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https://git.ffmpeg.org/ffmpeg.git
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282 lines
6.9 KiB
C
282 lines
6.9 KiB
C
/*
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* exp golomb vlc stuff
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/**
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* @file golomb.h
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* @brief
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* exp golomb vlc stuff
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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#define INVALID_VLC 0x80000000
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extern const uint8_t ff_golomb_vlc_len[512];
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extern const uint8_t ff_ue_golomb_vlc_code[512];
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extern const int8_t ff_se_golomb_vlc_code[512];
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extern const uint8_t ff_ue_golomb_len[256];
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extern const uint8_t ff_interleaved_golomb_vlc_len[256];
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extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
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extern const int8_t ff_interleaved_se_golomb_vlc_code[256];
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/**
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* read unsigned exp golomb code.
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*/
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static inline int get_ue_golomb(GetBitContext *gb){
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unsigned int buf;
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int log;
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OPEN_READER(re, gb);
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UPDATE_CACHE(re, gb);
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buf=GET_CACHE(re, gb);
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if(buf >= (1<<27)){
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buf >>= 32 - 9;
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LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
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CLOSE_READER(re, gb);
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return ff_ue_golomb_vlc_code[buf];
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}else{
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log= 2*av_log2(buf) - 31;
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buf>>= log;
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buf--;
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LAST_SKIP_BITS(re, gb, 32 - log);
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CLOSE_READER(re, gb);
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return buf;
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}
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}
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static inline int svq3_get_ue_golomb(GetBitContext *gb){
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uint32_t buf;
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int log;
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OPEN_READER(re, gb);
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UPDATE_CACHE(re, gb);
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buf=GET_CACHE(re, gb);
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if(buf&0xAA800000){
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buf >>= 32 - 8;
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LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
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CLOSE_READER(re, gb);
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return ff_interleaved_ue_golomb_vlc_code[buf];
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}else{
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buf|=1;
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if((buf & 0xAAAAAAAA) == 0)
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return INVALID_VLC;
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for(log=31; (buf & 0x80000000) == 0; log--){
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buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
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}
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LAST_SKIP_BITS(re, gb, 63 - 2*log);
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CLOSE_READER(re, gb);
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return ((buf << log) >> log) - 1;
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}
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}
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/**
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* read unsigned truncated exp golomb code.
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*/
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static inline int get_te0_golomb(GetBitContext *gb, int range){
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assert(range >= 1);
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if(range==1) return 0;
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else if(range==2) return get_bits1(gb)^1;
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else return get_ue_golomb(gb);
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}
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/**
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* read unsigned truncated exp golomb code.
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*/
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static inline int get_te_golomb(GetBitContext *gb, int range){
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assert(range >= 1);
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if(range==2) return get_bits1(gb)^1;
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else return get_ue_golomb(gb);
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}
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/**
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* read signed exp golomb code.
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*/
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static inline int get_se_golomb(GetBitContext *gb){
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unsigned int buf;
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int log;
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OPEN_READER(re, gb);
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UPDATE_CACHE(re, gb);
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buf=GET_CACHE(re, gb);
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if(buf >= (1<<27)){
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buf >>= 32 - 9;
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LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
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CLOSE_READER(re, gb);
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return ff_se_golomb_vlc_code[buf];
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}else{
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log= 2*av_log2(buf) - 31;
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buf>>= log;
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LAST_SKIP_BITS(re, gb, 32 - log);
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CLOSE_READER(re, gb);
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if(buf&1) buf= -(buf>>1);
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else buf= (buf>>1);
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return buf;
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}
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}
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static inline int svq3_get_se_golomb(GetBitContext *gb){
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unsigned int buf;
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int log;
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OPEN_READER(re, gb);
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UPDATE_CACHE(re, gb);
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buf=GET_CACHE(re, gb);
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if(buf&0xAA800000){
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buf >>= 32 - 8;
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LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
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CLOSE_READER(re, gb);
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return ff_interleaved_se_golomb_vlc_code[buf];
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}else{
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buf |=1;
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if((buf & 0xAAAAAAAA) == 0)
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return INVALID_VLC;
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for(log=31; (buf & 0x80000000) == 0; log--){
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buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
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}
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LAST_SKIP_BITS(re, gb, 63 - 2*log);
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CLOSE_READER(re, gb);
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return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
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}
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}
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#ifdef TRACE
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static inline int get_ue(GetBitContext *s, char *file, char *func, int line){
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int show= show_bits(s, 24);
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int pos= get_bits_count(s);
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int i= get_ue_golomb(s);
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int len= get_bits_count(s) - pos;
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int bits= show>>(24-len);
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print_bin(bits, len);
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printf("%5d %2d %3d ue @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
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return i;
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}
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static inline int get_se(GetBitContext *s, char *file, char *func, int line){
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int show= show_bits(s, 24);
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int pos= get_bits_count(s);
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int i= get_se_golomb(s);
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int len= get_bits_count(s) - pos;
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int bits= show>>(24-len);
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print_bin(bits, len);
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printf("%5d %2d %3d se @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
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return i;
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}
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static inline int get_te(GetBitContext *s, int r, char *file, char *func, int line){
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int show= show_bits(s, 24);
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int pos= get_bits_count(s);
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int i= get_te0_golomb(s, r);
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int len= get_bits_count(s) - pos;
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int bits= show>>(24-len);
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print_bin(bits, len);
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printf("%5d %2d %3d te @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
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return i;
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}
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#define get_ue_golomb(a) get_ue(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
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#define get_se_golomb(a) get_se(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
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#define get_te_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
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#define get_te0_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
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#endif
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/**
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* write unsigned exp golomb code.
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*/
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static inline void set_ue_golomb(PutBitContext *pb, int i){
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int e;
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assert(i>=0);
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#if 0
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if(i=0){
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put_bits(pb, 1, 1);
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return;
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}
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#endif
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if(i<256)
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put_bits(pb, ff_ue_golomb_len[i], i+1);
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else{
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e= av_log2(i+1);
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put_bits(pb, 2*e+1, i+1);
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}
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}
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/**
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* write truncated unsigned exp golomb code.
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*/
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static inline void set_te_golomb(PutBitContext *pb, int i, int range){
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assert(range >= 1);
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assert(i<=range);
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if(range==2) put_bits(pb, 1, i^1);
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else set_ue_golomb(pb, i);
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}
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/**
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* write signed exp golomb code.
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*/
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static inline void set_se_golomb(PutBitContext *pb, int i){
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#if 0
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if(i<=0) i= -2*i;
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else i= 2*i-1;
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#elif 1
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i= 2*i-1;
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if(i<0) i^= -1; //FIXME check if gcc does the right thing
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#else
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i= 2*i-1;
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i^= (i>>31);
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#endif
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set_ue_golomb(pb, i);
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}
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