vp89_rac.h (1846B)
1 /* 2 * Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 /** 22 * @file 23 * Range decoder functions common to VP8 and VP9 24 */ 25 26 #ifndef AVCODEC_VP89_RAC_H 27 #define AVCODEC_VP89_RAC_H 28 29 #include <stdint.h> 30 31 #include "libavutil/attributes.h" 32 33 #include "vpx_rac.h" 34 35 // rounding is different than vpx_rac_get, is vpx_rac_get wrong? 36 static av_always_inline int vp89_rac_get(VPXRangeCoder *c) 37 { 38 return vpx_rac_get_prob(c, 128); 39 } 40 41 static av_unused int vp89_rac_get_uint(VPXRangeCoder *c, int bits) 42 { 43 int value = 0; 44 45 while (bits--) { 46 value = (value << 1) | vp89_rac_get(c); 47 } 48 49 return value; 50 } 51 52 // how probabilities are associated with decisions is different I think 53 // well, the new scheme fits in the old but this way has one fewer branches per decision 54 static av_always_inline int vp89_rac_get_tree(VPXRangeCoder *c, const int8_t (*tree)[2], 55 const uint8_t *probs) 56 { 57 int i = 0; 58 59 do { 60 i = tree[i][vpx_rac_get_prob(c, probs[i])]; 61 } while (i > 0); 62 63 return -i; 64 } 65 66 #endif /* AVCODEC_VP89_RAC_H */