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* H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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* This file is part of FFmpeg.
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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* Context Adaptive Binary Arithmetic Coder.
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#ifndef AVCODEC_CABAC_H
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#define AVCODEC_CABAC_H
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#include "libavutil/x86_cpu.h"
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#define CABAC_MASK ((1<<CABAC_BITS)-1)
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#define BRANCHLESS_CABAC_DECODER 1
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//#define ARCH_X86_DISABLED 1
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typedef struct CABACContext{
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int outstanding_count;
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const uint8_t *bytestream_start;
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const uint8_t *bytestream;
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const uint8_t *bytestream_end;
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extern uint8_t ff_h264_mlps_state[4*64];
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extern uint8_t ff_h264_lps_range[4*2*64]; ///< rangeTabLPS
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extern uint8_t ff_h264_mps_state[2*64]; ///< transIdxMPS
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extern uint8_t ff_h264_lps_state[2*64]; ///< transIdxLPS
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extern const uint8_t ff_h264_norm_shift[512];
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void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
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void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size);
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void ff_init_cabac_states(CABACContext *c);
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static inline void put_cabac_bit(CABACContext *c, int b){
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put_bits(&c->pb, 1, b);
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for(;c->outstanding_count; c->outstanding_count--){
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put_bits(&c->pb, 1, 1-b);
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static inline void renorm_cabac_encoder(CABACContext *c){
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while(c->range < 0x100){
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}else if(c->low<0x200){
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c->outstanding_count++;
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static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
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int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
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if(bit == ((*state)&1)){
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*state= ff_h264_mps_state[*state];
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c->low += c->range - RangeLPS;
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*state= ff_h264_lps_state[*state];
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renorm_cabac_encoder(c);
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static void put_cabac_static(CABACContext *c, int RangeLPS, int bit){
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assert(c->range > RangeLPS);
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c->range -= RangeLPS;
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c->low += c->range - RangeLPS;
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renorm_cabac_encoder(c);
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* @param bit 0 -> write zero bit, !=0 write one bit
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static void put_cabac_bypass(CABACContext *c, int bit){
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}else if(c->low<0x400){
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c->outstanding_count++;
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* @return the number of bytes written
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static int put_cabac_terminate(CABACContext *c, int bit){
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renorm_cabac_encoder(c);
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renorm_cabac_encoder(c);
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assert(c->low <= 0x1FF);
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put_cabac_bit(c, c->low>>9);
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put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
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flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
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return (put_bits_count(&c->pb)+7)>>3;
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* put (truncated) unary binarization.
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static void put_cabac_u(CABACContext *c, uint8_t * state, int v, int max, int max_index, int truncated){
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put_cabac(c, state, 1);
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if(i < max_index) state++;
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if(truncated==0 || v<max)
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put_cabac(c, state, 0);
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put_cabac(c, state+i, 1);
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if(truncated==0 || v<max)
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put_cabac(c, state+i, 0);
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for(i=0; i<=max_index; i++){
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put_cabac(c, state+i, 1);
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put_cabac(c, state+max_index, 1);
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if(truncated==0 || v<max)
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put_cabac(c, state+max_index, 0);
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* put unary exp golomb k-th order binarization.
