Motown: Ffmpeg video decoder

services/media/framework_ffmpeg/ffmpeg_video_decoder.h

 // Copyright 2016 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_FRAMEWORK_FFMPEG_FFMPEG_VIDEO_DECODER_H_
 #define SERVICES_MEDIA_FRAMEWORK_FFMPEG_FFMPEG_VIDEO_DECODER_H_
 
 #include "services/media/framework_ffmpeg/ffmpeg_decoder_base.h"
 
 namespace mojo {
 namespace media {
 
 // Decoder implementation employing and ffmpeg video decoder.
 // TODO(dalesat): Complete this.
 class FfmpegVideoDecoder : public FfmpegDecoderBase {
  public:
   FfmpegVideoDecoder(AvCodecContextPtr av_codec_context);
 
   ~FfmpegVideoDecoder() override;
 
  protected:
   // FfmpegDecoderBase overrides.
+  void Flush() override;
+
   int Decode(const AVPacket& av_packet,
              const ffmpeg::AvFramePtr& av_frame_ptr,
              PayloadAllocator* allocator,
              bool* frame_decoded_out) override;
 
   PacketPtr CreateOutputPacket(const AVFrame& av_frame,
                                PayloadAllocator* allocator) override;
 
   PacketPtr CreateOutputEndOfStreamPacket() override;
 
  private:
+  using Extent = VideoStreamType::Extent;
+
   // Callback used by the ffmpeg decoder to acquire a buffer.
   static int AllocateBufferForAvFrame(AVCodecContext* av_codec_context,
                                       AVFrame* av_frame,
                                       int flags);
 
   // Callback used by the ffmpeg decoder to release a buffer.
   static void ReleaseBufferForAvFrame(void* opaque, uint8_t* buffer);
 
-  // AllocateBufferForAvFrame deposits the packet size here, because there's
-  // no good evidence of it after avcodec_decode_audio4 completes.
-  uint64_t packet_size_;
+  // The allocator used by avcodec_decode_audio4 to provide context for
+  // AllocateBufferForAvFrame. This is set only during the call to
+  // avcodec_decode_audio4.
+  PayloadAllocator* allocator_;

[kulakowski, 2016/04/27 02:16:30]

Are PayloadAllocators some global-ish things? Or otherwise, who owns them?

[dalesat, 2016/04/27 15:40:14]

PayloadAllocator implementations come in two forms: a component like
MojoProducer exposes PayloadAllocator so it can allocate out of a shared buffer,
and the vanilla allocator, which is singleton. I get that it's weird to use a
raw pointer these days. I'll probably change that, but as part of a general
overhaul of how allocators and packets are done. We're going to need things like
packets that refer to texture memory, etc.

 
-  // This is used to verify that an allocated buffer is being used as expected
-  // by ffmpeg avcodec_decode_audio4. AllocateBufferForAvFrame sets it.
-  // void* packet_buffer_;
+  // Used to supply PTS for end-of-stream.
+  int64_t next_pts_ = Packet::kUnknownPts;
+
+  // TODO(dalesat): For investigation purposes only...remove one day.

[kulakowski, 2016/04/27 02:16:30]

Does this mean all three of the following members?

[dalesat, 2016/04/27 15:40:14]

Yes. Changed the comment.

+  bool first_frame_ = true;
+  AVColorSpace colorspace_;
+  Extent coded_size_;
 };
 
 }  // namespace media
 }  // namespace mojo
 
 #endif  // SERVICES_MEDIA_FRAMEWORK_FFMPEG_FFMPEG_VIDEO_DECODER_H_