2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 * Context Adaptive Binary Arithmetic Coder.
30 typedef struct CABACContext{
33 int outstanding_count;
37 uint8_t lps_range[2*64][4]; ///< rangeTabLPS
38 uint8_t lps_state[2*64]; ///< transIdxLPS
39 uint8_t mps_state[2*64]; ///< transIdxMPS
45 const uint8_t ff_h264_lps_range[64][4];
46 const uint8_t ff_h264_mps_state[64];
47 const uint8_t ff_h264_lps_state[64];
49 void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
50 void ff_init_cabac_decoder(CABACContext *c, uint8_t *buf, int buf_size);
51 void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4],
52 uint8_t const *mps_state, uint8_t const *lps_state, int state_count);
55 static inline void put_cabac_bit(CABACContext *c, int b){
56 put_bits(&c->pb, 1, b);
57 for(;c->outstanding_count; c->outstanding_count--){
58 put_bits(&c->pb, 1, 1-b);
62 static inline void renorm_cabac_encoder(CABACContext *c){
63 while(c->range < 0x100){
67 }else if(c->low<0x200){
68 c->outstanding_count++;
80 static inline void put_cabac(CABACContext *c, uint8_t * const state, int bit){
81 int RangeLPS= c->lps_range[*state][((c->range)>>6)&3];
83 if(bit == ((*state)&1)){
85 *state= c->mps_state[*state];
87 c->low += c->range - RangeLPS;
89 *state= c->lps_state[*state];
92 renorm_cabac_encoder(c);
99 static inline void put_cabac_static(CABACContext *c, int RangeLPS, int bit){
100 assert(c->range > RangeLPS);
103 c->range -= RangeLPS;
105 c->low += c->range - RangeLPS;
109 renorm_cabac_encoder(c);
117 * @param bit 0 -> write zero bit, !=0 write one bit
119 static inline void put_cabac_bypass(CABACContext *c, int bit){
128 }else if(c->low<0x400){
129 c->outstanding_count++;
141 static inline void put_cabac_terminate(CABACContext *c, int bit){
145 renorm_cabac_encoder(c);
150 renorm_cabac_encoder(c);
152 assert(c->low <= 0x1FF);
153 put_cabac_bit(c, c->low>>9);
154 put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
156 flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
165 * put (truncated) unary binarization.
167 static inline void put_cabac_u(CABACContext *c, uint8_t * state, int v, int max, int max_index, int truncated){
174 put_cabac(c, state, 1);
175 if(i < max_index) state++;
177 if(truncated==0 || v<max)
178 put_cabac(c, state, 0);
182 put_cabac(c, state+i, 1);
184 if(truncated==0 || v<max)
185 put_cabac(c, state+i, 0);
187 for(i=0; i<=max_index; i++){
188 put_cabac(c, state+i, 1);
191 put_cabac(c, state+max_index, 1);
193 if(truncated==0 || v<max)
194 put_cabac(c, state+max_index, 0);
200 * put unary exp golomb k-th order binarization.
202 static inline void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int sign, int max, int is_signed, int k, int max_index){
206 put_cabac(c, state, 0);
210 put_cabac(c, state, 1);
211 if(i < max_index) state++;
214 put_cabac(c, state, 0);
218 for(i=0; i<max; i++){
219 put_cabac(c, state, 1);
220 if(i < max_index) state++;
224 while(v >= m){ //FIXME optimize
225 put_cabac_bypass(c, 1);
229 put_cabac_bypass(c, 0);
231 put_cabac_bypass(c, v&m);
236 put_cabac_bypass(c, sign);
240 static inline void renorm_cabac_decoder(CABACContext *c){
241 while(c->range < 0x10000){
244 if(--c->bits_left == 0){
245 c->low+= *c->bytestream++;
251 static inline int get_cabac(CABACContext *c, uint8_t * const state){
252 int RangeLPS= c->lps_range[*state][((c->range)>>14)&3]<<8;
255 c->range -= RangeLPS;
256 if(c->low < c->range){
258 *state= c->mps_state[*state];
263 *state= c->lps_state[*state];
265 renorm_cabac_decoder(c);
270 static inline int get_cabac_static(CABACContext *c, int RangeLPS){
273 c->range -= RangeLPS;
274 if(c->low < c->range){
281 renorm_cabac_decoder(c);
286 static inline int get_cabac_bypass(CABACContext *c){
289 if(--c->bits_left == 0){
290 c->low+= *c->bytestream++;
294 if(c->low < c->range){
302 static inline int get_cabac_terminate(CABACContext *c){
304 if(c->low < c->range){
305 renorm_cabac_decoder(c);
313 * get (truncated) unnary binarization.
315 static inline int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){
318 for(i=0; i<max; i++){
319 if(get_cabac(c, state)==0)
322 if(i< max_index) state++;
325 return truncated ? max : -1;
329 * get unary exp golomb k-th order binarization.
331 static inline int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signed, int k, int max_index){
335 if(get_cabac(c, state)==0)
338 if(0 < max_index) state++;
340 for(i=1; i<max; i++){
341 if(get_cabac(c, state)==0){
342 if(is_signed && get_cabac_bypass(c)){
348 if(i < max_index) state++;
351 while(get_cabac_bypass(c)){
358 v+= v + get_cabac_bypass(c);
362 if(is_signed && get_cabac_bypass(c)){