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static void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int max, int is_signed, int k, int max_index){
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put_cabac(c, state, 0);
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const int sign= v < 0;
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if(is_signed) v= FFABS(v);
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put_cabac(c, state, 1);
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if(i < max_index) state++;
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put_cabac(c, state, 0);
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for(i=0; i<max; i++){
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put_cabac(c, state, 1);
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if(i < max_index) state++;
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while(v >= m){ //FIXME optimize
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put_cabac_bypass(c, 1);
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put_cabac_bypass(c, 0);
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put_cabac_bypass(c, v&m);
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put_cabac_bypass(c, sign);
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static void refill(CABACContext *c){
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c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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c->low+= c->bytestream[0]<<1;
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c->low -= CABAC_MASK;
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c->bytestream+= CABAC_BITS/8;
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#if ! ( ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) )
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static void refill2(CABACContext *c){
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x= c->low ^ (c->low-1);
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i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
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x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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x+= c->bytestream[0]<<1;
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c->bytestream+= CABAC_BITS/8;
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static inline void renorm_cabac_decoder(CABACContext *c){
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while(c->range < 0x100){
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if(!(c->low & CABAC_MASK))
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static inline void renorm_cabac_decoder_once(CABACContext *c){
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#ifdef ARCH_X86_DISABLED
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"lea -0x100(%0), %2 \n\t"
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"shr $31, %2 \n\t" //FIXME 31->63 for x86-64
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: "+r"(c->range), "+r"(c->low), "+c"(temp)
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"cmp $0x100, %0 \n\t"
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"setb %%cl \n\t" //FIXME 31->63 for x86-64
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: "+r"(c->range), "+r"(c->low), "+c"(temp)
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"lea -0x100(%0), %%eax \n\t"
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: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
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"cmp $0x100, %0 \n\t"
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"sbb %%edx, %%edx \n\t"
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: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
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"cmp $0x100, %0 \n\t"
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"lea (%0, %0), %%eax \n\t"
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"lea (%1, %1), %%edx \n\t"
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"cmovb %%eax, %0 \n\t"
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"cmovb %%edx, %1 \n\t"
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: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
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int shift= (uint32_t)(c->range - 0x100)>>31;
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if(!(c->low & CABAC_MASK))
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static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
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//FIXME gcc generates duplicate load/stores for c->low and c->range
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#define BYTESTART "16"
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#define BYTESTART "12"
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#if ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS)
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#ifndef BRANCHLESS_CABAC_DECODER
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"movzbl (%1), %0 \n\t"
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"movl "RANGE "(%2), %%ebx \n\t"
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"movl "RANGE "(%2), %%edx \n\t"
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"andl $0xC0, %%ebx \n\t"
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"movzbl "MANGLE(ff_h264_lps_range)"(%0, %%ebx, 2), %%esi\n\t"
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"movl "LOW "(%2), %%ebx \n\t"
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//eax:state ebx:low, edx:range, esi:RangeLPS
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"subl %%esi, %%edx \n\t"
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"movl %%edx, %%ecx \n\t"
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"shll $17, %%ecx \n\t"
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"cmpl %%ecx, %%ebx \n\t"
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//athlon:4067 P3:4110
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"lea -0x100(%%edx), %%ecx \n\t"
