media/filters/ffmpeg_demuxer.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Implements the Demuxer interface using FFmpeg's libavformat.  At this time
   6 // will support demuxing any audio/video format thrown at it.  The streams
   7 // output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
   8 // key FFmpegCodecID which contains the CodecID enumeration value.  The CodecIDs
   9 // can be used to create and initialize the corresponding FFmpeg decoder.
  10 //
  11 // FFmpegDemuxer sets the duration of pipeline during initialization by using
  12 // the duration of the longest audio/video stream.
  13 //
  14 // NOTE: since FFmpegDemuxer reads packets sequentially without seeking, media
  15 // files with very large drift between audio/video streams may result in
  16 // excessive memory consumption.
  17 //
  18 // When stopped, FFmpegDemuxer and FFmpegDemuxerStream release all callbacks
  19 // and buffered packets.  Reads from a stopped FFmpegDemuxerStream will not be
  20 // replied to.
  21
  22 #ifndef MEDIA_FILTERS_FFMPEG_DEMUXER_H_
  23 #define MEDIA_FILTERS_FFMPEG_DEMUXER_H_
  24
  25 #include <vector>
  26
  27 #include "base/callback.h"
  28 #include "base/gtest_prod_util.h"
  29 #include "base/threading/thread.h"
  30 #include "media/base/audio_decoder_config.h"
  31 #include "media/base/decoder_buffer.h"
  32 #include "media/base/decoder_buffer_queue.h"
  33 #include "media/base/demuxer.h"
  34 #include "media/base/pipeline.h"
  35 #include "media/base/video_decoder_config.h"
  36 #include "media/filters/blocking_url_protocol.h"
  37
  38 // FFmpeg forward declarations.
  39 struct AVPacket;
  40 struct AVRational;
  41 struct AVStream;
  42
  43 namespace media {
  44
  45 class FFmpegDemuxer;
  46 class FFmpegGlue;
  47 class FFmpegH264ToAnnexBBitstreamConverter;
  48 class ScopedPtrAVFreePacket;
  49
  50 typedef scoped_ptr_malloc<AVPacket, ScopedPtrAVFreePacket> ScopedAVPacket;
  51
  52 class FFmpegDemuxerStream : public DemuxerStream {
  53  public:
  54   // Keeps a copy of |demuxer| and initializes itself using information
  55   // inside |stream|.  Both parameters must outlive |this|.
  56   FFmpegDemuxerStream(FFmpegDemuxer* demuxer, AVStream* stream);
  57
  58   // Enqueues the given AVPacket. It is invalid to queue a |packet| after
  59   // SetEndOfStream() has been called.
  60   void EnqueuePacket(ScopedAVPacket packet);
  61
  62   // Enters the end of stream state. After delivering remaining queued buffers
  63   // only end of stream buffers will be delivered.
  64   void SetEndOfStream();
  65
  66   // Drops queued buffers and clears end of stream state.
  67   void FlushBuffers();
  68
  69   // Empties the queues and ignores any additional calls to Read().
  70   void Stop();
  71
  72   // Returns the duration of this stream.
  73   base::TimeDelta duration();
  74
  75   // DemuxerStream implementation.
  76   virtual Type type() OVERRIDE;
  77   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  78   virtual void EnableBitstreamConverter() OVERRIDE;
  79   virtual const AudioDecoderConfig& audio_decoder_config() OVERRIDE;
  80   virtual const VideoDecoderConfig& video_decoder_config() OVERRIDE;
  81
  82   // Returns the range of buffered data in this stream.
  83   Ranges<base::TimeDelta> GetBufferedRanges() const;
  84
  85   // Returns elapsed time based on the already queued packets.
  86   // Used to determine stream duration when it's not known ahead of time.
  87   base::TimeDelta GetElapsedTime() const;
  88
  89   // Returns true if this stream has capacity for additional data.
  90   bool HasAvailableCapacity();
  91
  92  protected:
  93   virtual ~FFmpegDemuxerStream();
  94
  95  private:
  96   friend class FFmpegDemuxerTest;
  97
  98   // Runs |read_cb_| if present with the front of |buffer_queue_|, calling
  99   // NotifyCapacityAvailable() if capacity is still available.
 100   void SatisfyPendingRead();
 101
 102   // Converts an FFmpeg stream timestamp into a base::TimeDelta.
 103   static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
 104                                                 int64 timestamp);
 105
 106   FFmpegDemuxer* demuxer_;
 107   scoped_refptr<base::MessageLoopProxy> message_loop_;
 108   AVStream* stream_;
 109   AudioDecoderConfig audio_config_;
 110   VideoDecoderConfig video_config_;
 111   Type type_;
 112   base::TimeDelta duration_;
 113   bool stopped_;
 114   bool end_of_stream_;
 115   base::TimeDelta last_packet_timestamp_;
 116   Ranges<base::TimeDelta> buffered_ranges_;
 117
 118   DecoderBufferQueue buffer_queue_;
 119   ReadCB read_cb_;
 120
 121   scoped_ptr<FFmpegH264ToAnnexBBitstreamConverter> bitstream_converter_;
 122   bool bitstream_converter_enabled_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxerStream);
 125 };
 126
 127 class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
 128  public:
 129   FFmpegDemuxer(const scoped_refptr<base::MessageLoopProxy>& message_loop,
 130                 const scoped_refptr<DataSource>& data_source);
 131
 132   // Demuxer implementation.
