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/*
* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
*
* 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
* Range decoder functions common to VP8 and VP9
*/
#ifndef AVCODEC_VP89_RAC_H
#define AVCODEC_VP89_RAC_H
#include <stdint.h>
#include "libavutil/attributes.h"
#include "vpx_rac.h"
// rounding is different than vpx_rac_get, is vpx_rac_get wrong?
static av_always_inline int vp89_rac_get(VPXRangeCoder *c)
{
return vpx_rac_get_prob(c, 128);
}
static av_unused int vp89_rac_get_uint(VPXRangeCoder *c, int bits)
{
int value = 0;
while (bits--) {
value = (value << 1) | vp89_rac_get(c);
}
return value;
}
// how probabilities are associated with decisions is different I think
// well, the new scheme fits in the old but this way has one fewer branches per decision
static av_always_inline int vp89_rac_get_tree(VPXRangeCoder *c, const int8_t (*tree)[2],
const uint8_t *probs)
{
int i = 0;
do {
i = tree[i][vpx_rac_get_prob(c, probs[i])];
} while (i > 0);
return -i;
}
#endif /* AVCODEC_VP89_RAC_H */