2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of Libav.
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * Context Adaptive Binary Arithmetic Coder inline functions
27 #ifndef AVCODEC_CABAC_FUNCTIONS_H
28 #define AVCODEC_CABAC_FUNCTIONS_H
36 # include "x86/cabac.h"
39 extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
40 static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
41 static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
42 static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
43 static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
45 static void refill(CABACContext *c){
47 c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
49 c->low+= c->bytestream[0]<<1;
52 if (c->bytestream < c->bytestream_end)
53 c->bytestream += CABAC_BITS / 8;
56 static inline void renorm_cabac_decoder_once(CABACContext *c){
57 int shift= (uint32_t)(c->range - 0x100)>>31;
60 if(!(c->low & CABAC_MASK))
64 #ifndef get_cabac_inline
65 static void refill2(CABACContext *c){
68 x= c->low ^ (c->low-1);
69 i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
74 x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
76 x+= c->bytestream[0]<<1;
80 if (c->bytestream < c->bytestream_end)
81 c->bytestream += CABAC_BITS/8;
84 static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
86 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
90 lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
92 c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
93 c->range += (RangeLPS - c->range) & lps_mask;
96 *state= (ff_h264_mlps_state+128)[s];
99 lps_mask= ff_h264_norm_shift[c->range];
100 c->range<<= lps_mask;
102 if(!(c->low & CABAC_MASK))
108 static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
109 return get_cabac_inline(c,state);
112 static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
113 return get_cabac_inline(c,state);
116 static int av_unused get_cabac_bypass(CABACContext *c){
120 if(!(c->low & CABAC_MASK))
123 range= c->range<<(CABAC_BITS+1);
133 #ifndef get_cabac_bypass_sign
134 static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
138 if(!(c->low & CABAC_MASK))
141 range= c->range<<(CABAC_BITS+1);
146 return (val^mask)-mask;
152 * @return the number of bytes read or 0 if no end
154 static int av_unused get_cabac_terminate(CABACContext *c){
156 if(c->low < c->range<<(CABAC_BITS+1)){
157 renorm_cabac_decoder_once(c);
160 return c->bytestream - c->bytestream_start;
164 #endif /* AVCODEC_CABAC_FUNCTIONS_H */