mirror of https://git.ffmpeg.org/ffmpeg.git
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
/*
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* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Range decoder functions common to VP8 and VP9
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*/
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#ifndef AVCODEC_VP89_RAC_H
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#define AVCODEC_VP89_RAC_H
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#include <stdint.h>
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#include "libavutil/attributes.h"
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#include "vpx_rac.h"
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// rounding is different than vpx_rac_get, is vpx_rac_get wrong?
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static av_always_inline int vp89_rac_get(VPXRangeCoder *c)
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{
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return vpx_rac_get_prob(c, 128);
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}
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static av_unused int vp89_rac_get_uint(VPXRangeCoder *c, int bits)
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{
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int value = 0;
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while (bits--) {
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value = (value << 1) | vp89_rac_get(c);
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}
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return value;
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}
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// how probabilities are associated with decisions is different I think
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// well, the new scheme fits in the old but this way has one fewer branches per decision
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static av_always_inline int vp89_rac_get_tree(VPXRangeCoder *c, const int8_t (*tree)[2],
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const uint8_t *probs)
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{
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int i = 0;
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do {
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i = tree[i][vpx_rac_get_prob(c, probs[i])];
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} while (i > 0);
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return -i;
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}
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#endif /* AVCODEC_VP89_RAC_H */
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