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      1 // Copyright 2013 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_MP2T_ES_PARSER_H264_H_
      6 #define MEDIA_MP2T_ES_PARSER_H264_H_
      7 
      8 #include <list>
      9 #include <utility>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/callback.h"
     13 #include "base/compiler_specific.h"
     14 #include "base/time/time.h"
     15 #include "media/base/byte_queue.h"
     16 #include "media/base/video_decoder_config.h"
     17 #include "media/mp2t/es_parser.h"
     18 
     19 namespace media {
     20 class BitReader;
     21 class StreamParserBuffer;
     22 }
     23 
     24 namespace media {
     25 namespace mp2t {
     26 
     27 // Remark:
     28 // In this h264 parser, frame splitting is based on AUD nals.
     29 // Mpeg2 TS spec: "2.14 Carriage of Rec. ITU-T H.264 | ISO/IEC 14496-10 video"
     30 // "Each AVC access unit shall contain an access unit delimiter NAL Unit;"
     31 //
     32 class EsParserH264 : public EsParser {
     33  public:
     34   typedef base::Callback<void(const VideoDecoderConfig&)> NewVideoConfigCB;
     35 
     36   EsParserH264(const NewVideoConfigCB& new_video_config_cb,
     37                const EmitBufferCB& emit_buffer_cb);
     38   virtual ~EsParserH264();
     39 
     40   // EsParser implementation.
     41   virtual bool Parse(const uint8* buf, int size,
     42                      base::TimeDelta pts,
     43                      base::TimeDelta dts) OVERRIDE;
     44   virtual void Flush() OVERRIDE;
     45   virtual void Reset() OVERRIDE;
     46 
     47  private:
     48   struct TimingDesc {
     49     base::TimeDelta dts;
     50     base::TimeDelta pts;
     51   };
     52 
     53   // H264 parser.
     54   // It resumes parsing from byte position |es_pos_|.
     55   bool ParseInternal();
     56 
     57   // Emit a frame if a frame has been started earlier.
     58   void EmitFrameIfNeeded(int next_aud_pos);
     59 
     60   // Start a new frame.
     61   // Note: if aud_pos < 0, clear the current frame.
     62   void StartFrame(int aud_pos);
     63 
     64   // Discard |nbytes| of ES from the ES byte queue.
     65   void DiscardEs(int nbytes);
     66 
     67   // Parse a NAL / SPS.
     68   // Returns true if successful (compliant bitstream).
     69   bool NalParser(const uint8* buf, int size);
     70   bool ProcessSPS(const uint8* buf, int size);
     71 
     72   // Callbacks to pass the stream configuration and the frames.
     73   NewVideoConfigCB new_video_config_cb_;
     74   EmitBufferCB emit_buffer_cb_;
     75 
     76   // Bytes of the ES stream that have not been emitted yet.
     77   ByteQueue es_byte_queue_;
     78   std::list<std::pair<int, TimingDesc> > timing_desc_list_;
     79 
     80   // H264 parser state.
     81   // Note: |current_access_unit_pos_| is pointing to an annexB syncword
     82   // while |current_nal_pos_| is pointing to the NAL unit
     83   // (i.e. does not include the annexB syncword).
     84   int es_pos_;
     85   int current_nal_pos_;
     86   int current_access_unit_pos_;
     87   bool is_key_frame_;
     88 
     89   // Last video decoder config.
     90   VideoDecoderConfig last_video_decoder_config_;
     91 };
     92 
     93 }  // namespace mp2t
     94 }  // namespace media
     95 
     96 #endif
     97 
     98