Render inband text tracks in the media pipeline

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.
 //
@@ skipping 16 matching lines @@
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_vector.h"
 #include "base/threading/thread.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/decoder_buffer_queue.h"
 #include "media/base/demuxer.h"
 #include "media/base/pipeline.h"
+#include "media/base/text_track_config.h"
 #include "media/base/video_decoder_config.h"
 #include "media/filters/blocking_url_protocol.h"
 
 // FFmpeg forward declarations.
 struct AVPacket;
 struct AVRational;
 struct AVStream;
 
 namespace media {
 
@@ skipping 39 matching lines @@
   // Returns the range of buffered data in this stream.
   Ranges<base::TimeDelta> GetBufferedRanges() const;
 
   // Returns elapsed time based on the already queued packets.
   // Used to determine stream duration when it's not known ahead of time.
   base::TimeDelta GetElapsedTime() const;
 
   // Returns true if this stream has capacity for additional data.
   bool HasAvailableCapacity();
 
+  TextKind GetTextKind() const;
+
+  // Returns the value associated with |key| in the metadata for the avstream.
+  // Returns an empty string if the key is not present.
+  std::string GetMetadata(const char* key) const;
+
  private:
   friend class FFmpegDemuxerTest;
 
   // Runs |read_cb_| if present with the front of |buffer_queue_|, calling
   // NotifyCapacityAvailable() if capacity is still available.
   void SatisfyPendingRead();
 
   // Converts an FFmpeg stream timestamp into a base::TimeDelta.
   static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
                                                 int64 timestamp);
@@ skipping 23 matching lines @@
 class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
  public:
   FFmpegDemuxer(const scoped_refptr<base::MessageLoopProxy>& message_loop,
                 DataSource* data_source,
                 const NeedKeyCB& need_key_cb,
                 const scoped_refptr<MediaLog>& media_log);
   virtual ~FFmpegDemuxer();
 
   // Demuxer implementation.
   virtual void Initialize(DemuxerHost* host,
-                          const PipelineStatusCB& status_cb) OVERRIDE;
+                          const PipelineStatusCB& status_cb,
+                          bool enable_text_tracks) OVERRIDE;
   virtual void Stop(const base::Closure& callback) OVERRIDE;
   virtual void Seek(base::TimeDelta time, const PipelineStatusCB& cb) OVERRIDE;
   virtual void OnAudioRendererDisabled() OVERRIDE;
   virtual DemuxerStream* GetStream(DemuxerStream::Type type) OVERRIDE;
   virtual base::TimeDelta GetStartTime() const OVERRIDE;
 
   // Calls |need_key_cb_| with the initialization data encountered in the file.
   void FireNeedKey(const std::string& init_data_type,
                    const std::string& encryption_key_id);
 
@@ skipping 27 matching lines @@
   // Signal all FFmpegDemuxerStreams that the stream has ended.
   void StreamHasEnded();
 
   // Called by |url_protocol_| whenever |data_source_| returns a read error.
   void OnDataSourceError();
 
   // Returns the stream from |streams_| that matches |type| as an
   // FFmpegDemuxerStream.
   FFmpegDemuxerStream* GetFFmpegStream(DemuxerStream::Type type) const;
 
+  // Called after the streams have been collected from the media, to allow
+  // the text renderer to bind each text stream to the cue rendering engine.
+  void AddTextStreams();
+
   DemuxerHost* host_;
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
   base::WeakPtrFactory<FFmpegDemuxer> weak_factory_;
   base::WeakPtr<FFmpegDemuxer> weak_this_;
 
   // Thread on which all blocking FFmpeg operations are executed.
   base::Thread blocking_thread_;
 
   // Tracks if there's an outstanding av_read_frame() operation.
@@ skipping 29 matching lines @@
 
   // The first timestamp of the opened media file. This is used to set the
   // starting clock value to match the timestamps in the media file. Default
   // is 0.
   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_;
 
+  // Whether text streams have been enabled for this demuxer.
+  bool text_enabled_;
+
   // 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_;
 
   // FFmpegURLProtocol implementation and corresponding glue bits.
   BlockingUrlProtocol url_protocol_;
   scoped_ptr<FFmpegGlue> glue_;
 
   const NeedKeyCB need_key_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_