Add gapless playback support for AAC playback.

media/filters/source_buffer_stream.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.
 
 // SourceBufferStream is a data structure that stores media Buffers in ranges.
 // Buffers can be appended out of presentation order. Buffers are retrieved by
 // seeking to the desired start point and calling GetNextBuffer(). Buffers are
 // returned in sequential presentation order.
 
 #ifndef MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
@@ skipping 284 matching lines @@
   // timestamps that match |start| will be removed.
   // |*deleted_buffers| - Filled with buffers for the current playback position
   // if the removal range included the current playback position. These buffers
   // can be used as candidates for placing in the |track_buffer_|.
   void RemoveInternal(
       base::TimeDelta start, base::TimeDelta end, bool is_exclusive,
       BufferQueue* deleted_buffers);
 
   Type GetType() const;
 
+  // See GetNextBuffer() for additional details.  This method handles splice
+  // frame processing.
+  Status HandleNextBufferWithSplice(
+      scoped_refptr<StreamParserBuffer>* out_buffer);
+
+  // See GetNextBuffer() for additional details.  This method handles preroll
+  // frame processing.
+  Status HandleNextBufferWithPreroll(
+      scoped_refptr<StreamParserBuffer>* out_buffer);
+
   // See GetNextBuffer() for additional details.  The internal method hands out
-  // buffers from the |track_buffer_| and |selected_range_| without additional
-  // processing for splice frame buffers; which is handled by GetNextBuffer().
+  // single buffers from the |track_buffer_| and |selected_range_| without
+  // additional processing for splice frame or preroll buffers.
   Status GetNextBufferInternal(scoped_refptr<StreamParserBuffer>* out_buffer);
 
   // Called by PrepareRangesForNextAppend() before pruning overlapped buffers to
   // generate a splice frame with a small portion of the overlapped buffers.  If
   // a splice frame is generated, the first buffer in |new_buffers| will have
   // its timestamps, duration, and fade out preroll updated.
   void GenerateSpliceFrame(const BufferQueue& new_buffers);
 
+  // If |out_buffer| has splice buffers or preroll, sets |pending_buffer_|
+  // appropriately and returns true.  Otherwise returns false.
+  bool SetPendingBuffer(scoped_refptr<StreamParserBuffer>* out_buffer);
+
   // Callback used to report error strings that can help the web developer
   // figure out what is wrong with the content.
   LogCB log_cb_;
 
   // List of disjoint buffered ranges, ordered by start time.
   RangeList ranges_;
 
   // Indicates which decoder config is being used by the decoder.
   // GetNextBuffer() is only allows to return buffers that have a
   // config ID that matches this index. If there is a mismatch then
@@ skipping 56 matching lines @@
 
   // The maximum amount of data in bytes the stream will keep in memory.
   int memory_limit_;
 
   // Indicates that a kConfigChanged status has been reported by GetNextBuffer()
   // and GetCurrentXXXDecoderConfig() must be called to update the current
   // config. GetNextBuffer() must not be called again until
   // GetCurrentXXXDecoderConfig() has been called.
   bool config_change_pending_;
 
-  // Used by GetNextBuffer() when a buffer with fade out is returned from
-  // GetNextBufferInternal().  Will be set to the returned buffer and will be
-  // destroyed after the splice_buffers() section has been exhausted.
-  scoped_refptr<StreamParserBuffer> splice_buffer_;
+  // Used by HandleNextBufferWithSplice() or HandleNextBufferWithPreroll() when
+  // a splice frame buffer or buffer with preroll is returned from
+  // GetNextBufferInternal().
+  scoped_refptr<StreamParserBuffer> pending_buffer_;
 
   // Indicates which of the splice buffers in |splice_buffer_| should be
   // handled out next.
   size_t splice_buffers_index_;
 
-  // Indicates that all pre splice buffers have been handed out.
-  bool pre_splice_complete_;
+  // Indicates that all buffers before |pending_buffer_| have been handed out.
+  bool pending_buffers_complete_;
 
   // Indicates that splice frame generation is enabled.
   const bool splice_frames_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(SourceBufferStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_