 133   virtual void Initialize(DemuxerHost* host,
 134                           const PipelineStatusCB& status_cb) OVERRIDE;
 135   virtual void Stop(const base::Closure& callback) OVERRIDE;
 136   virtual void Seek(base::TimeDelta time, const PipelineStatusCB& cb) OVERRIDE;
 137   virtual void OnAudioRendererDisabled() OVERRIDE;
 138   virtual void SetPlaybackRate(float playback_rate) OVERRIDE;
 139   virtual scoped_refptr<DemuxerStream> GetStream(
 140       DemuxerStream::Type type) OVERRIDE;
 141   virtual base::TimeDelta GetStartTime() const OVERRIDE;
 142
 143   // Allow FFmpegDemuxerStream to notify us when there is updated information
 144   // about capacity and what buffered data is available.
 145   void NotifyCapacityAvailable();
 146   void NotifyBufferingChanged();
 147
 148  private:
 149   // To allow tests access to privates.
 150   friend class FFmpegDemuxerTest;
 151
 152   virtual ~FFmpegDemuxer();
 153
 154   // FFmpeg callbacks during initialization.
 155   void OnOpenContextDone(const PipelineStatusCB& status_cb, bool result);
 156   void OnFindStreamInfoDone(const PipelineStatusCB& status_cb, int result);
 157
 158   // FFmpeg callbacks during seeking.
 159   void OnSeekFrameDone(const PipelineStatusCB& cb, int result);
 160
 161   // FFmpeg callbacks during reading + helper method to initiate reads.
 162   void ReadFrameIfNeeded();
 163   void OnReadFrameDone(ScopedAVPacket packet, int result);
 164
 165   // DataSource callbacks during stopping.
 166   void OnDataSourceStopped(const base::Closure& callback);
 167
 168   // Returns true iff any stream has additional capacity. Note that streams can
 169   // go over capacity depending on how the file is muxed.
 170   bool StreamsHaveAvailableCapacity();
 171
 172   // Signal all FFmpegDemuxerStreams that the stream has ended.
 173   void StreamHasEnded();
 174
 175   // Called by |url_protocol_| whenever |data_source_| returns a read error.
 176   void OnDataSourceError();
 177
 178   // Returns the stream from |streams_| that matches |type| as an
 179   // FFmpegDemuxerStream.
 180   scoped_refptr<FFmpegDemuxerStream> GetFFmpegStream(
 181       DemuxerStream::Type type) const;
 182
 183   DemuxerHost* host_;
 184
 185   scoped_refptr<base::MessageLoopProxy> message_loop_;
 186
 187   // Thread on which all blocking FFmpeg operations are executed.
 188   base::Thread blocking_thread_;
 189
 190   // Tracks if there's an outstanding av_read_frame() operation.
 191   //
 192   // TODO(scherkus): Allow more than one read in flight for higher read
 193   // throughput using demuxer_bench to verify improvements.
 194   bool pending_read_;
 195
 196   // Tracks if there's an outstanding av_seek_frame() operation. Used to discard
 197   // results of pre-seek av_read_frame() operations.
 198   bool pending_seek_;
 199
 200   // |streams_| mirrors the AVStream array in |format_context_|. It contains
 201   // FFmpegDemuxerStreams encapsluating AVStream objects at the same index.
 202   //
 203   // Since we only support a single audio and video stream, |streams_| will
 204   // contain NULL entries for additional audio/video streams as well as for
 205   // stream types that we do not currently support.
 206   //
 207   // Once initialized, operations on FFmpegDemuxerStreams should be carried out
 208   // on the demuxer thread.
 209   typedef std::vector<scoped_refptr<FFmpegDemuxerStream> > StreamVector;
 210   StreamVector streams_;
 211
 212   // Reference to the data source. Asynchronous read requests are submitted to
 213   // this object.
 214   scoped_refptr<DataSource> data_source_;
 215
 216   // Derived bitrate after initialization has completed.
 217   int bitrate_;
 218
 219   // The first timestamp of the opened media file. This is used to set the
 220   // starting clock value to match the timestamps in the media file. Default
 221   // is 0.
 222   base::TimeDelta start_time_;
 223
 224   // Whether audio has been disabled for this demuxer (in which case this class
 225   // drops packets destined for AUDIO demuxer streams on the floor).
 226   bool audio_disabled_;
 227
 228   // Set if we know duration of the audio stream. Used when processing end of
 229   // stream -- at this moment we definitely know duration.
 230   bool duration_known_;
 231
 232   // FFmpegURLProtocol implementation and corresponding glue bits.
 233   BlockingUrlProtocol url_protocol_;
 234   scoped_ptr<FFmpegGlue> glue_;
 235
 236   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 237 };
 238
 239 }  // namespace media
 240
 241 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_