mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-28 20:53:54 +02:00
558 lines
16 KiB
C
558 lines
16 KiB
C
/*
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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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*
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* This file is part of Libav.
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*
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* Libav 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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*
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* Libav 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; 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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*/
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/**
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* @file
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* Context Adaptive Binary Arithmetic Coder.
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*/
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#ifndef AVCODEC_CABAC_H
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#define AVCODEC_CABAC_H
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#include <stddef.h>
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#include "put_bits.h"
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//#undef NDEBUG
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#include <assert.h>
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#include "libavutil/x86_cpu.h"
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#define CABAC_BITS 16
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#define CABAC_MASK ((1<<CABAC_BITS)-1)
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typedef struct CABACContext{
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int low;
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int range;
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int outstanding_count;
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#ifdef STRICT_LIMITS
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int symCount;
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#endif
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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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PutBitContext pb;
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}CABACContext;
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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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}
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}
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static inline void renorm_cabac_encoder(CABACContext *c){
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while(c->range < 0x100){
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//FIXME optimize
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if(c->low<0x100){
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put_cabac_bit(c, 0);
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}else if(c->low<0x200){
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c->outstanding_count++;
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c->low -= 0x100;
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}else{
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put_cabac_bit(c, 1);
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c->low -= 0x200;
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}
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c->range+= c->range;
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c->low += c->low;
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}
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}
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#ifdef TEST
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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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c->range -= RangeLPS;
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*state= ff_h264_mps_state[*state];
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}else{
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c->low += c->range - RangeLPS;
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c->range = RangeLPS;
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*state= ff_h264_lps_state[*state];
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}
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renorm_cabac_encoder(c);
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#ifdef STRICT_LIMITS
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c->symCount++;
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#endif
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}
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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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if(!bit){
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c->range -= RangeLPS;
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}else{
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c->low += c->range - RangeLPS;
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c->range = RangeLPS;
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}
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renorm_cabac_encoder(c);
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#ifdef STRICT_LIMITS
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c->symCount++;
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#endif
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}
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/**
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* @param bit 0 -> write zero bit, !=0 write one bit
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*/
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static void put_cabac_bypass(CABACContext *c, int bit){
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c->low += c->low;
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if(bit){
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c->low += c->range;
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}
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//FIXME optimize
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if(c->low<0x200){
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put_cabac_bit(c, 0);
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}else if(c->low<0x400){
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c->outstanding_count++;
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c->low -= 0x200;
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}else{
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put_cabac_bit(c, 1);
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c->low -= 0x400;
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}
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#ifdef STRICT_LIMITS
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c->symCount++;
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#endif
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}
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/**
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*
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* @return the number of bytes written
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*/
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static int put_cabac_terminate(CABACContext *c, int bit){
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c->range -= 2;
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if(!bit){
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renorm_cabac_encoder(c);
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}else{
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c->low += c->range;
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c->range= 2;
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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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}
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#ifdef STRICT_LIMITS
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c->symCount++;
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#endif
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return (put_bits_count(&c->pb)+7)>>3;
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}
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/**
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* put (truncated) unary binarization.
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*/
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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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int i;
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assert(v <= max);
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#if 1
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for(i=0; i<v; i++){
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put_cabac(c, state, 1);
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if(i < max_index) state++;
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}
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if(truncated==0 || v<max)
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put_cabac(c, state, 0);
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#else
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if(v <= max_index){
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for(i=0; i<v; i++){
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put_cabac(c, state+i, 1);
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}
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if(truncated==0 || v<max)
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put_cabac(c, state+i, 0);
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}else{
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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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}
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for(; i<v; i++){
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put_cabac(c, state+max_index, 1);
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}
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if(truncated==0 || v<max)
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put_cabac(c, state+max_index, 0);
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}
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#endif
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}
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/**
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* put unary exp golomb k-th order binarization.
