Refactor FFmpegVideoDecoder to try and generalize code common to all video decoders.

media/filters/ffmpeg_demuxer.h

 // Copyright (c) 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.
 
 // Implements the Demuxer interface using FFmpeg's libavformat.  At this time
 // will support demuxing any audio/video format thrown at it.  The streams
 // output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
 // key FFmpegCodecID which contains the CodecID enumeration value.  The CodecIDs
 // can be used to create and initialize the corresponding FFmpeg decoder.
 //
@@ skipping 21 matching lines @@
 #include "media/base/media_format.h"
 #include "media/filters/ffmpeg_glue.h"
 #include "media/filters/ffmpeg_interfaces.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 // FFmpeg forward declarations.
 struct AVCodecContext;
 struct AVBitStreamFilterContext;
 struct AVFormatContext;
 struct AVPacket;
+struct AVRational;
 struct AVStream;
 
 namespace media {
 
 class FFmpegDemuxer;
 
 // Forward declaration for scoped_ptr_malloc.
 class ScopedPtrAVFree;
 
 class FFmpegDemuxerStream : public DemuxerStream, public AVStreamProvider {
@@ skipping 34 matching lines @@
   virtual ~FFmpegDemuxerStream();
 
   // Carries out enqueuing a pending read on the demuxer thread.
   void ReadTask(Callback1<Buffer*>::Type* read_callback);
 
   // Attempts to fulfill a single pending read by dequeueing a buffer and read
   // callback pair and executing the callback.
   void FulfillPendingRead();
 
   // Converts an FFmpeg stream timestamp into a base::TimeDelta.
-  base::TimeDelta ConvertTimestamp(int64 timestamp);
+  static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
+                                                int64 timestamp);
 
   FFmpegDemuxer* demuxer_;
   AVStream* stream_;
   MediaFormat media_format_;
   base::TimeDelta duration_;
   bool discontinuous_;
   bool stopped_;
 
   typedef std::deque<scoped_refptr<Buffer> > BufferQueue;
   BufferQueue buffer_queue_;
@@ skipping 119 matching lines @@
   // If true, then it's our first seek and we won't call av_read_frame().  It's
   // a hack to get around some issue with FFmpeg.
   bool first_seek_hack_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_