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ffmpeg-4.2.2/libavcodec/cabac.h 1.69 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
   * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * Context Adaptive Binary Arithmetic Coder.
   */
  
  #ifndef AVCODEC_CABAC_H
  #define AVCODEC_CABAC_H
  
  #include <stdint.h>
  
  #include "put_bits.h"
  
  extern const uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
  #define H264_NORM_SHIFT_OFFSET 0
  #define H264_LPS_RANGE_OFFSET 512
  #define H264_MLPS_STATE_OFFSET 1024
  #define H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET 1280
  
  #define CABAC_BITS 16
  #define CABAC_MASK ((1<<CABAC_BITS)-1)
  
  typedef struct CABACContext{
      int low;
      int range;
      int outstanding_count;
      const uint8_t *bytestream_start;
      const uint8_t *bytestream;
      const uint8_t *bytestream_end;
      PutBitContext pb;
  }CABACContext;
  
  void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
  int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size);
  
  #endif /* AVCODEC_CABAC_H */