and AudioRendererBase; add NullAudioSink

This CL removes AudioRendererImpl and replaces it with AudioRendererBase.
NullAudioRenderer is also removed and replaced with NullAudioSink.
Also, a subtle bug is fixed in AudioRendererBase to allow for smooth
video playback when running Chrome with the --disable-audio flag.

BUG=119549,116645
TEST=media_unittests, playing video on Chrome/content_shell with and without --disable-audio flag should look identical


Review URL: http://codereview.chromium.org/9826023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@131089 0039d316-1c4b-4281-b951-d872f2087c98

content/content_renderer.gypi

@@ -84,8 +84,6 @@
     'renderer/media/audio_input_message_filter.h',
     'renderer/media/audio_message_filter.cc',
     'renderer/media/audio_message_filter.h',
-    'renderer/media/audio_renderer_impl.cc',
-    'renderer/media/audio_renderer_impl.h',
     'renderer/media/capture_video_decoder.cc',
     'renderer/media/capture_video_decoder.h',
     'renderer/media/media_stream_center.h',

content/content_tests.gypi

@@ -283,7 +283,6 @@
         'renderer/active_notification_tracker_unittest.cc',
         'renderer/gpu/input_event_filter_unittest.cc',
         'renderer/media/audio_message_filter_unittest.cc',
-        'renderer/media/audio_renderer_impl_unittest.cc',
         'renderer/media/capture_video_decoder_unittest.cc',
         'renderer/media/video_capture_impl_unittest.cc',
         'renderer/media/video_capture_message_filter_unittest.cc',

content/renderer/media/audio_device.cc

@@ -69,10 +69,6 @@ void AudioDevice::Initialize(const media::AudioParameters& params,
   CHECK(!callback_);  // Calling Initialize() twice?
 
   audio_parameters_ = params;
-  audio_parameters_.Reset(
-      params.format(),
-      params.channel_layout(), params.sample_rate(), params.bits_per_sample(),
-      params.frames_per_buffer());
   callback_ = callback;
 }
 
@@ -85,7 +81,8 @@ AudioDevice::~AudioDevice() {
 void AudioDevice::Start() {
   DCHECK(callback_) << "Initialize hasn't been called";
   message_loop()->PostTask(FROM_HERE,
-      base::Bind(&AudioDevice::InitializeOnIOThread, this, audio_parameters_));
+      base::Bind(&AudioDevice::CreateStreamOnIOThread, this,
+                 audio_parameters_));
 }
 
 void AudioDevice::Stop() {
@@ -127,7 +124,7 @@ void AudioDevice::GetVolume(double* volume) {
   *volume = volume_;
 }
 
-void AudioDevice::InitializeOnIOThread(const media::AudioParameters& params) {
+void AudioDevice::CreateStreamOnIOThread(const media::AudioParameters& params) {
   DCHECK(message_loop()->BelongsToCurrentThread());
   // Make sure we don't create the stream more than once.
   DCHECK_EQ(0, stream_id_);

content/renderer/media/audio_device.h

@@ -23,7 +23,7 @@
 //
 //            Task [IO thread]                  IPC [IO thread]
 //
-// Start -> InitializeOnIOThread ------> AudioHostMsg_CreateStream -------->
+// Start -> CreateStreamOnIOThread -----> AudioHostMsg_CreateStream ------>
 //       <- OnStreamCreated <- AudioMsg_NotifyStreamCreated <-
 //       ---> PlayOnIOThread -----------> AudioHostMsg_PlayStream -------->
 //
@@ -96,27 +96,11 @@ class CONTENT_EXPORT AudioDevice
 
   virtual void Initialize(const media::AudioParameters& params,
                           RenderCallback* callback) OVERRIDE;
-  // Starts audio playback.
   virtual void Start() OVERRIDE;
-
-  // Stops audio playback.
   virtual void Stop() OVERRIDE;
-
-  // Resumes playback if currently paused.
   virtual void Play() OVERRIDE;
-
-  // Pauses playback.
-  // If |flush| is true then any pending audio that is in the pipeline
-  // (has not yet reached the hardware) will be discarded.  In this case,
-  // when Play() is later called, no previous pending audio will be
-  // rendered.
   virtual void Pause(bool flush) OVERRIDE;
-
-  // Sets the playback volume, with range [0.0, 1.0] inclusive.
-  // Returns |true| on success.
   virtual bool SetVolume(double volume) OVERRIDE;
-
-  // Gets the playback volume, with range [0.0, 1.0] inclusive.
   virtual void GetVolume(double* volume) OVERRIDE;
 
