Initial implementation of stream switching in AdaptiveDemuxer.

media/filters/adaptive_demuxer.h

 // Copyright (c) 2011 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 a Demuxer that can switch among different data sources mid-stream.
 // Uses FFmpegDemuxer under the covers, so see the caveats at the top of
 // ffmpeg_demuxer.h.
 
 #ifndef MEDIA_FILTERS_ADAPTIVE_DEMUXER_H_
 #define MEDIA_FILTERS_ADAPTIVE_DEMUXER_H_
 
 #include <deque>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/synchronization/lock.h"
 #include "media/base/buffers.h"
 #include "media/base/filter_factories.h"
 #include "media/base/filters.h"
 #include "media/base/pipeline.h"
 #include "media/base/media_format.h"
 
 namespace media {
 
 class AdaptiveDemuxer;
+class StreamSwitchManager;
 
 class AdaptiveDemuxerStream : public DemuxerStream {
  public:
   typedef std::vector<scoped_refptr<DemuxerStream> > StreamVector;
+  typedef std::deque<ReadCallback> ReadCBQueue;
+
+  // Typedefs used by the stream switching code to seek a stream to a desired
+  // location. The AdaptiveDemuxer constructs a SeekFunction for the stream
+  // being switched to and passes this function to
+  // AdaptiveDemuxerStream::ChangeCurrentStream(). For more information about
+  // how the SeekFunction is implemented, look at the comments for
+  // AdaptiveDemuxer::StartStreamSwitchSeek() below.
+  //
+  // Callback for SeekFunction. The PipelineStatus parameter indicates whether
+  // the seek was successful or not. The base::TimeDelta parameter indicates the
+  // time we actually seeked to. If the seek was successful this should be >=
+  // than the requested time.
+  typedef base::Callback<void(base::TimeDelta, PipelineStatus)> SeekFunctionCB;
+
+  // Wraps a function that performs a seek on a specified stream. The
+  // base::TimeDelta parameter indicates what time to seek to. The
+  // SeekFunctionCBparameter specifies the callback we want called when the seek
+  // completes.
+  typedef base::Callback<void(base::TimeDelta, SeekFunctionCB)> SeekFunction;
 
   // Keeps references to the passed-in streams.  |streams| must be non-empty and
   // all the streams in it must agree on type and media_format (or be NULL).
   // |initial_stream| must be a valid index into |streams| and specifies the
   // current stream on construction.
   AdaptiveDemuxerStream(StreamVector const& streams, int initial_stream);
   virtual ~AdaptiveDemuxerStream();
 
+  // Notifies this stream that a Seek() was requested on the demuxer.
+  void OnAdaptiveDemuxerSeek(base::TimeDelta seek_time);
+
   // Change the stream to satisfy subsequent Read() requests from.  The
-  // referenced pointer must not be NULL.
-  void ChangeCurrentStream(int index);
+  // referenced pointer must not be NULL. The SeekFunction parameter
+  // provides a way to seek |streams_[index]| to a specific time.
+  void ChangeCurrentStream(int index, const SeekFunction& seek_function,
+                           const PipelineStatusCB& cb);
 
   // DemuxerStream methods.
   virtual void Read(const ReadCallback& read_callback);
   virtual Type type();
   virtual const MediaFormat& media_format();
   virtual void EnableBitstreamConverter();
   virtual AVStream* GetAVStream();
 
  private:
   // Returns a pointer to the current stream.
   DemuxerStream* current_stream();
 
   // DEBUG_MODE-only CHECK that the data members are in a reasonable state.
   void DCheckSanity();
 
+  void OnReadDone(Buffer* buffer);
+
+  bool IsSwitchPending_Locked() const;
+  bool CanStartSwitch_Locked() const;
+
+  // Starts the stream switch. This method expects that no Read()s are
+  // outstanding on |streams_[current_stream_index_]|.
+  void StartSwitch();
+
+  // Called by the SeekFunction when it has completed the seek on
+  // |streams_[switch_index_]|.
+  void OnSwitchSeekDone(base::TimeDelta seek_time, PipelineStatus status);
+
   StreamVector streams_;
   // Guards the members below.  Only held for simple variable reads/writes, not
   // during async operation.
   base::Lock lock_;
   int current_stream_index_;
   bool bitstream_converter_enabled_;
 
+  // The number of outstanding Read()'s on |streams_[current_stream_index_]|.
+  int pending_reads_;
+
+  // A queue of callback objects passed to Read().
+  ReadCBQueue read_cb_queue_;
+
+  // Callback passed to ChangeCurrentStream(). This is called & reset when the
+  // stream switch has completed. Callback object is null when a stream switch
+  // is not in progress.
+  PipelineStatusCB switch_cb_;
+
+  // The index of the stream we are switching to. During a stream switch
+  // 0 <= |switch_index_| < |streams_.size()| and
+  // |streams_[switch_index]| MUST NOT be null. |switch_index_| is set to -1 if
+  // a stream switch is not in progress.
+  int switch_index_;
+
+  // Function used to seek |streams_[switch_index_]| to a specific time. The
+  // callback is null if a switch is not pending.
+  SeekFunction switch_seek_function_;
+
+  // The timestamp of the last buffer returned via a Read() callback.
+  base::TimeDelta last_buffer_timestamp_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(AdaptiveDemuxerStream);
 };
 
 class AdaptiveDemuxer : public Demuxer {
  public:
   typedef std::vector<scoped_refptr<Demuxer> > DemuxerVector;
 
