Mix to an intermediate buffer.

services/media/audio/platform/generic/mixer.h

 // Copyright 2015 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 SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXER_H_
 #define SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXER_H_
 
 #include <memory>
 
 #include "mojo/services/media/common/interfaces/media_types.mojom.h"
@@ skipping 17 matching lines @@
   // Select
   //
   // Select an appropriate instance of a mixer based on the properties of the
   // source and destination formats.
   //
   // TODO(johngro): Come back here and add a way to indicate user preference
   // where appropriate.  For example, where we might chose a linear
   // interpolation sampler, the user may actually prefer cubic interpolation, or
   // perhaps just a point sampler.
   static MixerPtr Select(const LpcmMediaTypeDetailsPtr& src_format,
-                         const LpcmMediaTypeDetailsPtr& dst_format);
+                         const LpcmMediaTypeDetailsPtr* dst_format);
 
   // Mix
   //
   // Perform a mixing operation from the source buffer into the destination
   // buffer.
   //
   // @param dst
   // The pointer to the destination buffer into which frames will be mixed.
   //
   // @param dst_frames
@@ skipping 32 matching lines @@
   // output samples, then frac_step_size+1 for M samples, etc...
   //
   // @param accumulate
   // When true, the mixer will accumulate into the destination buffer (read,
   // sum, clip, write-back).  When false, the mixer will simply replace the
   // destination buffer with its output.
   //
   // @return True if the mixer is finished with this source data and will not
   // need it in the future.  False if the mixer has not consumed the entire
   // source buffer and will need more of it in the future.
-  virtual bool Mix(void*       dst,
+  virtual bool Mix(int32_t*    dst,
                    uint32_t    dst_frames,
                    uint32_t*   dst_offset,
                    const void* src,
                    uint32_t    frac_src_frames,
                    int32_t*    frac_src_offset,
                    uint32_t    frac_step_size,
                    bool        accumulate) = 0;
 
   // Reset
   //
@@ skipping 23 matching lines @@
  private:
   uint32_t pos_filter_width_;
   uint32_t neg_filter_width_;
 };
 
 }  // namespace audio
 }  // namespace media
 }  // namespace mojo
 
 #endif  // SERVICES_MEDIA_AUDIO_PLATFORM_GENERIC_MIXER_H_