FFmpeg video decoder glue code...

media/filters/ffmpeg_video_decoder.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.
 
 
 #ifndef MEDIA_FILTERS_FFMPEG_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_FFMPEG_VIDEO_DECODER_H_
 
+#include <queue>
+
 #include "media/base/factory.h"
 #include "media/filters/decoder_base.h"
 
+// FFmpeg types.
+struct AVCodecContext;
+struct AVFrame;
+
 namespace media {
 
 //------------------------------------------------------------------------------
 
 class FFmpegVideoDecoder : public DecoderBase<VideoDecoder, VideoFrame> {
  public:
   static FilterFactory* CreateFactory() {
     return new FilterFactoryImpl0<FFmpegVideoDecoder>();
   }
 
   static bool IsMediaFormatSupported(const MediaFormat& media_format);
 
   virtual bool OnInitialize(DemuxerStream* demuxer_stream);
 
-  virtual void OnDecode(Buffer* input);
+  virtual void OnDecode(Buffer* buffer);
 
  private:
   friend class FilterFactoryImpl0<FFmpegVideoDecoder>;
   FFmpegVideoDecoder();
   virtual ~FFmpegVideoDecoder();
 
+  bool EnqueueVideoFrame(VideoSurface::Format surface_format,
+                         const AVFrame& frame);
+
+  void CopyPlane(size_t plane, const VideoSurface& surface,
+                 const AVFrame& frame);
+
+  size_t width_;
+  size_t height_;
+
+  // FFmpeg outputs packets in decode timestamp (dts) order, which may not
+  // always be in presentation timestamp (pts) order.  Therefore, when Process
+  // is called we cannot assume that the pts of the input |buffer| passed to the
+  // OnDecode() method is necessarily the pts of video frame.  For example:
+  //
+  // Process()    Timestamp     Timestamp
+  //  Call #      Buffer In     Buffer Out
+  //    1             1             1
+  //    2             3            --- <--- frame 3 buffered by FFmpeg
+  //    3             2             2
+  //    4             4             3  <--- copying timestamp 4 and 6 would be
+  //    5             6             4  <-'  incorrect, which is why we sort and
+  //    6             5             5       queue incoming timestamps
+
+  // A queue entry that holds a timestamp and a duration.
+  struct TimeTuple {
+    base::TimeDelta timestamp;
+    base::TimeDelta duration;
+
+    bool operator<(const TimeTuple& other) const {
+      return timestamp >= other.timestamp;
+    }
+  };
+
+  // A priority queue of presentation TimeTuples.
+  typedef std::priority_queue<TimeTuple> TimeQueue;
+  TimeQueue time_queue_;
+
+  AVCodecContext* codec_context_;
+
   DISALLOW_COPY_AND_ASSIGN(FFmpegVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_VIDEO_DECODER_H_