libavcodec/ffv1_template.c

   1 /*
   2  * FFV1 codec
   3  *
   4  * Copyright (c) 2003-2013 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 static inline int RENAME(predict)(TYPE *src, TYPE *last)
  24 {
  25     const int LT = last[-1];
  26     const int T  = last[0];
  27     const int L  = src[-1];
  28
  29     return mid_pred(L, L + T - LT, T);
  30 }
  31
  32 static inline int RENAME(get_context)(const int16_t quant_table[MAX_CONTEXT_INPUTS][MAX_QUANT_TABLE_SIZE],
  33                                       TYPE *src, TYPE *last, TYPE *last2)
  34 {
  35     const int LT = last[-1];
  36     const int T  = last[0];
  37     const int RT = last[1];
  38     const int L  = src[-1];
  39
  40     if (quant_table[3][127] || quant_table[4][127]) {
  41         const int TT = last2[0];
  42         const int LL = src[-2];
  43         return quant_table[0][(L - LT) & MAX_QUANT_TABLE_MASK] +
  44                quant_table[1][(LT - T) & MAX_QUANT_TABLE_MASK] +
  45                quant_table[2][(T - RT) & MAX_QUANT_TABLE_MASK] +
  46                quant_table[3][(LL - L) & MAX_QUANT_TABLE_MASK] +
  47                quant_table[4][(TT - T) & MAX_QUANT_TABLE_MASK];
  48     } else
  49         return quant_table[0][(L - LT) & MAX_QUANT_TABLE_MASK] +
  50                quant_table[1][(LT - T) & MAX_QUANT_TABLE_MASK] +
  51                quant_table[2][(T - RT) & MAX_QUANT_TABLE_MASK];
  52 }
  53