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      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 #ifndef MEDIA_WEBM_WEBM_CLUSTER_PARSER_H_
      6 #define MEDIA_WEBM_WEBM_CLUSTER_PARSER_H_
      7 
      8 #include <deque>
      9 #include <map>
     10 #include <set>
     11 #include <string>
     12 
     13 #include "base/memory/scoped_ptr.h"
     14 #include "media/base/media_export.h"
     15 #include "media/base/media_log.h"
     16 #include "media/base/stream_parser_buffer.h"
     17 #include "media/webm/webm_parser.h"
     18 #include "media/webm/webm_tracks_parser.h"
     19 
     20 namespace media {
     21 
     22 class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
     23  private:
     24   // Helper class that manages per-track state.
     25   class Track {
     26    public:
     27     Track(int track_num, bool is_video);
     28     ~Track();
     29 
     30     int track_num() const { return track_num_; }
     31     const std::deque<scoped_refptr<StreamParserBuffer> >& buffers() const {
     32       return buffers_;
     33     }
     34 
     35     bool AddBuffer(const scoped_refptr<StreamParserBuffer>& buffer);
     36 
     37     // Clears all buffer state.
     38     void Reset();
     39 
     40     // Helper function used to inspect block data to determine if the
     41     // block is a keyframe.
     42     // |data| contains the bytes in the block.
     43     // |size| indicates the number of bytes in |data|.
     44     bool IsKeyframe(const uint8* data, int size) const;
     45 
     46    private:
     47     int track_num_;
     48     std::deque<scoped_refptr<StreamParserBuffer> > buffers_;
     49     bool is_video_;
     50   };
     51 
     52   typedef std::map<int, Track> TextTrackMap;
     53 
     54  public:
     55   typedef std::deque<scoped_refptr<StreamParserBuffer> > BufferQueue;
     56 
     57   class MEDIA_EXPORT TextTrackIterator {
     58    public:
     59     explicit TextTrackIterator(const TextTrackMap& text_track_map);
     60     TextTrackIterator(const TextTrackIterator& rhs);
     61     ~TextTrackIterator();
     62 
     63     // To visit each text track.  If the iterator is exhausted, it returns
     64     // as parameters the values 0 and NULL, and the function returns false.
     65     // Otherwise, it returns the buffers for the associated track, and the
     66     // function returns true.
     67     bool operator()(int* track_num, const BufferQueue** buffers);
     68    private:
     69     TextTrackIterator& operator=(const TextTrackIterator&);
     70 
     71     TextTrackMap::const_iterator iterator_;
     72     const TextTrackMap::const_iterator iterator_end_;
     73   };
     74 
     75   WebMClusterParser(int64 timecode_scale,
     76                     int audio_track_num,
     77                     int video_track_num,
     78                     const WebMTracksParser::TextTracks& text_tracks,
     79                     const std::set<int64>& ignored_tracks,
     80                     const std::string& audio_encryption_key_id,
     81                     const std::string& video_encryption_key_id,
     82                     const LogCB& log_cb);
     83   virtual ~WebMClusterParser();
     84 
     85   // Resets the parser state so it can accept a new cluster.
     86   void Reset();
     87 
     88   // Parses a WebM cluster element in |buf|.
     89   //
     90   // Returns -1 if the parse fails.
     91   // Returns 0 if more data is needed.
     92   // Returns the number of bytes parsed on success.
     93   int Parse(const uint8* buf, int size);
     94 
     95   base::TimeDelta cluster_start_time() const { return cluster_start_time_; }
     96   const BufferQueue& audio_buffers() const { return audio_.buffers(); }
     97   const BufferQueue& video_buffers() const { return video_.buffers(); }
     98 
     99   // Returns an iterator object, allowing each text track to be visited.
    100   TextTrackIterator CreateTextTrackIterator() const;
    101 
    102   // Returns true if the last Parse() call stopped at the end of a cluster.
    103   bool cluster_ended() const { return cluster_ended_; }
    104 
    105  private:
    106   // WebMParserClient methods.
    107   virtual WebMParserClient* OnListStart(int id) OVERRIDE;
    108   virtual bool OnListEnd(int id) OVERRIDE;
    109   virtual bool OnUInt(int id, int64 val) OVERRIDE;
    110   virtual bool OnBinary(int id, const uint8* data, int size) OVERRIDE;
    111 
    112   bool ParseBlock(bool is_simple_block, const uint8* buf, int size,
    113                   const uint8* additional, int additional_size, int duration);
    114   bool OnBlock(bool is_simple_block, int track_num, int timecode, int duration,
    115                int flags, const uint8* data, int size,
    116                const uint8* additional, int additional_size);
    117 
    118   // Resets the Track objects associated with each text track.
    119   void ResetTextTracks();
    120 
    121   // Search for the indicated track_num among the text tracks.  Returns NULL
    122   // if that track num is not a text track.
    123   Track* FindTextTrack(int track_num);
    124 
    125   double timecode_multiplier_;  // Multiplier used to convert timecodes into
    126                                 // microseconds.
    127   std::set<int64> ignored_tracks_;
    128   std::string audio_encryption_key_id_;
    129   std::string video_encryption_key_id_;
    130 
    131   WebMListParser parser_;
    132 
    133   int64 last_block_timecode_;
    134   scoped_ptr<uint8[]> block_data_;
    135   int block_data_size_;
    136   int64 block_duration_;
    137   int64 block_add_id_;
    138   scoped_ptr<uint8[]> block_additional_data_;
    139   int block_additional_data_size_;
    140 
    141   int64 cluster_timecode_;
    142   base::TimeDelta cluster_start_time_;
    143   bool cluster_ended_;
    144 
    145   Track audio_;
    146   Track video_;
    147   TextTrackMap text_track_map_;
    148   LogCB log_cb_;
    149 
    150   DISALLOW_IMPLICIT_CONSTRUCTORS(WebMClusterParser);
    151 };
    152 
    153 }  // namespace media
    154 
    155 #endif  // MEDIA_WEBM_WEBM_CLUSTER_PARSER_H_
    156