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
  33   virtual ~OpenSLESOutputStream();
  34
  35   // Implementation of AudioOutputStream.
  36   virtual bool Open() OVERRIDE;
  37   virtual void Close() OVERRIDE;
  38   virtual void Start(AudioSourceCallback* callback) OVERRIDE;
  39   virtual void Stop() OVERRIDE;
  40   virtual void SetVolume(double volume) OVERRIDE;
  41   virtual void GetVolume(double* volume) OVERRIDE;
  42
  43   // Set the value of |muted_|. It does not affect |volume_| which can be
  44   // got by calling GetVolume(). See comments for |muted_| below.
  45   void SetMute(bool muted);
  46
  47  private:
  48   bool CreatePlayer();
  49
  50   // Called from OpenSLES specific audio worker thread.
  51   static void SimpleBufferQueueCallback(
  52       SLAndroidSimpleBufferQueueItf buffer_queue,
  53       void* instance);
  54
  55   // Fills up one buffer by asking the registered source for data.
  56   // Called from OpenSLES specific audio worker thread.
  57   void FillBufferQueue();
  58
  59   // Called from the audio manager thread.
  60   void FillBufferQueueNoLock();
  61
  62   // Called in Open();
  63   void SetupAudioBuffer();
  64
  65   // Called in Close();
  66   void ReleaseAudioBuffer();
  67
  68   // If OpenSLES reports an error this function handles it and passes it to
  69   // the attached AudioOutputCallback::OnError().
  70   void HandleError(SLresult error);
  71
  72   base::ThreadChecker thread_checker_;
  73
  74   // Protects |callback_|, |active_buffer_index_|, |audio_data_|,
  75   // |buffer_size_bytes_| and |simple_buffer_queue_|.
  76   base::Lock lock_;
  77
  78   AudioManagerAndroid* audio_manager_;
  79
  80   AudioSourceCallback* callback_;
  81
  82   // Shared engine interfaces for the app.
  83   media::ScopedSLObjectItf engine_object_;
  84   media::ScopedSLObjectItf player_object_;
  85   media::ScopedSLObjectItf output_mixer_;
  86
  87   SLPlayItf player_;
  88
  89   // Buffer queue recorder interface.
  90   SLAndroidSimpleBufferQueueItf simple_buffer_queue_;
  91
  92   SLDataFormat_PCM format_;
  93
  94   // Audio buffers that are allocated in the constructor based on
  95   // info from audio parameters.
  96   uint8* audio_data_[kMaxNumOfBuffersInQueue];
  97
  98   int active_buffer_index_;
  99   size_t buffer_size_bytes_;
 100
 101   bool started_;
 102
 103   // Volume control coming from hardware. It overrides |volume_| when it's
 104   // true. Otherwise, use |volume_| for scaling.
 105   // This is needed because platform voice volume never goes to zero in
 106   // COMMUNICATION mode on Android.
 107   bool muted_;
 108
 109   // Volume level from 0 to 1.
 110   float volume_;
 111
 112   // Container for retrieving data from AudioSourceCallback::OnMoreData().
 113   scoped_ptr<AudioBus> audio_bus_;
 114
 115   DISALLOW_COPY_AND_ASSIGN(OpenSLESOutputStream);
 116 };
 117
 118 }  // namespace media
 119
 120 #endif  // MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_