Adding ChunkDemuxer implementation.

media/filters/chunk_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_CHUNK_DEMUXER_H_
+#define MEDIA_FILTERS_CHUNK_DEMUXER_H_
+
+#include <list>
+
+#include "base/synchronization/lock.h"
+#include "media/base/filter_factories.h"
+#include "media/base/filters.h"
+#include "media/webm/webm_parser.h"
+
+struct AVFormatContext;
+
+namespace media {
+
+class ChunkDemuxer;
+class ChunkDemuxerStream;
+
+// Class used by an external object to send media data to the
+// Demuxer. This object is created by the DemuxerFactory and
+// contains the Demuxer that will be returned in the next Build()
+// call on the factory. The external object tells the factory
+// to create one of these objects before it starts the Pipeline.
+// It does this because the external object may need to make AddData()
+// calls before the pipeline has completely initialized. This class
+// allows data from these calls to be queued until initialization
+// completes. It represents the minimal operations needed by
+// the external object to talk to the Demuxer. It also allows
+// the external object to have a longer lifetime than the pipeline.
+class MediaDataSink {
+ public:
+  MediaDataSink(const scoped_refptr<ChunkDemuxer>& demuxer);
+  ~MediaDataSink();
+
+  // Flush all data passed via AddData().
+  void Flush();
+
+  // Sends media data to the demuxer. Returns true if the data is valid.
+  bool AddData(const uint8* data, unsigned length);
+
+  // Signals that playback is shutting down and further AddData() calls
+  // should fail. This also cancels pending Read()s on DemuxerStreams.
+  void Shutdown();
+
+ private:
+  scoped_refptr<ChunkDemuxer> demuxer_;
+};

[scherkus (not reviewing), 2011/06/23 18:50:18]

DISALLOW etc

[acolwell GONE FROM CHROMIUM, 2011/06/23 22:42:17]

Done.

+
+class ChunkDemuxer : public Demuxer {
+ public:
+  ChunkDemuxer();
+  virtual ~ChunkDemuxer();
+
+  bool Init(const uint8* data, int size);
+
+  // Filter implementation.
+  virtual void set_host(FilterHost* filter_host);
+  virtual void Stop(FilterCallback* callback);
+  virtual void Seek(base::TimeDelta time, const FilterStatusCB&  cb);
+  virtual void OnAudioRendererDisabled();
+  virtual void SetPreload(Preload preload);
+
+  // Demuxer implementation.
+  virtual scoped_refptr<DemuxerStream> GetStream(DemuxerStream::Type type);
+  virtual base::TimeDelta GetStartTime() const;
+
+  // Methods used by MediaDataSink
+  void FlushData();
+  bool AddData(const uint8* data, unsigned length);
+  void Shutdown();
+
+ private:
+  // Helper class that collects information from the INFO & TRACKS elements
+  // passed to Init().
+  class InfoTrackWebMParserClient : public WebMParserClient {

[scherkus (not reviewing), 2011/06/23 18:50:18]

any reason why we can't break this out into media/webm?

[acolwell GONE FROM CHROMIUM, 2011/06/23 22:42:17]

This implementation is specific to this demuxer. For example it only allows a
single audio & video stream and only selects fields that are important to this
demuxer. I think media/webm should be reserved for code that is of more general
utility.

+   public:
+    InfoTrackWebMParserClient();
+
+    int64 timecode_scale() const;
+    double duration() const;
+    int64 audio_track_num() const;
+    int64 audio_default_duration() const;
+    int64 video_track_num() const;
+    int64 video_default_duration() const;

[scherkus (not reviewing), 2011/06/23 18:50:18]

none of these durations mention the units

why not convert to base::TimeDelta during parsing then everything is
self-documenting?

[acolwell GONE FROM CHROMIUM, 2011/06/23 22:42:17]

Done.

+
+    // WebMParserClient methods
+    virtual bool OnListStart(int id);
+    virtual bool OnListEnd(int id);
+    virtual bool OnUInt(int id, int64 val);
+    virtual bool OnFloat(int id, double val);
+    virtual bool OnBinary(int id, const uint8* data, int size);
+    virtual bool OnString(int id, const std::string& str);
+    virtual bool OnSimpleBlock(int track_num, int timecode,
+                               int flags,
+                               const uint8* data, int size);
+   private:
+    int64 timecode_scale_;
+    double duration_;
+    int64 track_type_;
+    int64 track_num_;
+    int64 track_default_duration_;
+    int64 audio_track_num_;
+    int64 audio_default_duration_;
+    int64 video_track_num_;
+    int64 video_default_duration_;
+  };
+
+  enum State {
+    WAITING_FOR_INIT,
+    INITIALIZED,
+    INIT_ERROR,
+    SHUTDOWN,
+  };
+
+  void ChangeState(State new_state);
+
+  // Generates an AVFormatContext for the INFO & TRACKS elements contained
+  // in |data|. Returns NULL if parsing |data| fails.
+  AVFormatContext* CreateFormatContext(const uint8* data, int size) const;
+
+  // Sets up |audio_| & |video_| DemuxerStreams based on the data in
+  // |format_context_|. Returns false if no valid audio or video stream were
+  // found.
+  bool SetupStreams();
+
+  // Parse all the buffers in |pending_buffers_|. Returns false if parsing one
+  // of the buffers fails.
+  bool ParsePendingBuffers();
+
+  // Parse a buffer that was passed to AddData(). |data| is expected to contain
+  // one or more WebM Clusters. Returns false if parsing the data fails.
+  bool ParseAndAddData_Locked(const uint8* data, int length);
+
+  base::Lock lock_;
+  State state_;
+
+  base::TimeDelta seek_time_;
+  FilterStatusCB seek_cb_;
+
+  scoped_refptr<ChunkDemuxerStream> audio_;
+  scoped_refptr<ChunkDemuxerStream> video_;
+
+  AVFormatContext* format_context_;
+
+  int64 buffered_bytes_;
+
+  bool first_seek_;
+  base::TimeDelta duration_;
+
+  InfoTrackWebMParserClient info_;
+
+  typedef std::list<scoped_refptr<media::Buffer> > BufferList;
+  BufferList pending_buffers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChunkDemuxer);
+};
+
+class ChunkDemuxerFactory : public DemuxerFactory {
+ public:
+  // Takes a reference to |demuxer_factory|.
+  ChunkDemuxerFactory(DataSourceFactory* data_source_factory);
+  virtual ~ChunkDemuxerFactory();
+
+  bool IsUrlSupported(const std::string& url) const;
+  MediaDataSink* CreateMediaDataSink();
+
+  // DemuxerFactory methods.
+  virtual void Build(const std::string& url, BuildCallback* cb);
+  virtual DemuxerFactory* Clone() const;
+
+ private:
+  static const char kURLPrefix[];
+  class BuildState;
+
+  scoped_ptr<DataSourceFactory> data_source_factory_;
+  scoped_refptr<ChunkDemuxer> demuxer_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ChunkDemuxerFactory);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_FILTERS_CHUNK_DEMUXER_H_