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*/
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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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int i;
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if(v==0)
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put_cabac(c, state, 0);
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else{
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const int sign= v < 0;
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if(is_signed) v= FFABS(v);
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if(v<max){
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for(i=0; i<v; i++){
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put_cabac(c, state, 1);
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if(i < max_index) state++;
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}
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put_cabac(c, state, 0);
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}else{
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int m= 1<<k;
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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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}
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v -= max;
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while(v >= m){ //FIXME optimize
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put_cabac_bypass(c, 1);
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v-= m;
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m+= m;
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}
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put_cabac_bypass(c, 0);
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while(m>>=1){
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put_cabac_bypass(c, v&m);
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}
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}
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if(is_signed)
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put_cabac_bypass(c, sign);
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}
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}
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#endif /* TEST */
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static void refill(CABACContext *c){
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#if CABAC_BITS == 16
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c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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#else
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c->low+= c->bytestream[0]<<1;
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#endif
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c->low -= CABAC_MASK;
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c->bytestream+= CABAC_BITS/8;
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}
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#if ! ( ARCH_X86 && HAVE_7REGS && !defined(BROKEN_RELOCATIONS) )
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static void refill2(CABACContext *c){
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int i, x;
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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= -CABAC_MASK;
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#if CABAC_BITS == 16
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x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
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#else
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x+= c->bytestream[0]<<1;
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#endif
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c->low += x<<i;
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c->bytestream+= CABAC_BITS/8;
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}
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#endif
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static inline void renorm_cabac_decoder(CABACContext *c){
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while(c->range < 0x100){
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c->range+= c->range;
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c->low+= c->low;
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if(!(c->low & CABAC_MASK))
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refill(c);
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}
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}
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static inline void renorm_cabac_decoder_once(CABACContext *c){
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int shift= (uint32_t)(c->range - 0x100)>>31;
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c->range<<= shift;
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c->low <<= shift;
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if(!(c->low & CABAC_MASK))
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refill(c);
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}
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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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#if ARCH_X86 && HAVE_7REGS && !defined(BROKEN_RELOCATIONS)
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int bit, low, range, tmp;
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#if HAVE_FAST_CMOV
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp)\
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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)\
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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, byte) \
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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)\
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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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" jnz 1f \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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"bswap "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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"neg %%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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"1: \n\t"
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__asm__ volatile(
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"movl %a6(%5), %2 \n\t"
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"movl %a7(%5), %1 \n\t"
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BRANCHLESS_GET_CABAC("%0", "%5", "(%4)", "%1", "%w1", "%2", "%3", "%b3", "%a8")
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"movl %2, %a6(%5) \n\t"
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"movl %1, %a7(%5) \n\t"
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:"=&r"(bit), "=&r"(low), "=&r"(range), "=&r"(tmp)
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:"r"(state), "r"(c),
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"i"(offsetof(CABACContext, range)), "i"(offsetof(CABACContext, low)),
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"i"(offsetof(CABACContext, bytestream))
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: "%"REG_c, "memory"
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);
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bit&=1;
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#else /* ARCH_X86 && HAVE_7REGS && !defined(BROKEN_RELOCATIONS) */
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int s = *state;
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int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
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int bit, lps_mask;
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c->range -= RangeLPS;
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lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
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c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
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c->range += (RangeLPS - c->range) & lps_mask;
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s^=lps_mask;
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*state= (ff_h264_mlps_state+128)[s];
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bit= s&1;
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lps_mask= ff_h264_norm_shift[c->range];
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c->range<<= lps_mask;
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c->low <<= lps_mask;
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if(!(c->low & CABAC_MASK))
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refill2(c);
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#endif /* ARCH_X86 && HAVE_7REGS && !defined(BROKEN_RELOCATIONS) */
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return bit;
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}
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static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
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return get_cabac_inline(c,state);
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}
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static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
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return get_cabac_inline(c,state);
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}
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static int av_unused get_cabac_bypass(CABACContext *c){
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int range;
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c->low += c->low;
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if(!(c->low & CABAC_MASK))
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refill(c);
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range= c->range<<(CABAC_BITS+1);
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if(c->low < range){
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return 0;
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}else{
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c->low -= range;
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return 1;
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}
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}
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static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
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#if ARCH_X86
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x86_reg tmp;
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__asm__ volatile(
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"movl %a3(%2), %k1 \n\t"
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"movl %a4(%2), %%eax \n\t"
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"shl $17, %k1 \n\t"
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"add %%eax, %%eax \n\t"
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"sub %k1, %%eax \n\t"
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"cltd \n\t"
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"and %%edx, %k1 \n\t"
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"add %k1, %%eax \n\t"
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"xor %%edx, %%ecx \n\t"
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"sub %%edx, %%ecx \n\t"
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"test %%ax, %%ax \n\t"
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" jnz 1f \n\t"
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"mov %a5(%2), %1 \n\t"
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"subl $0xFFFF, %%eax \n\t"
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"movzwl (%1), %%edx \n\t"
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"bswap %%edx \n\t"
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"shrl $15, %%edx \n\t"
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"add $2, %1 \n\t"
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"addl %%edx, %%eax \n\t"
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"mov %1, %a5(%2) \n\t"
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"1: \n\t"
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"movl %%eax, %a4(%2) \n\t"
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:"+c"(val), "=&r"(tmp)
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:"r"(c),
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"i"(offsetof(CABACContext, range)), "i"(offsetof(CABACContext, low)),
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"i"(offsetof(CABACContext, bytestream))
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: "%eax", "%edx", "memory"
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);
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return val;
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#else
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int range, mask;
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c->low += c->low;
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if(!(c->low & CABAC_MASK))
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refill(c);
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range= c->range<<(CABAC_BITS+1);
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|
c->low -= range;
|
|
mask= c->low >> 31;
|
|
range &= mask;
|
|
c->low += range;
|
|
return (val^mask)-mask;
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @return the number of bytes read or 0 if no end
|
|
*/
|
|
static int av_unused get_cabac_terminate(CABACContext *c){
|
|
c->range -= 2;
|
|
if(c->low < c->range<<(CABAC_BITS+1)){
|
|
renorm_cabac_decoder_once(c);
|
|
return 0;
|
|
}else{
|
|
return c->bytestream - c->bytestream_start;
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
/**
|
|
* Get (truncated) unary binarization.
|
|
*/
|
|
static 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 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;
|
|
}
|
|
#endif /* 0 */
|
|
|
|
#endif /* AVCODEC_CABAC_H */
|