   // |demuxers| must be non-empty, and the index arguments must be valid indexes
   // into |demuxers|, or -1 to indicate no demuxer is serving that type.
   AdaptiveDemuxer(DemuxerVector const& demuxers,
                   int initial_audio_demuxer_index,
                   int initial_video_demuxer_index);
   virtual ~AdaptiveDemuxer();
 
-  // Change which demuxers the streams will use.
-  void ChangeCurrentDemuxer(int audio_index, int video_index);
+  // Change to a different video stream.
+  void ChangeVideoStream(int video_id, const PipelineStatusCB& done_cb);
+
+  // Get the ID of the current video stream.
+  int GetCurrentVideoId() const;
 
   // Filter implementation.
   virtual void Stop(FilterCallback* callback);
   virtual void Seek(base::TimeDelta time, const FilterStatusCB&  cb);
   virtual void OnAudioRendererDisabled();
   virtual void set_host(FilterHost* filter_host);
   virtual void SetPlaybackRate(float playback_rate);
   virtual void SetPreload(Preload preload);
 
   // Demuxer implementation.
   virtual scoped_refptr<DemuxerStream> GetStream(DemuxerStream::Type type);
 
  private:
   // Returns a pointer to the currently active demuxer of the given type.
   Demuxer* current_demuxer(DemuxerStream::Type type);
 
+  // Called when the AdaptiveDemuxerStream completes a stream switch.
+  void ChangeVideoStreamDone(int new_stream_index,
+                             const PipelineStatusCB& done_cb,
+                             PipelineStatus status);
+
+  // Methods for SeekFunction.
+  //
+  // Seeking on a stream follows the flow below.
+  //
+  // SeekFunction.Run() -> StartStreamSwitchSeek()
+  //                              |
+  //                              V
+  //                      +--------------+
+  //                      | Found Switch |
+  //                      |  Point in    | No  (Seeking to get more index data.)
+  //                      | Index Data?  |---> |demuxers_[stream_index]->Seek()|
+  //                      +--------------+                    |
+  //                              |Yes                        V
+  //                              |                   OnIndexSeekDone()
+  //                              |                           |
+  //                              V                           V
+  //            (Seeking stream to switch point.)  Yes  +--------------+
+  //           |demuxers_[stream_index]->Seek()| <------| Found Switch |
+  //                              |                     |  Point in    |
+  //                              |                     | Index Data?  |
+  //                              |                     +--------------+
+  //                              |                           | No
+  //                              V                           V
+  //                        OnStreamSeekDone()         seek_cb(ERROR)
+  //                              |
+  //                              V
+  //                           seek_cb(OK | ERROR)
+  //
+  // When AdaptiveDemuxer creates a SeekFunction object it points to this
+  // method.
+  void StartStreamSwitchSeek(
+      DemuxerStream::Type type,
+      int stream_index,
+      base::TimeDelta seek_time,
+      const AdaptiveDemuxerStream::SeekFunctionCB& seek_cb);
+
+  // Called when the seek for index data initiated by StartStreamSwitchSeek()
+  // completes.
+  void OnIndexSeekDone(DemuxerStream::Type type,
+                       int stream_index,
+                       base::TimeDelta seek_time,
+                       const AdaptiveDemuxerStream::SeekFunctionCB& seek_cb,
+                       PipelineStatus status);
+
+  // Called when the stream seek initiated by StartStreamSwitchSeek() or
+  // OnIndexSeekDone() completes.
+  static void OnStreamSeekDone(
+      const AdaptiveDemuxerStream::SeekFunctionCB& seek_cb,
+      base::TimeDelta seek_point,
+      PipelineStatus status);
+
   DemuxerVector demuxers_;
   scoped_refptr<AdaptiveDemuxerStream> audio_stream_;
   scoped_refptr<AdaptiveDemuxerStream> video_stream_;
   // Guards the members below.  Only held for simple variable reads/writes, not
   // during async operation.
-  base::Lock lock_;
+  mutable base::Lock lock_;
   int current_audio_demuxer_index_;
   int current_video_demuxer_index_;
+  float playback_rate_;
+  bool switch_pending_;
+  scoped_refptr<StreamSwitchManager> stream_switch_manager_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AdaptiveDemuxer);
 };
 
 // AdaptiveDemuxerFactory wraps an underlying DemuxerFactory that knows how to
 // build demuxers for a single URL, and implements a primitive (for now) version
 // of multi-file manifests.  The manifest is encoded in the |url| parameter to
 // Build() as:
 // x-adaptive:<initial_audio_index>:<initial_video_index>:<URL>[^<URL>]* where
 // <URL>'s are "real" media URLs which are passed to the underlying
@@ skipping 14 matching lines @@
 
  private:
   scoped_ptr<DemuxerFactory> delegate_factory_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(AdaptiveDemuxerFactory);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_ADAPTIVE_DEMUXER_H_