Pass more detailed audio hardware configuration information to the renderer

media/base/channel_mixer.h

 // Copyright (c) 2012 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_BASE_CHANNEL_MIXER_H_
 #define MEDIA_BASE_CHANNEL_MIXER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "media/base/channel_layout.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class AudioBus;
+class AudioParameters;
 
 // ChannelMixer is for converting audio between channel layouts.  The conversion
 // matrix is built upon construction and used during each Transform() call.  The
 // algorithm works by generating a conversion matrix mapping each output channel
 // to list of input channels.  The transform renders all of the output channels,
 // with each output channel rendered according to a weighted sum of the relevant
 // input channels as defined in the matrix.
 class MEDIA_EXPORT ChannelMixer {
  public:
-  ChannelMixer(ChannelLayout input, ChannelLayout output);
+  ChannelMixer(ChannelLayout input_layout, ChannelLayout output_layout);
+  ChannelMixer(const AudioParameters& input, const AudioParameters& output);
   ~ChannelMixer();
 
+  void Initialize(ChannelLayout input_layout, int input_channels,
+                  ChannelLayout output_layout, int output_channels);
+
   // Transforms all channels from |input| into |output| channels.
   void Transform(const AudioBus* input, AudioBus* output);
 
  private:
   // Constructor helper methods for managing unaccounted input channels.
   void AccountFor(Channels ch);
   bool IsUnaccounted(Channels ch);
 
   // Helper methods for checking if |ch| exists in either |input_layout_| or
   // |output_layout_| respectively.
@@ skipping 20 matching lines @@
   // Optimization case for when we can simply remap the input channels to output
   // channels and don't need to do a multiply-accumulate loop over |matrix_|.
   bool remapping_;
 
   DISALLOW_COPY_AND_ASSIGN(ChannelMixer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CHANNEL_MIXER_H_