   // Methods called on IO thread ----------------------------------------------
@@ -136,7 +120,7 @@ class CONTENT_EXPORT AudioDevice
   // The following methods are tasks posted on the IO thread that needs to
   // be executed on that thread. They interact with AudioMessageFilter and
   // sends IPC messages on that thread.
-  void InitializeOnIOThread(const media::AudioParameters& params);
+  void CreateStreamOnIOThread(const media::AudioParameters& params);
   void PlayOnIOThread();
   void PauseOnIOThread(bool flush);
   void ShutDownOnIOThread();

content/renderer/media/audio_hardware.cc

@@ -48,36 +48,6 @@ size_t GetOutputBufferSize() {
   return output_buffer_size;
 }
 
-size_t GetHighLatencyOutputBufferSize(int sample_rate) {
-  // TODO(vrk/crogers): The buffer sizes that this function computes is probably
-  // overly conservative. However, reducing the buffer size to 2048-8192 bytes
-  // caused crbug.com/108396. This computation should be revisited while making
-  // sure crbug.com/108396 doesn't happen again.
-
-  // The minimum number of samples in a hardware packet.
-  // This value is selected so that we can handle down to 5khz sample rate.
-  static const size_t kMinSamplesPerHardwarePacket = 1024;
-
-  // The maximum number of samples in a hardware packet.
-  // This value is selected so that we can handle up to 192khz sample rate.
-  static const size_t kMaxSamplesPerHardwarePacket = 64 * 1024;
-
-  // This constant governs the hardware audio buffer size, this value should be
-  // chosen carefully.
-  // This value is selected so that we have 8192 samples for 48khz streams.
-  static const size_t kMillisecondsPerHardwarePacket = 170;
-
-  // Select the number of samples that can provide at least
-  // |kMillisecondsPerHardwarePacket| worth of audio data.
-  size_t samples = kMinSamplesPerHardwarePacket;
-  while (samples <= kMaxSamplesPerHardwarePacket &&
-         samples * base::Time::kMillisecondsPerSecond <
-         sample_rate * kMillisecondsPerHardwarePacket) {
-    samples *= 2;
-  }
-  return samples;
-}
-
 ChannelLayout GetInputChannelLayout() {
   DCHECK(RenderThreadImpl::current() != NULL);
 

content/renderer/media/audio_hardware.h

@@ -28,10 +28,6 @@ CONTENT_EXPORT int GetInputSampleRate();
 // Must be used in conjunction with AUDIO_PCM_LOW_LATENCY.
 CONTENT_EXPORT size_t GetOutputBufferSize();
 
-// Computes a buffer size based on the given |sample_rate|. Must be used in
-// conjunction with AUDIO_PCM_LINEAR.
-CONTENT_EXPORT size_t GetHighLatencyOutputBufferSize(int sample_rate);
-
 // Fetch the audio channel layout for the default input device.
 // Must be called from RenderThreadImpl::current().
 CONTENT_EXPORT ChannelLayout GetInputChannelLayout();

content/renderer/media/audio_input_device.h

@@ -95,8 +95,8 @@ class CONTENT_EXPORT AudioInputDevice
   class CONTENT_EXPORT CaptureCallback {
    public:
     virtual void Capture(const std::vector<float*>& audio_data,
-                         size_t number_of_frames,
-                         size_t audio_delay_milliseconds,
+                         int number_of_frames,
+                         int audio_delay_milliseconds,
                          double volume) = 0;
     virtual void OnCaptureError() = 0;
    protected:
@@ -148,7 +148,7 @@ class CONTENT_EXPORT AudioInputDevice
     return audio_parameters_.sample_rate();
   }
 
-  size_t buffer_size() const {
+  int buffer_size() const {
     return audio_parameters_.frames_per_buffer();
   }