SetVolume and GetVolume take one volume instead of separate left and right vo...

media/audio/audio_output.h

 // Copyright (c) 2008-2009 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_H_
 
 #include "base/basictypes.h"
 
 // Low-level audio output support. To make sound there are 3 objects involved:
@@ skipping 73 matching lines @@
   // Since implementor of AudioOutputStream may have internal buffers, right
   // after calling this method initial buffers are fetched.
   //
   // The output stream does not take ownership of this callback.
   virtual void Start(AudioSourceCallback* callback) = 0;
 
   // Stops playing audio. Effect might not be instantaneous as the hardware
   // might have locked audio data that is processing.
   virtual void Stop() = 0;
 
-  // Sets the relative volume, with range [0.0, 1.0] inclusive. For mono audio
-  // sources the volume must be the same in both channels.
-  virtual void SetVolume(double left_level, double right_level) = 0;
+  // Sets the relative volume, with range [0.0, 1.0] inclusive.
+  virtual void SetVolume(double volume) = 0;
 
-  // Gets the relative volume, with range [0.0, 1.0] inclusive. For mono audio
-  // sources the level is returned in both channels.
-  virtual void GetVolume(double* left_level, double* right_level) = 0;
+  // Gets the relative volume, with range [0.0, 1.0] inclusive.
+  virtual void GetVolume(double* volume) = 0;
 
   // Close the stream. This also generates AudioSourceCallback::OnClose().
   // After calling this method, the object should not be used anymore.
   virtual void Close() = 0;
 
  protected:
   virtual ~AudioOutputStream() {}
 };
 
 // Manages all audio resources. In particular it owns the AudioOutputStream
 // objects. Provides some convenience functions that avoid the need to provide
 // iterators over the existing streams.
 class AudioManager {
  public:
   enum Format {
-    AUDIO_PCM_LINEAR = 0, // Pulse code modulation means 'raw' amplitude
-                          // samples.
-    AUDIO_PCM_DELTA,      // Delta-encoded pulse code modulation.
-    AUDIO_MOCK,           // Creates a dummy AudioOutputStream object.
-    AUDIO_LAST_FORMAT     // Only used for validation of format.
+    AUDIO_PCM_LINEAR = 0,  // Pulse code modulation means 'raw' amplitude
+                           // samples.
+    AUDIO_PCM_DELTA,       // Delta-encoded pulse code modulation.
+    AUDIO_MOCK,            // Creates a dummy AudioOutputStream object.
+    AUDIO_LAST_FORMAT      // Only used for validation of format.
   };
 
   // Telephone quality sample rate, mostly for speech-only audio.
   static const int kTelephoneSampleRate = 8000;
   // CD sampling rate is 44.1 KHz or conveniently 2x2x3x3x5x5x7x7.
   static const int kAudioCDSampleRate = 44100;
   // Digital Audio Tape sample rate.
   static const int kAudioDATSampleRate = 48000;
 
   // Returns true if the OS reports existence of audio devices. This does not
@@ skipping 20 matching lines @@
   // Get AudioManager singleton.
   // TODO(cpu): Define threading requirements for interacting with AudioManager.
   static AudioManager* GetAudioManager();
 
  protected:
   virtual ~AudioManager() {}
 };
 
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_H_