mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-28 20:53:54 +02:00
14e9ffc1e4
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: Ronald S. Bultje <rsbultje@gmail.com>
165 lines
4.3 KiB
C
165 lines
4.3 KiB
C
/*
|
|
* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
|
|
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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.
|
|
*
|
|
* Libav 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 Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* Context Adaptive Binary Arithmetic Coder inline functions
|
|
*/
|
|
|
|
#ifndef AVCODEC_CABAC_FUNCTIONS_H
|
|
#define AVCODEC_CABAC_FUNCTIONS_H
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "cabac.h"
|
|
#include "config.h"
|
|
|
|
#if ARCH_X86
|
|
# include "x86/cabac.h"
|
|
#endif
|
|
|
|
extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
|
|
static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
|
|
static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
|
|
static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
|
|
static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
|
|
|
|
static void refill(CABACContext *c){
|
|
#if CABAC_BITS == 16
|
|
c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
|
|
#else
|
|
c->low+= c->bytestream[0]<<1;
|
|
#endif
|
|
c->low -= CABAC_MASK;
|
|
if (c->bytestream < c->bytestream_end)
|
|
c->bytestream += CABAC_BITS / 8;
|
|
}
|
|
|
|
static inline void renorm_cabac_decoder_once(CABACContext *c){
|
|
int shift= (uint32_t)(c->range - 0x100)>>31;
|
|
c->range<<= shift;
|
|
c->low <<= shift;
|
|
if(!(c->low & CABAC_MASK))
|
|
refill(c);
|
|
}
|
|
|
|
#ifndef get_cabac_inline
|
|
static void refill2(CABACContext *c){
|
|
int i, x;
|
|
|
|
x= c->low ^ (c->low-1);
|
|
i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
|
|
|
|
x= -CABAC_MASK;
|
|
|
|
#if CABAC_BITS == 16
|
|
x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
|
|
#else
|
|
x+= c->bytestream[0]<<1;
|
|
#endif
|
|
|
|
c->low += x<<i;
|
|
if (c->bytestream < c->bytestream_end)
|
|
c->bytestream += CABAC_BITS/8;
|
|
}
|
|
|
|
static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
|
|
int s = *state;
|
|
int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
|
|
int bit, lps_mask;
|
|
|
|
c->range -= RangeLPS;
|
|
lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
|
|
|
|
c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
|
|
c->range += (RangeLPS - c->range) & lps_mask;
|
|
|
|
s^=lps_mask;
|
|
*state= (ff_h264_mlps_state+128)[s];
|
|
bit= s&1;
|
|
|
|
lps_mask= ff_h264_norm_shift[c->range];
|
|
c->range<<= lps_mask;
|
|
c->low <<= lps_mask;
|
|
if(!(c->low & CABAC_MASK))
|
|
refill2(c);
|
|
return bit;
|
|
}
|
|
#endif
|
|
|
|
static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
|
|
return get_cabac_inline(c,state);
|
|
}
|
|
|
|
static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
|
|
return get_cabac_inline(c,state);
|
|
}
|
|
|
|
static int av_unused get_cabac_bypass(CABACContext *c){
|
|
int range;
|
|
c->low += c->low;
|
|
|
|
if(!(c->low & CABAC_MASK))
|
|
refill(c);
|
|
|
|
range= c->range<<(CABAC_BITS+1);
|
|
if(c->low < range){
|
|
return 0;
|
|
}else{
|
|
c->low -= range;
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
|
|
#ifndef get_cabac_bypass_sign
|
|
static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
|
|
int range, mask;
|
|
c->low += c->low;
|
|
|
|
if(!(c->low & CABAC_MASK))
|
|
refill(c);
|
|
|
|
range= c->range<<(CABAC_BITS+1);
|
|
c->low -= range;
|
|
mask= c->low >> 31;
|
|
range &= mask;
|
|
c->low += range;
|
|
return (val^mask)-mask;
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
*
|
|
* @return the number of bytes read or 0 if no end
|
|
*/
|
|
static int av_unused get_cabac_terminate(CABACContext *c){
|
|
c->range -= 2;
|
|
if(c->low < c->range<<(CABAC_BITS+1)){
|
|
renorm_cabac_decoder_once(c);
|
|
return 0;
|
|
}else{
|
|
return c->bytestream - c->bytestream_start;
|
|
}
|
|
}
|
|
|
|
#endif /* AVCODEC_CABAC_FUNCTIONS_H */
|