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00027 #include <string.h>
00028
00029 #include "libavutil/common.h"
00030 #include "get_bits.h"
00031 #include "cabac.h"
00032 #include "cabac_functions.h"
00033
00034 static const uint8_t lps_range[64][4]= {
00035 {128,176,208,240}, {128,167,197,227}, {128,158,187,216}, {123,150,178,205},
00036 {116,142,169,195}, {111,135,160,185}, {105,128,152,175}, {100,122,144,166},
00037 { 95,116,137,158}, { 90,110,130,150}, { 85,104,123,142}, { 81, 99,117,135},
00038 { 77, 94,111,128}, { 73, 89,105,122}, { 69, 85,100,116}, { 66, 80, 95,110},
00039 { 62, 76, 90,104}, { 59, 72, 86, 99}, { 56, 69, 81, 94}, { 53, 65, 77, 89},
00040 { 51, 62, 73, 85}, { 48, 59, 69, 80}, { 46, 56, 66, 76}, { 43, 53, 63, 72},
00041 { 41, 50, 59, 69}, { 39, 48, 56, 65}, { 37, 45, 54, 62}, { 35, 43, 51, 59},
00042 { 33, 41, 48, 56}, { 32, 39, 46, 53}, { 30, 37, 43, 50}, { 29, 35, 41, 48},
00043 { 27, 33, 39, 45}, { 26, 31, 37, 43}, { 24, 30, 35, 41}, { 23, 28, 33, 39},
00044 { 22, 27, 32, 37}, { 21, 26, 30, 35}, { 20, 24, 29, 33}, { 19, 23, 27, 31},
00045 { 18, 22, 26, 30}, { 17, 21, 25, 28}, { 16, 20, 23, 27}, { 15, 19, 22, 25},
00046 { 14, 18, 21, 24}, { 14, 17, 20, 23}, { 13, 16, 19, 22}, { 12, 15, 18, 21},
00047 { 12, 14, 17, 20}, { 11, 14, 16, 19}, { 11, 13, 15, 18}, { 10, 12, 15, 17},
00048 { 10, 12, 14, 16}, { 9, 11, 13, 15}, { 9, 11, 12, 14}, { 8, 10, 12, 14},
00049 { 8, 9, 11, 13}, { 7, 9, 11, 12}, { 7, 9, 10, 12}, { 7, 8, 10, 11},
00050 { 6, 8, 9, 11}, { 6, 7, 9, 10}, { 6, 7, 8, 9}, { 2, 2, 2, 2},
00051 };
00052
00053 uint8_t ff_h264_mlps_state[4*64];
00054 uint8_t ff_h264_lps_range[4*2*64];
00055 static uint8_t h264_mps_state[2 * 64];
00056
00057 static const uint8_t mps_state[64]= {
00058 1, 2, 3, 4, 5, 6, 7, 8,
00059 9,10,11,12,13,14,15,16,
00060 17,18,19,20,21,22,23,24,
00061 25,26,27,28,29,30,31,32,
00062 33,34,35,36,37,38,39,40,
00063 41,42,43,44,45,46,47,48,
00064 49,50,51,52,53,54,55,56,
00065 57,58,59,60,61,62,62,63,
00066 };
00067
00068 static const uint8_t lps_state[64]= {
00069 0, 0, 1, 2, 2, 4, 4, 5,
00070 6, 7, 8, 9, 9,11,11,12,
00071 13,13,15,15,16,16,18,18,
00072 19,19,21,21,22,22,23,24,
00073 24,25,26,26,27,27,28,29,
00074 29,30,30,30,31,32,32,33,
00075 33,33,34,34,35,35,35,36,
00076 36,36,37,37,37,38,38,63,
00077 };
00078
00079 const uint8_t ff_h264_norm_shift[512]= {
00080 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
00081 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
00082 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
00083 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
00084 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
00085 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
00086 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
00087 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
00088 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
00089 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
00090 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
00091 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
00092 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00093 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00094 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00095 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00096 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00097 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00098 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00099 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
00100 };
00101
00106 void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
00107 init_put_bits(&c->pb, buf, buf_size);
00108
00109 c->low= 0;
00110 c->range= 0x1FE;
00111 c->outstanding_count= 0;
00112 c->pb.bit_left++;
00113 }
00114
00119 void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
00120 c->bytestream_start=
00121 c->bytestream= buf;
00122 c->bytestream_end= buf + buf_size;
00123
00124 #if CABAC_BITS == 16
00125 c->low = (*c->bytestream++)<<18;
00126 c->low+= (*c->bytestream++)<<10;
