// Copyright (c) 2011 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. // // AudioRendererHost serves audio related requests from AudioRenderer which // lives inside the render process and provide access to audio hardware. // // This class is owned by BrowserRenderProcessHost, and instantiated on UI // thread, but all other operations and method calls happen on IO thread, so we // need to be extra careful about the lifetime of this object. AudioManager is a // singleton and created in IO thread, audio output streams are also created in // the IO thread, so we need to destroy them also in IO thread. After this class // is created, a task of OnInitialized() is posted on IO thread in which // singleton of AudioManager is created and. // // Here's an example of a typical IPC dialog for audio: // // Renderer AudioRendererHost // | | // | CreateStream > | // | < Created | // | | // | Play > | // | < Playing | time // | | // | < RequestAudioPacket | // | AudioPacketReady > | // | ... | // | < RequestAudioPacket | // | AudioPacketReady > | // | | // | ... | // | < RequestAudioPacket | // | AudioPacketReady > | // | ... | // | Pause > | // | < Paused | // | ... | // | Start > | // | < Started | // | ... | // | Close > | // v v // The above mode of operation uses relatively big buffers and has latencies // of 50 ms or more. There is a second mode of operation which is low latency. // For low latency audio, the picture above is modified by not having the // RequestAudioPacket and the AudioPacketReady messages, instead a SyncSocket // pair is used to signal buffer readiness without having to route messages // using the IO thread. #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_RENDERER_HOST_H_ #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_RENDERER_HOST_H_ #pragma once #include #include "base/gtest_prod_util.h" #include "base/memory/ref_counted.h" #include "base/memory/scoped_ptr.h" #include "base/process.h" #include "base/shared_memory.h" #include "content/browser/browser_message_filter.h" #include "content/common/content_export.h" #include "content/public/browser/browser_thread.h" #include "media/audio/audio_io.h" #include "media/audio/audio_output_controller.h" #include "media/audio/simple_sources.h" class AudioManager; struct AudioParameters; class MediaObserver; namespace content { class ResourceContext; } // namespace content class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter, public media::AudioOutputController::EventHandler { public: struct AudioEntry { AudioEntry(); ~AudioEntry(); // The AudioOutputController that manages the audio stream. scoped_refptr controller; // The audio stream ID. int stream_id; // Shared memory for transmission of the audio data. base::SharedMemory shared_memory; // The synchronous reader to be used by the controller. We have the // ownership of the reader. scoped_ptr reader; bool pending_buffer_request; // Set to true after we called Close() for the controller. bool pending_close; }; typedef std::map AudioEntryMap; // Called from UI thread from the owner of this object. AudioRendererHost(const content::ResourceContext* resource_context); // BrowserMessageFilter implementation. virtual void OnChannelClosing() OVERRIDE; virtual void OnDestruct() const OVERRIDE; virtual bool OnMessageReceived(const IPC::Message& message, bool* message_was_ok) OVERRIDE; // AudioOutputController::EventHandler implementations. virtual void OnCreated(media::AudioOutputController* controller) OVERRIDE; virtual void OnPlaying(media::AudioOutputController* controller) OVERRIDE; virtual void OnPaused(media::AudioOutputController* controller) OVERRIDE; virtual void OnError(media::AudioOutputController* controller, int error_code) OVERRIDE; virtual void OnMoreData(media::AudioOutputController* controller, AudioBuffersState buffers_state) OVERRIDE; private: friend class AudioRendererHostTest; friend class content::BrowserThread; friend class DeleteTask; friend class MockAudioRendererHost; FRIEND_TEST_ALL_PREFIXES(AudioRendererHostTest, CreateMockStream); FRIEND_TEST_ALL_PREFIXES(AudioRendererHostTest, MockStreamDataConversation); virtual ~AudioRendererHost(); // Methods called on IO thread ---------------------------------------------- // Audio related IPC message handlers. // Creates an audio output stream with the specified format. If this call is // successful this object would keep an internal entry of the stream for the // required properties. void OnCreateStream(int stream_id, const AudioParameters& params, bool low_latency); // Play the audio stream referenced by |stream_id|. void OnPlayStream(int stream_id); // Pause the audio stream referenced by |stream_id|. void OnPauseStream(int stream_id); // Discard all audio data in stream referenced by |stream_id|. void OnFlushStream(int stream_id); // Close the audio stream referenced by |stream_id|. void OnCloseStream(int stream_id); // Set the volume of the audio stream referenced by |stream_id|. void OnSetVolume(int stream_id, double volume); // Get the volume of the audio stream referenced by |stream_id|. void OnGetVolume(int stream_id); // Notify packet has been prepared for the audio stream. void OnNotifyPacketReady(int stream_id, uint32 packet_size); // Complete the process of creating an audio stream. This will set up the // shared memory or shared socket in low latency mode. void DoCompleteCreation(media::AudioOutputController* controller); // Send a state change message to the renderer. void DoSendPlayingMessage(media::AudioOutputController* controller); void DoSendPausedMessage(media::AudioOutputController* controller); // Request more data from the renderer. This method is used only in normal // latency mode. void DoRequestMoreData(media::AudioOutputController* controller, AudioBuffersState buffers_state); // Handle error coming from audio stream. void DoHandleError(media::AudioOutputController* controller, int error_code); // Send an error message to the renderer. void SendErrorMessage(int stream_id); // Delete all audio entry and all audio streams void DeleteEntries(); // Closes the stream. The stream is then deleted in DeleteEntry() after it // is closed. void CloseAndDeleteStream(AudioEntry* entry); // Called on the audio thread after the audio stream is closed. void OnStreamClosed(AudioEntry* entry); // Delete an audio entry and close the related audio stream. void DeleteEntry(AudioEntry* entry); // Delete audio entry and close the related audio stream due to an error, // and error message is send to the renderer. void DeleteEntryOnError(AudioEntry* entry); // A helper method to look up a AudioEntry identified by |stream_id|. // Returns NULL if not found. AudioEntry* LookupById(int stream_id); // Search for a AudioEntry having the reference to |controller|. // This method is used to look up an AudioEntry after a controller // event is received. AudioEntry* LookupByController(media::AudioOutputController* controller); // Return resource_context_->media_observer() or a cached copy thereof. // This is necessary because resource_context_ can be destructed before all // AudioEntries have been deleted. The MediaObserver's lifetime is tied to // that of the IO thread, so this is safe. MediaObserver* media_observer(); // A map of stream IDs to audio sources. AudioEntryMap audio_entries_; const content::ResourceContext* resource_context_; MediaObserver* media_observer_; DISALLOW_COPY_AND_ASSIGN(AudioRendererHost); }; #endif // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_RENDERER_HOST_H_