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// Copyright (c) 2009 The Chromium Authors. All rights reserved. Use of this
// source code is governed by a BSD-style license that can be found in the
// LICENSE file.
//
// Audio rendering unit utilizing audio output stream provided by browser
// process through IPC.
//
// Relationship of classes.
//
// AudioRendererHost AudioRendererImpl
// ^ ^
// | |
// v IPC v
// ResourceMessageFilter <---------> RenderView
//
// Implementation of interface with audio device is in AudioRendererHost and
// it provides services and entry points in ResourceMessageFilter, allowing
// usage of IPC calls to interact with audio device. RenderView acts as a portal
// for IPC calls and does no more than delegation.
//
// Transportation of audio buffer is done by using shared memory, after
// OnCreateAudioStream is executed, OnCreated would be called along with a
// SharedMemoryHandle upon successful creation of audio output stream in the
// browser process. The same piece of shared memory would be used during the
// lifetime of this unit.
//
// This class lives inside three threads during it's lifetime, namely:
// 1. Render thread
// The thread within which this class is constructed and destroyed,
// interfacing with RenderView should only happen here.
// 2. Pipeline thread
// Initialization of filter and proper stopping of filters happens here.
// Properties of this filter is also set in this thread.
// 3. Audio decoder thread (If there's one.)
// Responsible for decoding audio data and gives raw PCM data to this object.
//
// Methods categorized according to the thread(s) they are running on.
//
// Render thread
// +-- CreateFactory()
// | Helper method for construction this class.
// |-- IsMetidFormatSupported()
// | Helper method to identify media formats accepted by this class for
// | construction.
// |-- OnCreateAudioStream()
// | Calls RenderView::CreateAudioStream().
// |-- OnStartAudioStream()
// | Calls RenderView::StartAudioStream().
// |-- OnCloseAudioStream()
// | Calls RenderView::CloseAudioStream().
// |-- OnSetAudioVolume()
// | Calls RenderView::SetAudioVolume().
// |-- OnNotifyAudioPacketReady
// | Calls RenderView::NotifyAudioPacketReady().
// |-- OnRequestPacket()
// | Called from RenderView when an audio packet requested is received
// | from browser process.
// |-- OnStateChanged()
// | Called from RenderView upon state change of the audio output stream
// | in the browser process. Error of the output stream is reported here.
// |-- OnCreated()
// | Called from RenderView upon successful creation of audio output stream
// | in the browser process, called along with a SharedMemoryHandle.
// |-- OnVolume()
// | Called from RenderView about the volume of the audio output stream.
// \-- ReleaseRendererResource()
// Release resources that live inside render thread.
//
// Pipeline thread
// +-- AudioRendererImpl()
// | Constructor method.
// |-- ~AudioRendererImpl()
// | Destructor method.
// |-- SetPlaybackRate()
// | Given the playback rate information.
// |-- GetMediaFormat()
// | Obtain the current media format of this unit.
// |-- SetVolume()
// | Given the volume information.
// |-- OnInitialize()
// | Called from AudioRendererBase for initialization event.
// \-- OnStop()
// Called from AudioRendererBase for stop event.
//
// Audio decoder thread (If there's one.)
// \-- OnAssignment()
// A raw PCM audio packet buffer is recevied here, this method is called
// from pipeline thread if audio decoder thread does not exist.
#ifndef CHROME_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_
#define CHROME_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_
#include "base/shared_memory.h"
#include "base/waitable_event.h"
#include "media/audio/audio_output.h"
#include "media/base/factory.h"
#include "media/base/filters.h"
#include "media/filters/audio_renderer_base.h"
class WebMediaPlayerDelegateImpl;
class AudioRendererImpl : public media::AudioRendererBase {
public:
// Methods called on render thread ------------------------------------------
// Methods called during construction.
static media::FilterFactory* CreateFactory(
WebMediaPlayerDelegateImpl* delegate) {
return new media::FilterFactoryImpl1<AudioRendererImpl,
WebMediaPlayerDelegateImpl*>(delegate);
}
static bool IsMediaFormatSupported(const media::MediaFormat& format);
// Methods call from RenderView when audio related IPC messages are received
// from browser process.
void OnRequestPacket();
void OnStateChanged(AudioOutputStream::State state, int info);
void OnCreated(base::SharedMemoryHandle handle, size_t length);
void OnVolume(double left, double right);
// Release resources that lives in renderer thread, i.e. audio output streams.
void ReleaseRendererResources();
// Methods called on pipeline thread ----------------------------------------
// media::MediaFilter implementation.
virtual void SetPlaybackRate(float rate);
// media::AudioRenderer implementation.
virtual void SetVolume(float volume);
// AssignableBuffer<AudioRendererBase, BufferInterface> implementation.
virtual void OnAssignment(media::Buffer* buffer_in);
protected:
// Methods called on audio renderer thread ----------------------------------
// These methods are called from AudioRendererBase.
virtual bool OnInitialize(const media::MediaFormat& media_format);
virtual void OnStop();
private:
friend class media::FilterFactoryImpl1<AudioRendererImpl,
WebMediaPlayerDelegateImpl*>;
explicit AudioRendererImpl(WebMediaPlayerDelegateImpl* delegate);
virtual ~AudioRendererImpl();
// Methods call on render thread --------------------------------------------
// The following methods are tasks posted on the render thread that needs to
// be executed on that thread. They interact with WebMediaPlayerDelegateImpl
// and the containing RenderView, because method calls to RenderView must be
// executed on render thread.
void OnCreateAudioStream(AudioManager::Format format, int channels,
int sample_rate, int bits_per_sample,
size_t packet_size);
void OnStartAudioStream();
void OnCloseAudioStream();
void OnSetAudioVolume(double left, double right);
void OnNotifyAudioPacketReady();
WebMediaPlayerDelegateImpl* delegate_;
// ID of the stream created in the browser process.
int32 stream_id_;
// Memory shared by the browser process for audio buffer.
scoped_ptr<base::SharedMemory> shared_memory_;
size_t shared_memory_size_;
// Flag that tells whether we have any unfulfilled packet request.
bool packet_requested_;
// Message loop for the render thread, it's the message loop where this class
// is constructed.
MessageLoop* render_loop_;
// Event for releasing resources that live in render thread.
base::WaitableEvent resource_release_event_;
DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
};
#endif // CHROME_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_
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