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"shr $31, %%ecx \n\t"
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"shl %%cl, %%edx \n\t"
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"shl %%cl, %%ebx \n\t"
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//athlon:4057 P3:4130
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"cmp $0x100, %%edx \n\t" //FIXME avoidable
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"shl %%cl, %%edx \n\t"
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"shl %%cl, %%ebx \n\t"
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"movzbl "MANGLE(ff_h264_mps_state)"(%0), %%ecx \n\t"
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"movb %%cl, (%1) \n\t"
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//eax:state ebx:low, edx:range, esi:RangeLPS
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"test %%bx, %%bx \n\t"
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"mov "BYTE "(%2), %%"REG_S" \n\t"
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"subl $0xFFFF, %%ebx \n\t"
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"movzwl (%%"REG_S"), %%ecx \n\t"
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"shrl $15, %%ecx \n\t"
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"add $2, %%"REG_S" \n\t"
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"addl %%ecx, %%ebx \n\t"
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"mov %%"REG_S", "BYTE "(%2) \n\t"
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//eax:state ebx:low, edx:range, esi:RangeLPS
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"subl %%ecx, %%ebx \n\t"
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"movl %%esi, %%edx \n\t"
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"movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx \n\t"
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"shll %%cl, %%ebx \n\t"
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"shll %%cl, %%edx \n\t"
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"movzbl "MANGLE(ff_h264_lps_state)"(%0), %%ecx \n\t"
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"movb %%cl, (%1) \n\t"
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"test %%bx, %%bx \n\t"
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"mov "BYTE "(%2), %%"REG_c" \n\t"
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"movzwl (%%"REG_c"), %%esi \n\t"
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"shrl $15, %%esi \n\t"
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"subl $0xFFFF, %%esi \n\t"
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"add $2, %%"REG_c" \n\t"
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"mov %%"REG_c", "BYTE "(%2) \n\t"
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"leal -1(%%ebx), %%ecx \n\t"
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"xorl %%ebx, %%ecx \n\t"
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"shrl $15, %%ecx \n\t"
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"movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"
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"shll %%cl , %%esi \n\t"
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"addl %%esi, %%ebx \n\t"
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"movl %%edx, "RANGE "(%2) \n\t"
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"movl %%ebx, "LOW "(%2) \n\t"
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:"=&a"(bit) //FIXME this is fragile gcc either runs out of registers or miscompiles it (for example if "+a"(bit) or "+m"(*state) is used
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: "%"REG_c, "%ebx", "%edx", "%"REG_S, "memory"
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#else /* BRANCHLESS_CABAC_DECODER */
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
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"mov "tmp" , %%ecx \n\t"\
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"shl $17 , "tmp" \n\t"\
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"cmp "low" , "tmp" \n\t"\
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"cmova %%ecx , "range" \n\t"\
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"sbb %%ecx , %%ecx \n\t"\
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"and %%ecx , "tmp" \n\t"\
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"sub "tmp" , "low" \n\t"\
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"xor %%ecx , "ret" \n\t"
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#else /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
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"mov "tmp" , %%ecx \n\t"\
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"shl $17 , "tmp" \n\t"\
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"sub "low" , "tmp" \n\t"\
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"sar $31 , "tmp" \n\t" /*lps_mask*/\
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"sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
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"and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
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"add %%ecx , "range" \n\t" /*new range*/\
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"shl $17 , %%ecx \n\t"\
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"and "tmp" , %%ecx \n\t"\
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"sub %%ecx , "low" \n\t"\
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"xor "tmp" , "ret" \n\t"
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#endif /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
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"movzbl "statep" , "ret" \n\t"\
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"mov "range" , "tmp" \n\t"\
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"and $0xC0 , "range" \n\t"\
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"movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\
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"sub "range" , "tmp" \n\t"\
