media/formats/mp2t/es_parser.h

   1 // Copyright 2014 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_FORMATS_MP2T_ES_PARSER_H_
   6 #define MEDIA_FORMATS_MP2T_ES_PARSER_H_
   7
   8 #include <list>
   9 #include <utility>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/time/time.h"
  15 #include "media/base/media_export.h"
  16 #include "media/base/stream_parser_buffer.h"
  17
  18 namespace media {
  19
  20 class OffsetByteQueue;
  21 class StreamParserBuffer;
  22
  23 namespace mp2t {
  24
  25 class MEDIA_EXPORT EsParser {
  26  public:
  27   typedef base::Callback<void(scoped_refptr<StreamParserBuffer>)> EmitBufferCB;
  28
  29   EsParser();
  30   virtual ~EsParser();
  31
  32   // ES parsing.
  33   // Should use kNoTimestamp when a timestamp is not valid.
  34   bool Parse(const uint8* buf, int size,
  35              base::TimeDelta pts,
  36              DecodeTimestamp dts);
  37
  38   // Flush any pending buffer.
  39   virtual void Flush() = 0;
  40
  41   // Reset the state of the ES parser.
  42   void Reset();
  43
  44  protected:
  45   struct TimingDesc {
  46     TimingDesc();
  47     TimingDesc(DecodeTimestamp dts, base::TimeDelta pts);
  48
  49     DecodeTimestamp dts;
  50     base::TimeDelta pts;
  51   };
  52
  53   // Parse ES data from |es_queue_|.
  54   // Return true when successful.
  55   virtual bool ParseFromEsQueue() = 0;
  56
  57   // Reset the internal state of the ES parser.
  58   virtual void ResetInternal() = 0;
  59
  60   // Get the timing descriptor with the largest byte count that is less or
  61   // equal to |es_byte_count|.
  62   // This timing descriptor and all the ones that come before (in stream order)
  63   // are removed from list |timing_desc_list_|.
  64   // If no timing descriptor is found, then the default TimingDesc is returned.
  65   TimingDesc GetTimingDescriptor(int64 es_byte_count);
  66
  67   // Bytes of the ES stream that have not been emitted yet.
  68   scoped_ptr<media::OffsetByteQueue> es_queue_;
  69
  70  private:
  71   // Anchor some timing information into the ES queue.
  72   // Here are two examples how this timing info is applied according to
  73   // the MPEG-2 TS spec - ISO/IEC 13818:
  74   // - "In the case of audio, if a PTS is present in PES packet header it shall
  75   // refer to the first access unit commencing in the PES packet. An audio
  76   // access unit commences in a PES packet if the first byte of the audio
  77   // access unit is present in the PES packet."
  78   // - "For AVC video streams conforming to one or more profiles defined
  79   // in Annex A of Rec. ITU-T H.264 | ISO/IEC 14496-10 video, if a PTS is
  80   // present in the PES packet header, it shall refer to the first AVC access
  81   // unit that commences in this PES packet.
  82   std::list<std::pair<int64, TimingDesc> > timing_desc_list_;
  83
  84   DISALLOW_COPY_AND_ASSIGN(EsParser);
  85 };
  86
  87 }  // namespace mp2t
  88 }  // namespace media
  89
  90 #endif