Support for parsing encrypted WebM streams by src.

media/filters/ffmpeg_demuxer.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.
 
 // 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.
 //
 // FFmpegDemuxer sets the duration of pipeline during initialization by using
 // the duration of the longest audio/video stream.
 //
 // NOTE: since FFmpegDemuxer reads packets sequentially without seeking, media
 // files with very large drift between audio/video streams may result in
 // excessive memory consumption.
 //
 // When stopped, FFmpegDemuxer and FFmpegDemuxerStream release all callbacks
 // and buffered packets.  Reads from a stopped FFmpegDemuxerStream will not be
 // replied to.
 
 #ifndef MEDIA_FILTERS_FFMPEG_DEMUXER_H_
 #define MEDIA_FILTERS_FFMPEG_DEMUXER_H_
 
 #include <deque>
+#include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/demuxer.h"
 #include "media/base/pipeline.h"
 #include "media/base/video_decoder_config.h"
 #include "media/filters/ffmpeg_glue.h"
 
 // FFmpeg forward declarations.
 struct AVFormatContext;
 struct AVPacket;
 struct AVRational;
 struct AVStream;
 
 namespace media {
 
+// A new potentially encrypted stream has been parsed.
+// First parameter - The initialization data associated with the stream.
+// Second parameter - Number of bytes of the initialization data.
+typedef base::Callback<void(scoped_array<uint8>, int)> FFmpegNeedKeyCB;

[xhwang, 2012/08/29 05:08:14]

Move this typedef into FFmpegDemuxer and rename it to just NeedKeyCB?

[ddorwin, 2012/09/01 16:46:41]

We're going to eliminate this and replace it with a common Demuxer class, right?
Add a TODO to do that and remove this?

[fgalligan1, 2013/03/09 01:10:59]

What should I do with this at this point?

+
 class FFmpegDemuxer;
 class FFmpegH264ToAnnexBBitstreamConverter;
 class ScopedPtrAVFreePacket;
 
 class FFmpegDemuxerStream : public DemuxerStream {
  public:
   // Keeps a copy of |demuxer| and initializes itself using information
   // inside |stream|.  Both parameters must outlive |this|.
   FFmpegDemuxerStream(FFmpegDemuxer* demuxer, AVStream* stream);
 
@@ skipping 65 matching lines @@
   Ranges<base::TimeDelta> buffered_ranges_;
 
   typedef std::deque<scoped_refptr<DecoderBuffer> > BufferQueue;
   BufferQueue buffer_queue_;
 
   typedef std::deque<ReadCB> ReadQueue;
   ReadQueue read_queue_;
 
   scoped_ptr<FFmpegH264ToAnnexBBitstreamConverter> bitstream_converter_;
 
+  std::string current_key_id_;
+
   // Used to synchronize access to |buffer_queue_|, |read_queue_|, and
   // |stopped_|. This is so other threads can get access to buffers that have
   // already been demuxed without having the demuxer thread sending the
   // buffers. |lock_| must be acquired before any access to |buffer_queue_|,
   // |read_queue_|, or |stopped_|.
   mutable base::Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxerStream);
 };
 
 class MEDIA_EXPORT FFmpegDemuxer : public Demuxer, public FFmpegURLProtocol {
  public:
   FFmpegDemuxer(const scoped_refptr<base::MessageLoopProxy>& message_loop,
-                const scoped_refptr<DataSource>& data_source);
+                const scoped_refptr<DataSource>& data_source,
+                const FFmpegNeedKeyCB& need_key_cb);
 
   // Posts a task to perform additional demuxing.
   virtual void PostDemuxTask();
 
   // Demuxer implementation.
   virtual void Initialize(DemuxerHost* host,
                           const PipelineStatusCB& status_cb) OVERRIDE;
   virtual void Stop(const base::Closure& callback) OVERRIDE;
   virtual void Seek(base::TimeDelta time, const PipelineStatusCB& cb) OVERRIDE;
   virtual void OnAudioRendererDisabled() OVERRIDE;
   virtual void SetPlaybackRate(float playback_rate) OVERRIDE;
   virtual scoped_refptr<DemuxerStream> GetStream(
       DemuxerStream::Type type) OVERRIDE;
   virtual base::TimeDelta GetStartTime() const OVERRIDE;
 
   // FFmpegURLProtocol implementation.
   virtual size_t Read(size_t size, uint8* data) OVERRIDE;
   virtual bool GetPosition(int64* position_out) OVERRIDE;
   virtual bool SetPosition(int64 position) OVERRIDE;
   virtual bool GetSize(int64* size_out) OVERRIDE;
   virtual bool IsStreaming() OVERRIDE;
 
   // Provide access to FFmpegDemuxerStream.
   scoped_refptr<base::MessageLoopProxy> message_loop();
 
+  void NeedKey(const std::string& key_id);
+
   // Allow FFmpegDemuxerStream to notify us when there is updated information
   // about what buffered data is available.
   void NotifyBufferingChanged();
 
  private:
   // To allow tests access to privates.
   friend class FFmpegDemuxerTest;
 
   virtual ~FFmpegDemuxer();
 
@@ skipping 80 matching lines @@
   base::TimeDelta start_time_;
 
   // Whether audio has been disabled for this demuxer (in which case this class
   // drops packets destined for AUDIO demuxer streams on the floor).
   bool audio_disabled_;
 
   // Set if we know duration of the audio stream. Used when processing end of
   // stream -- at this moment we definitely know duration.
   bool duration_known_;
 
+  const FFmpegNeedKeyCB need_key_cb_;
+
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_