content/browser/renderer_host/media/audio_sync_reader.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
   7
   8 #include "base/file_descriptor_posix.h"
   9 #include "base/process/process.h"
  10 #include "base/sync_socket.h"
  11 #include "base/synchronization/lock.h"
  12 #include "base/time/time.h"
  13 #include "media/audio/audio_output_controller.h"
  14 #include "media/base/audio_bus.h"
  15
  16 namespace base {
  17 class SharedMemory;
  18 }
  19
  20 namespace content {
  21
  22 // A AudioOutputController::SyncReader implementation using SyncSocket. This
  23 // is used by AudioOutputController to provide a low latency data source for
  24 // transmitting audio packets between the browser process and the renderer
  25 // process.
  26 class AudioSyncReader : public media::AudioOutputController::SyncReader {
  27  public:
  28   AudioSyncReader(base::SharedMemory* shared_memory,
  29                   const media::AudioParameters& params,
  30                   int input_channels);
  31
  32   virtual ~AudioSyncReader();
  33
  34   // media::AudioOutputController::SyncReader implementations.
  35   virtual void UpdatePendingBytes(uint32 bytes) OVERRIDE;
  36   virtual void Read(const media::AudioBus* source,
  37                     media::AudioBus* dest) OVERRIDE;
  38   virtual void Close() OVERRIDE;
  39
  40   bool Init();
  41   bool PrepareForeignSocketHandle(base::ProcessHandle process_handle,
  42 #if defined(OS_WIN)
  43                                   base::SyncSocket::Handle* foreign_handle);
  44 #else
  45                                   base::FileDescriptor* foreign_handle);
  46 #endif
  47
  48  private:
  49   // Blocks until data is ready for reading or a timeout expires.  Returns false
  50   // if an error or timeout occurs.
  51   bool WaitUntilDataIsReady();
  52
  53   const base::SharedMemory* const shared_memory_;
  54
  55   // Number of input channels for synchronized I/O.
  56   const int input_channels_;
  57
  58   // Mutes all incoming samples. This is used to prevent audible sound
  59   // during automated testing.
  60   const bool mute_audio_;
  61
  62   // Socket for transmitting audio data.
  63   scoped_ptr<base::CancelableSyncSocket> socket_;
  64
  65   // Socket to be used by the renderer. The reference is released after
  66   // PrepareForeignSocketHandle() is called and ran successfully.
  67   scoped_ptr<base::CancelableSyncSocket> foreign_socket_;
  68
  69   // Shared memory wrapper used for transferring audio data to Read() callers.
  70   scoped_ptr<media::AudioBus> output_bus_;
  71
  72   // Shared memory wrapper used for transferring audio data from Read() callers.
  73   scoped_ptr<media::AudioBus> input_bus_;
  74
  75   // Maximum amount of audio data which can be transferred in one Read() call.
  76   const int packet_size_;
  77
  78   // Track the number of times the renderer missed its real-time deadline and
  79   // report a UMA stat during destruction.
  80   size_t renderer_callback_count_;
  81   size_t renderer_missed_callback_count_;
  82
  83   // The maximum amount of time to wait for data from the renderer.  Calculated
  84   // from the parameters given at construction.
  85   const base::TimeDelta maximum_wait_time_;
  86
  87   // The index of the audio buffer we're expecting to be sent from the renderer;
  88   // used to block with timeout for audio data.
  89   uint32 buffer_index_;
  90
  91   DISALLOW_COPY_AND_ASSIGN(AudioSyncReader);
  92 };
  93
  94 }  // namespace content
  95
  96 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_