media/audio/android/opensles_output.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 MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_
   6 #define MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_
   7
   8 #include <SLES/OpenSLES.h>
   9 #include <SLES/OpenSLES_Android.h>
  10
  11 #include "base/compiler_specific.h"
  12 #include "base/synchronization/lock.h"
  13 #include "base/threading/thread_checker.h"
  14 #include "media/audio/android/opensles_util.h"
  15 #include "media/audio/audio_io.h"
  16 #include "media/audio/audio_parameters.h"
  17
  18 namespace media {
  19
  20 class AudioManagerAndroid;
  21
  22 // Implements PCM audio output support for Android using the OpenSLES API.
  23 // This class is created and lives on the Audio Manager thread but recorded
  24 // audio buffers are given to us from an internal OpenSLES audio thread.
  25 // All public methods should be called on the Audio Manager thread.
  26 class OpenSLESOutputStream : public AudioOutputStream {
  27  public:
  28   static const int kMaxNumOfBuffersInQueue = 2;
  29
  30   OpenSLESOutputStream(AudioManagerAndroid* manager,
  31                        const AudioParameters& params,
  32                        SLint32 stream_type);
  33
  34   virtual ~OpenSLESOutputStream();
  35
  36   // Implementation of AudioOutputStream.
  37   virtual bool Open() OVERRIDE;
  38   virtual void Close() OVERRIDE;
  39   virtual void Start(AudioSourceCallback* callback) OVERRIDE;
  40   virtual void Stop() OVERRIDE;
  41   virtual void SetVolume(double volume) OVERRIDE;
  42   virtual void GetVolume(double* volume) OVERRIDE;
  43
  44   // Set the value of |muted_|. It does not affect |volume_| which can be
  45   // got by calling GetVolume(). See comments for |muted_| below.
  46   void SetMute(bool muted);
  47
  48  private:
  49   bool CreatePlayer();
  50
  51   // Called from OpenSLES specific audio worker thread.
  52   static void SimpleBufferQueueCallback(
  53       SLAndroidSimpleBufferQueueItf buffer_queue,
  54       void* instance);
  55
  56   // Fills up one buffer by asking the registered source for data.
  57   // Called from OpenSLES specific audio worker thread.
  58   void FillBufferQueue();
  59
  60   // Called from the audio manager thread.
  61   void FillBufferQueueNoLock();
  62
  63   // Called in Open();
  64   void SetupAudioBuffer();
  65
  66   // Called in Close();
  67   void ReleaseAudioBuffer();
  68
  69   // If OpenSLES reports an error this function handles it and passes it to
  70   // the attached AudioOutputCallback::OnError().
  71   void HandleError(SLresult error);
  72
  73   base::ThreadChecker thread_checker_;
  74
  75   // Protects |callback_|, |active_buffer_index_|, |audio_data_|,
  76   // |buffer_size_bytes_| and |simple_buffer_queue_|.
  77   base::Lock lock_;
  78
  79   AudioManagerAndroid* audio_manager_;
  80
  81   // Audio playback stream type.
  82   // See SLES/OpenSLES_Android.h for details.
  83   SLint32 stream_type_;
  84
  85   AudioSourceCallback* callback_;
  86
  87   // Shared engine interfaces for the app.
  88   media::ScopedSLObjectItf engine_object_;
  89   media::ScopedSLObjectItf player_object_;
  90   media::ScopedSLObjectItf output_mixer_;
  91
  92   SLPlayItf player_;
  93
  94   // Buffer queue recorder interface.
  95   SLAndroidSimpleBufferQueueItf simple_buffer_queue_;
  96
  97   SLDataFormat_PCM format_;
  98
  99   // Audio buffers that are allocated in the constructor based on
 100   // info from audio parameters.
 101   uint8* audio_data_[kMaxNumOfBuffersInQueue];
 102
 103   int active_buffer_index_;
 104   size_t buffer_size_bytes_;
 105
 106   bool started_;
 107
 108   // Volume control coming from hardware. It overrides |volume_| when it's
 109   // true. Otherwise, use |volume_| for scaling.
 110   // This is needed because platform voice volume never goes to zero in
 111   // COMMUNICATION mode on Android.
 112   bool muted_;
 113
 114   // Volume level from 0 to 1.
 115   float volume_;
 116
 117   // Container for retrieving data from AudioSourceCallback::OnMoreData().
 118   scoped_ptr<AudioBus> audio_bus_;
 119
 120   DISALLOW_COPY_AND_ASSIGN(OpenSLESOutputStream);
 121 };
 122
 123 }  // namespace media
 124
 125 #endif  // MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_