--- /dev/null
+/*
+ * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
+ * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/**
+ * @file cabac.h
+ * Context Adaptive Binary Arithmetic Coder.
+ */
+
+
+#undef NDEBUG
+#include <assert.h>
+
+typedef struct CABACContext{
+ int low;
+ int range;
+ int outstanding_count;
+#ifdef STRICT_LIMITS
+ int symCount;
+#endif
+ uint8_t lps_range[2*64][4]; ///< rangeTabLPS
+ uint8_t lps_state[2*64]; ///< transIdxLPS
+ uint8_t mps_state[2*64]; ///< transIdxMPS
+ uint8_t *bytestream_start;
+ uint8_t *bytestream;
+ int bits_left; ///<
+ PutBitContext pb;
+}CABACContext;
+
+extern const uint8_t ff_h264_lps_range[64][4];
+extern const uint8_t ff_h264_mps_state[64];
+extern const uint8_t ff_h264_lps_state[64];
+
+void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
+void ff_init_cabac_decoder(CABACContext *c, uint8_t *buf, int buf_size);
+void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4],
+ uint8_t const *mps_state, uint8_t const *lps_state, int state_count);
+
+
+static inline void put_cabac_bit(CABACContext *c, int b){
+ put_bits(&c->pb, 1, b);
+ for(;c->outstanding_count; c->outstanding_count--){
+ put_bits(&c->pb, 1, 1-b);
+ }
+}
+
+static inline void renorm_cabac_encoder(CABACContext *c){
+ while(c->range < 0x100){
+ //FIXME optimize
+ if(c->low<0x100){
+ put_cabac_bit(c, 0);
+ }else if(c->low<0x200){
+ c->outstanding_count++;
+ c->low -= 0x100;
+ }else{
+ put_cabac_bit(c, 1);
+ c->low -= 0x200;
+ }
+
+ c->range+= c->range;
+ c->low += c->low;
+ }
+}
+
+static inline void put_cabac(CABACContext *c, uint8_t * const state, int bit){
+ int RangeLPS= c->lps_range[*state][((c->range)>>6)&3];
+
+ if(bit == ((*state)&1)){
+ c->range -= RangeLPS;
+ *state= c->mps_state[*state];
+ }else{
+ c->low += c->range - RangeLPS;
+ c->range = RangeLPS;
+ *state= c->lps_state[*state];
+ }
+
+ renorm_cabac_encoder(c);
+
+#ifdef STRICT_LIMITS
+ c->symCount++;
+#endif
+}
+
+static inline void put_cabac_static(CABACContext *c, int RangeLPS, int bit){
+ assert(c->range > RangeLPS);
+
+ if(!bit){
+ c->range -= RangeLPS;
+ }else{
+ c->low += c->range - RangeLPS;
+ c->range = RangeLPS;
+ }
+
+ renorm_cabac_encoder(c);
+
+#ifdef STRICT_LIMITS
+ c->symCount++;
+#endif
+}
+
+/**
+ * @param bit 0 -> write zero bit, !=0 write one bit
+ */
+static inline void put_cabac_bypass(CABACContext *c, int bit){
+ c->low += c->low;
+
+ if(bit){
+ c->low += c->range;
+ }
+//FIXME optimize
+ if(c->low<0x200){
+ put_cabac_bit(c, 0);
+ }else if(c->low<0x400){
+ c->outstanding_count++;
+ c->low -= 0x200;
+ }else{
+ put_cabac_bit(c, 1);
+ c->low -= 0x400;
+ }
+
+#ifdef STRICT_LIMITS
+ c->symCount++;
+#endif
+}
+
+/**
+ *
+ * @return the number of bytes written
+ */
+static inline int put_cabac_terminate(CABACContext *c, int bit){
+ c->range -= 2;
+
+ if(!bit){
+ renorm_cabac_encoder(c);
+ }else{
+ c->low += c->range;
+ c->range= 2;
+
+ renorm_cabac_encoder(c);
+
+ assert(c->low <= 0x1FF);
+ put_cabac_bit(c, c->low>>9);
+ put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
+
+ flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
+ }
+
+#ifdef STRICT_LIMITS
+ c->symCount++;
+#endif
+
+ return (get_bit_count(&c->pb)+7)>>3;
+}
+
+/**
+ * put (truncated) unary binarization.
