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7f668cd2b5
The reason is this is easier for PIC code (in particular on darwin...). Keep the old names as pointers (static in cabac_functions.h so gcc knows these are just immediate offsets) so the c code can nicely stay the same (alternatively could use offsets directly in the functions needing the tables). This should produce the same code as before with non-pic and better code (confirmed) with pic. The assembly uses the new table but still won't work for PIC case. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
163 lines
4.2 KiB
C
163 lines
4.2 KiB
C
/*
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* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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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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* Context Adaptive Binary Arithmetic Coder inline functions
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*/
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#ifndef AVCODEC_CABAC_FUNCTIONS_H
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#define AVCODEC_CABAC_FUNCTIONS_H
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#include <stdint.h>
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#include "cabac.h"
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#include "config.h"
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#if ARCH_X86
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# include "x86/cabac.h"
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#endif
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extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
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static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
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static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
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static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
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static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
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static void refill(CABACContext *c){
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#if CABAC_BITS == 16
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c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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#else
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c->low+= c->bytestream[0]<<1;
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#endif
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c->low -= CABAC_MASK;
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c->bytestream += CABAC_BITS / 8;
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}
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static inline void renorm_cabac_decoder_once(CABACContext *c){
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int shift= (uint32_t)(c->range - 0x100)>>31;
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c->range<<= shift;
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c->low <<= shift;
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if(!(c->low & CABAC_MASK))
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refill(c);
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}
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#ifndef get_cabac_inline
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static void refill2(CABACContext *c){
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int i, x;
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x= c->low ^ (c->low-1);
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i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
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x= -CABAC_MASK;
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#if CABAC_BITS == 16
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x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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#else
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x+= c->bytestream[0]<<1;
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#endif
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c->low += x<<i;
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c->bytestream += CABAC_BITS/8;
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}
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static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
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int s = *state;
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int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
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int bit, lps_mask;
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c->range -= RangeLPS;
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lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
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c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
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c->range += (RangeLPS - c->range) & lps_mask;
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s^=lps_mask;
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*state= (ff_h264_mlps_state+128)[s];
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bit= s&1;
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lps_mask= ff_h264_norm_shift[c->range];
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c->range<<= lps_mask;
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c->low <<= lps_mask;
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if(!(c->low & CABAC_MASK))
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refill2(c);
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return bit;
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}
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#endif
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static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
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return get_cabac_inline(c,state);
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}
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static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
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return get_cabac_inline(c,state);
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}
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static int av_unused get_cabac_bypass(CABACContext *c){
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int range;
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c->low += c->low;
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if(!(c->low & CABAC_MASK))
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refill(c);
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range= c->range<<(CABAC_BITS+1);
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if(c->low < range){
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return 0;
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}else{
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c->low -= range;
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return 1;
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}
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}
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#ifndef get_cabac_bypass_sign
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static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
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int range, mask;
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c->low += c->low;
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if(!(c->low & CABAC_MASK))
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refill(c);
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range= c->range<<(CABAC_BITS+1);
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c->low -= range;
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mask= c->low >> 31;
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range &= mask;
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c->low += range;
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return (val^mask)-mask;
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}
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#endif
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/**
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*
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* @return the number of bytes read or 0 if no end
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*/
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static int av_unused get_cabac_terminate(CABACContext *c){
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c->range -= 2;
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if(c->low < c->range<<(CABAC_BITS+1)){
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renorm_cabac_decoder_once(c);
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return 0;
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}else{
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return c->bytestream - c->bytestream_start;
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}
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}
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#endif /* AVCODEC_CABAC_FUNCTIONS_H */
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