Enhance AudioSplicer to crossfade marked splice frames.

media/base/audio_splicer.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_AUDIO_SPLICER_H_
 #define MEDIA_BASE_AUDIO_SPLICER_H_
 
 #include <deque>
 
 #include "base/memory/ref_counted.h"
@@ skipping 11 matching lines @@
   AudioSplicer(int samples_per_second);
   ~AudioSplicer();
 
   // Resets the splicer state by clearing the output buffers queue,
   // and resetting the timestamp helper.
   void Reset();
 
   // Adds a new buffer full of samples or end of stream buffer to the splicer.
   // Returns true if the buffer was accepted. False is returned if an error
   // occurred.
-  bool AddInput(const scoped_refptr<AudioBuffer>& input);
+  bool AddInput(const scoped_refptr<DecoderBuffer>& origin_buffer,
+                const scoped_refptr<AudioBuffer>& input);
 
   // Returns true if the splicer has a buffer to return.
   bool HasNextBuffer() const;
 
   // Removes the next buffer from the output buffer queue and returns it.
   // This should only be called if HasNextBuffer() returns true.
   scoped_refptr<AudioBuffer> GetNextBuffer();
 
  private:
   void AddOutputBuffer(const scoped_refptr<AudioBuffer>& buffer);
 
   AudioTimestampHelper output_timestamp_helper_;
-
-  // Minimum gap size needed before the splicer will take action to
-  // fill a gap. This avoids periodically inserting and then dropping samples
-  // when the buffer timestamps are slightly off because of timestamp rounding
-  // in the source content. Unit is frames.
-  int min_gap_size_;
-
   std::deque<scoped_refptr<AudioBuffer> > output_buffers_;
   bool received_end_of_stream_;
 
+  // Inner splicer for handling splice frames.  Responsible for trimming and
+  // crossfading frames before exposing them for consumption by GetNextBuffer().
+  //
+  // Required since input buffers may require trimming arbitrarily large amounts
+  // of samples prior to crossfading.  Adding those samples as is to the "outer"
+  // AudioSplicer will result in incorrect timestamp generation.
+  AudioSplicer splice_frame_splicer_;

[acolwell GONE FROM CHROMIUM, 2014/02/10 20:19:57]

How does this compile? This is a recursive declaration.

[DaleCurtis, 2014/02/15 01:20:02]

As discussed offline, it doesn't, sorry should have been more clear that this
was a quick and dirty CL for design review purposes.

+
   DISALLOW_IMPLICIT_CONSTRUCTORS(AudioSplicer);
 };
 
 }  // namespace media
 
 #endif