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BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
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"movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx \n\t"\
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"shl %%cl , "range" \n\t"\
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"movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp" \n\t"\
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"mov "tmpbyte" , "statep" \n\t"\
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"shl %%cl , "low" \n\t"\
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"test "lowword" , "lowword" \n\t"\
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"mov "BYTE"("cabac"), %%"REG_c" \n\t"\
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"movzwl (%%"REG_c") , "tmp" \n\t"\
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"shr $15 , "tmp" \n\t"\
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"sub $0xFFFF , "tmp" \n\t"\
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"add $2 , %%"REG_c" \n\t"\
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"mov %%"REG_c" , "BYTE "("cabac") \n\t"\
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"lea -1("low") , %%ecx \n\t"\
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"xor "low" , %%ecx \n\t"\
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"shr $15 , %%ecx \n\t"\
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"movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"\
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"add $7 , %%ecx \n\t"\
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"shl %%cl , "tmp" \n\t"\
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"add "tmp" , "low" \n\t"\
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"movl "RANGE "(%2), %%esi \n\t"
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"movl "LOW "(%2), %%ebx \n\t"
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BRANCHLESS_GET_CABAC("%0", "%2", "(%1)", "%%ebx", "%%bx", "%%esi", "%%edx", "%%dl")
531
"movl %%esi, "RANGE "(%2) \n\t"
532
"movl %%ebx, "LOW "(%2) \n\t"
536
: "%"REG_c, "%ebx", "%edx", "%esi", "memory"
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#endif /* BRANCHLESS_CABAC_DECODER */
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#else /* ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) */
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int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
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int bit, lps_mask av_unused;
545
c->range -= RangeLPS;
546
#ifndef BRANCHLESS_CABAC_DECODER
547
if(c->low < (c->range<<(CABAC_BITS+1))){
549
*state= ff_h264_mps_state[s];
550
renorm_cabac_decoder_once(c);
552
bit= ff_h264_norm_shift[RangeLPS];
553
c->low -= (c->range<<(CABAC_BITS+1));
554
*state= ff_h264_lps_state[s];
555
c->range = RangeLPS<<bit;
559
if(!(c->low & CABAC_MASK)){
563
#else /* BRANCHLESS_CABAC_DECODER */
564
lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
566
c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
567
c->range += (RangeLPS - c->range) & lps_mask;
570
*state= (ff_h264_mlps_state+128)[s];
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lps_mask= ff_h264_norm_shift[c->range];
574
c->range<<= lps_mask;
576
if(!(c->low & CABAC_MASK))
578
#endif /* BRANCHLESS_CABAC_DECODER */
579
#endif /* ARCH_X86 && HAVE_7REGS && HAVE_EBX_AVAILABLE && !defined(BROKEN_RELOCATIONS) */
583
static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
584
return get_cabac_inline(c,state);
587
static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
588
return get_cabac_inline(c,state);
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static int av_unused get_cabac_bypass(CABACContext *c){
595
"movl "RANGE "(%1), %%ebx \n\t"
596
"movl "LOW "(%1), %%eax \n\t"
597
"shl $17, %%ebx \n\t"
598
"add %%eax, %%eax \n\t"
599
"sub %%ebx, %%eax \n\t"
601
"and %%edx, %%ebx \n\t"
602
"add %%ebx, %%eax \n\t"
603
"test %%ax, %%ax \n\t"
605
"movl "BYTE "(%1), %%"REG_b" \n\t"
606
"subl $0xFFFF, %%eax \n\t"
607
"movzwl (%%"REG_b"), %%ecx \n\t"
609
"shrl $15, %%ecx \n\t"
610
"addl $2, %%"REG_b" \n\t"
611
"addl %%ecx, %%eax \n\t"
612
"movl %%"REG_b", "BYTE "(%1) \n\t"
614
"movl %%eax, "LOW "(%1) \n\t"
618
: "%eax", "%"REG_b, "%ecx", "memory"
625
if(!(c->low & CABAC_MASK))
628
range= c->range<<(CABAC_BITS+1);
639
static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
640
#if ARCH_X86 && HAVE_EBX_AVAILABLE
642
"movl "RANGE "(%1), %%ebx \n\t"
643
"movl "LOW "(%1), %%eax \n\t"
644
"shl $17, %%ebx \n\t"
645
"add %%eax, %%eax \n\t"
646
"sub %%ebx, %%eax \n\t"
648
"and %%edx, %%ebx \n\t"
649
"add %%ebx, %%eax \n\t"
650
"xor %%edx, %%ecx \n\t"
651
"sub %%edx, %%ecx \n\t"
652
"test %%ax, %%ax \n\t"
654
"mov "BYTE "(%1), %%"REG_b" \n\t"
655
"subl $0xFFFF, %%eax \n\t"
656
"movzwl (%%"REG_b"), %%edx \n\t"
658
"shrl $15, %%edx \n\t"
659
"add $2, %%"REG_b" \n\t"
660
"addl %%edx, %%eax \n\t"
661
"mov %%"REG_b", "BYTE "(%1) \n\t"
663
"movl %%eax, "LOW "(%1) \n\t"
667
: "%eax", "%"REG_b, "%edx", "memory"
674
if(!(c->low & CABAC_MASK))
677
range= c->range<<(CABAC_BITS+1);
682
return (val^mask)-mask;
688
* @return the number of bytes read or 0 if no end
690
static int av_unused get_cabac_terminate(CABACContext *c){
692
if(c->low < c->range<<(CABAC_BITS+1)){
693
renorm_cabac_decoder_once(c);
696
return c->bytestream - c->bytestream_start;
702
* Get (truncated) unary binarization.
704
static int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){
707
for(i=0; i<max; i++){
708
if(get_cabac(c, state)==0)
711
if(i< max_index) state++;
714
return truncated ? max : -1;
718
* get unary exp golomb k-th order binarization.
720
static int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signed, int k, int max_index){
724
if(get_cabac(c, state)==0)
727
if(0 < max_index) state++;
729
for(i=1; i<max; i++){
730
if(get_cabac(c, state)==0){
731
if(is_signed && get_cabac_bypass(c)){
737
if(i < max_index) state++;
740
while(get_cabac_bypass(c)){
747
v+= v + get_cabac_bypass(c);
751
if(is_signed && get_cabac_bypass(c)){
758
#endif /* AVCODEC_CABAC_H */