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ffmpeg-4.2.2/libavcodec/ffv1_template.c 1.77 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * FFV1 codec
   *
   * Copyright (c) 2003-2013 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
   */
  
  static inline int RENAME(predict)(TYPE *src, TYPE *last)
  {
      const int LT = last[-1];
      const int T  = last[0];
      const int L  = src[-1];
  
      return mid_pred(L, L + T - LT, T);
  }
  
  static inline int RENAME(get_context)(PlaneContext *p, TYPE *src,
                                        TYPE *last, TYPE *last2)
  {
      const int LT = last[-1];
      const int T  = last[0];
      const int RT = last[1];
      const int L  = src[-1];
  
      if (p->quant_table[3][127]) {
          const int TT = last2[0];
          const int LL = src[-2];
          return p->quant_table[0][(L - LT) & 0xFF] +
                 p->quant_table[1][(LT - T) & 0xFF] +
                 p->quant_table[2][(T - RT) & 0xFF] +
                 p->quant_table[3][(LL - L) & 0xFF] +
                 p->quant_table[4][(TT - T) & 0xFF];
      } else
          return p->quant_table[0][(L - LT) & 0xFF] +
                 p->quant_table[1][(LT - T) & 0xFF] +
                 p->quant_table[2][(T - RT) & 0xFF];
  }