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ffmpeg-4.2.2/libavcodec/elsdec.h 1.72 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * ELS (Entropy Logarithmic-Scale) decoder
   *
   * Copyright (c) 2013 Maxim Poliakovski
   *
   * 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
   * Entropy Logarithmic-Scale binary arithmetic coder
   */
  
  #ifndef AVCODEC_ELSDEC_H
  #define AVCODEC_ELSDEC_H
  
  #include <stdint.h>
  #include <sys/types.h>
  
  #define ELS_EXPGOLOMB_LEN   10
  
  typedef struct ElsDecCtx {
      const uint8_t *in_buf;
      unsigned x;
      size_t data_size;
      int j, t, diff, err;
  } ElsDecCtx;
  
  typedef struct ElsRungNode {
      uint8_t  rung;
      uint16_t next_index;
  } ElsRungNode;
  
  typedef struct ElsUnsignedRung {
      uint8_t      prefix_rung[ELS_EXPGOLOMB_LEN + 1];
      ElsRungNode  *rem_rung_list;
      size_t       rung_list_size;
      uint16_t     avail_index;
  } ElsUnsignedRung;
  
  void ff_els_decoder_init(ElsDecCtx *ctx, const uint8_t *in, size_t data_size);
  void ff_els_decoder_uninit(ElsUnsignedRung *rung);
  int  ff_els_decode_bit(ElsDecCtx *ctx, unsigned char *rung);
  unsigned ff_els_decode_unsigned(ElsDecCtx *ctx, ElsUnsignedRung *ur);
  
  #endif /* AVCODEC_ELSDEC_H */