00127 #else
00128 c->low = (*c->bytestream++)<<10;
00129 #endif
00130 c->low+= ((*c->bytestream++)<<2) + 2;
00131 c->range= 0x1FE;
00132 }
00133
00134 void ff_init_cabac_states(CABACContext *c){
00135 int i, j;
00136
00137 for(i=0; i<64; i++){
00138 for(j=0; j<4; j++){
00139 ff_h264_lps_range[j*2*64+2*i+0]=
00140 ff_h264_lps_range[j*2*64+2*i+1]= lps_range[i][j];
00141 }
00142
00143 ff_h264_mlps_state[128+2*i+0]=
00144 h264_mps_state[2 * i + 0] = 2 * mps_state[i] + 0;
00145 ff_h264_mlps_state[128+2*i+1]=
00146 h264_mps_state[2 * i + 1] = 2 * mps_state[i] + 1;
00147
00148 if( i ){
00149 ff_h264_mlps_state[128-2*i-1]= 2*lps_state[i]+0;
00150 ff_h264_mlps_state[128-2*i-2]= 2*lps_state[i]+1;
00151 }else{
00152 ff_h264_mlps_state[128-2*i-1]= 1;
00153 ff_h264_mlps_state[128-2*i-2]= 0;
00154 }
00155 }
00156 }
00157
00158 #ifdef TEST
00159 #define SIZE 10240
00160
00161 #include "libavutil/lfg.h"
00162 #include "avcodec.h"
00163 #include "cabac.h"
00164
00165 static inline void put_cabac_bit(CABACContext *c, int b){
00166 put_bits(&c->pb, 1, b);
00167 for(;c->outstanding_count; c->outstanding_count--){
00168 put_bits(&c->pb, 1, 1-b);
00169 }
00170 }
00171
00172 static inline void renorm_cabac_encoder(CABACContext *c){
00173 while(c->range < 0x100){
00174
00175 if(c->low<0x100){
00176 put_cabac_bit(c, 0);
00177 }else if(c->low<0x200){
00178 c->outstanding_count++;
00179 c->low -= 0x100;
00180 }else{
00181 put_cabac_bit(c, 1);
00182 c->low -= 0x200;
00183 }
00184
00185 c->range+= c->range;
00186 c->low += c->low;
00187 }
00188 }
00189
00190 static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
00191 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
00192
00193 if(bit == ((*state)&1)){
00194 c->range -= RangeLPS;
00195 *state = h264_mps_state[*state];
00196 }else{
00197 c->low += c->range - RangeLPS;
00198 c->range = RangeLPS;
00199 }
00200
00201 renorm_cabac_encoder(c);
00202 }
00203
00207 static void put_cabac_bypass(CABACContext *c, int bit){
00208 c->low += c->low;
00209
00210 if(bit){
00211 c->low += c->range;
00212 }
00213
00214 if(c->low<0x200){
00215 put_cabac_bit(c, 0);
00216 }else if(c->low<0x400){
00217 c->outstanding_count++;
00218 c->low -= 0x200;
00219 }else{
00220 put_cabac_bit(c, 1);
00221 c->low -= 0x400;
00222 }
00223 }
00224
00229 static int put_cabac_terminate(CABACContext *c, int bit){
00230 c->range -= 2;
00231
00232 if(!bit){
00233 renorm_cabac_encoder(c);
00234 }else{
00235 c->low += c->range;
00236 c->range= 2;
00237
00238 renorm_cabac_encoder(c);
00239
00240 assert(c->low <= 0x1FF);
00241 put_cabac_bit(c, c->low>>9);
00242 put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
00243
00244 flush_put_bits(&c->pb);
00245 }
00246
00247 return (put_bits_count(&c->pb)+7)>>3;
00248 }
00249
00250 int main(void){
00251 CABACContext c;
00252 uint8_t b[9*SIZE];
00253 uint8_t r[9*SIZE];
00254 int i;
00255 uint8_t state[10]= {0};
00256 AVLFG prng;
00257
00258 av_lfg_init(&prng, 1);
00259 ff_init_cabac_encoder(&c, b, SIZE);
00260 ff_init_cabac_states(&c);
00261
00262 for(i=0; i<SIZE; i++){
00263 r[i] = av_lfg_get(&prng) % 7;
00264 }
00265
00266 for(i=0; i<SIZE; i++){
00267 START_TIMER
00268 put_cabac_bypass(&c, r[i]&1);
00269 STOP_TIMER("put_cabac_bypass")
00270 }
00271
00272 for(i=0; i<SIZE; i++){
00273 START_TIMER
00274 put_cabac(&c, state, r[i]&1);
00275 STOP_TIMER("put_cabac")
00276 }
00277
00278 put_cabac_terminate(&c, 1);
00279
00280 ff_init_cabac_decoder(&c, b, SIZE);
00281
00282 memset(state, 0, sizeof(state));
00283
00284 for(i=0; i<SIZE; i++){
00285 START_TIMER
00286 if( (r[i]&1) != get_cabac_bypass(&c) )
00287 av_log(NULL, AV_LOG_ERROR, "CABAC bypass failure at %d\n", i);
00288 STOP_TIMER("get_cabac_bypass")
00289 }
00290
00291 for(i=0; i<SIZE; i++){
00292 START_TIMER
00293 if( (r[i]&1) != get_cabac(&c, state) )
00294 av_log(NULL, AV_LOG_ERROR, "CABAC failure at %d\n", i);
00295 STOP_TIMER("get_cabac")
00296 }
00297 if(!get_cabac_terminate(&c))
00298 av_log(NULL, AV_LOG_ERROR, "where's the Terminator?\n");
00299
00300 return 0;
00301 }
00302
00303 #endif