+ */
+static inline void put_cabac_u(CABACContext *c, uint8_t * state, int v, int max, int max_index, int truncated){
+ int i;
+
+ assert(v <= max);
+
+#if 1
+ for(i=0; i<v; i++){
+ put_cabac(c, state, 1);
+ if(i < max_index) state++;
+ }
+ if(truncated==0 || v<max)
+ put_cabac(c, state, 0);
+#else
+ if(v <= max_index){
+ for(i=0; i<v; i++){
+ put_cabac(c, state+i, 1);
+ }
+ if(truncated==0 || v<max)
+ put_cabac(c, state+i, 0);
+ }else{
+ for(i=0; i<=max_index; i++){
+ put_cabac(c, state+i, 1);
+ }
+ for(; i<v; i++){
+ put_cabac(c, state+max_index, 1);
+ }
+ if(truncated==0 || v<max)
+ put_cabac(c, state+max_index, 0);
+ }
+#endif
+}
+
+/**
+ * put unary exp golomb k-th order binarization.
+ */
+static inline void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int max, int is_signed, int k, int max_index){
+ int i;
+
+ if(v==0)
+ put_cabac(c, state, 0);
+ else{
+ const int sign= v < 0;
+
+ if(is_signed) v= ABS(v);
+
+ if(v<max){
+ for(i=0; i<v; i++){
+ put_cabac(c, state, 1);
+ if(i < max_index) state++;
+ }
+
+ put_cabac(c, state, 0);
+ }else{
+ int m= 1<<k;
+
+ for(i=0; i<max; i++){
+ put_cabac(c, state, 1);
+ if(i < max_index) state++;
+ }
+
+ v -= max;
+ while(v >= m){ //FIXME optimize
+ put_cabac_bypass(c, 1);
+ v-= m;
+ m+= m;
+ }
+ put_cabac_bypass(c, 0);
+ while(m>>=1){
+ put_cabac_bypass(c, v&m);
+ }
+ }
+
+ if(is_signed)
+ put_cabac_bypass(c, sign);
+ }
+}
+
+static inline void renorm_cabac_decoder(CABACContext *c){
+ while(c->range < 0x10000){
+ c->range+= c->range;
+ c->low+= c->low;
+ if(--c->bits_left == 0){
+ c->low+= *c->bytestream++;
+ c->bits_left= 8;
+ }
+ }
+}
+
+static inline int get_cabac(CABACContext *c, uint8_t * const state){
+ int RangeLPS= c->lps_range[*state][((c->range)>>14)&3]<<8;
+ int bit;
+
+ c->range -= RangeLPS;
+ if(c->low < c->range){
+ bit= (*state)&1;
+ *state= c->mps_state[*state];
+ }else{
+ bit= ((*state)&1)^1;
+ c->low -= c->range;
+ c->range = RangeLPS;
+ *state= c->lps_state[*state];
+ }
+ renorm_cabac_decoder(c);
+
+ return bit;
+}
+
+static inline int get_cabac_static(CABACContext *c, int RangeLPS){
+ int bit;
+
+ c->range -= RangeLPS;
+ if(c->low < c->range){
+ bit= 0;
+ }else{
+ bit= 1;
+ c->low -= c->range;
+ c->range = RangeLPS;
+ }
+ renorm_cabac_decoder(c);
+
+ return bit;
+}
+
+static inline int get_cabac_bypass(CABACContext *c){
+ c->low += c->low;
+
+ if(--c->bits_left == 0){
+ c->low+= *c->bytestream++;
+ c->bits_left= 8;
+ }
+
+ if(c->low < c->range){
+ return 0;
+ }else{
+ c->low -= c->range;
+ return 1;
+ }
+}
+
+/**
+ *
+ * @return the number of bytes read or 0 if no end
+ */
+static inline int get_cabac_terminate(CABACContext *c){
+ c->range -= 2<<8;
+ if(c->low < c->range){
+ renorm_cabac_decoder(c);
+ return 0;
+ }else{
+ return c->bytestream - c->bytestream_start;
+ }
+}
+
+/**
+ * get (truncated) unnary binarization.
+ */
+static inline int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){
+ int i;
+
+ for(i=0; i<max; i++){
+ if(get_cabac(c, state)==0)
+ return i;
+
+ if(i< max_index) state++;
+ }
+
+ return truncated ? max : -1;
+}
+
+/**
+ * get unary exp golomb k-th order binarization.
+ */
+static inline int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signed, int k, int max_index){
+ int i, v;
+ int m= 1<<k;
+
+ if(get_cabac(c, state)==0)
+ return 0;
+
+ if(0 < max_index) state++;
+
+ for(i=1; i<max; i++){
+ if(get_cabac(c, state)==0){
+ if(is_signed && get_cabac_bypass(c)){
+ return -i;
+ }else
+ return i;
+ }
+
+ if(i < max_index) state++;
+ }
+
+ while(get_cabac_bypass(c)){
+ i+= m;
+ m+= m;
+ }
+
+ v=0;
+ while(m>>=1){
+ v+= v + get_cabac_bypass(c);
+ }
+ i += v;
+
+ if(is_signed && get_cabac_bypass(c)){
+ return -i;
+ }else
+ return i;
+}
projects / synfig.git / blobdiff