range coder

Originally committed as revision 3654 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-10-30 01:43:37 +00:00
parent 9287acd197
commit 672a19aac2
3 changed files with 308 additions and 1 deletions

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@ -21,7 +21,7 @@ OBJS= common.o utils.o mem.o allcodecs.o \
msvideo1.o vqavideo.o idcinvideo.o adx.o rational.o faandct.o 8bps.o \
smc.o parser.o flicvideo.o truemotion1.o vmdav.o lcl.o qtrle.o g726.o \
flac.o vp3dsp.o integer.o snow.o tscc.o sonic.o ulti.o h264idct.o \
qdrw.o xl.o
qdrw.o xl.o rangecoder.o
ifeq ($(AMR_NB),yes)
ifeq ($(AMR_NB_FIXED),yes)

178
libavcodec/rangecoder.c Normal file
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@ -0,0 +1,178 @@
/*
* Range coder
* Copyright (c) 2004 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 rangecoder.c
* Range coder.
* based upon
* "Range encoding: an algorithm for removing redundancy from a digitised
* message.
* G. N. N. Martin Presented in March 1979 to the Video &
* Data Recording Conference,
* IBM UK Scientific Center held in Southampton July 24-27 1979."
*
*/
#include <string.h>
#include "avcodec.h"
#include "common.h"
#include "rangecoder.h"
void ff_init_range_encoder(RangeCoder *c, uint8_t *buf, int buf_size){
c->bytestream_start=
c->bytestream= buf;
c->bytestream_end= buf + buf_size;
c->low= 0;
c->range= 0xFF00;
c->outstanding_count= 0;
c->outstanding_byte= -1;
}
void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf, int buf_size){
ff_init_range_encoder(c, buf, buf_size);
c->low =(*c->bytestream++)<<8;
c->low+= *c->bytestream++;
}
void ff_build_rac_states(RangeCoder *c, int factor, int max_p){
const int64_t one= 1LL<<32;
int64_t p;
int last_p8, p8, i, j;
memset(c->zero_state, 0, sizeof(c->zero_state));
memset(c-> one_state, 0, sizeof(c-> one_state));
#if 0
for(i=1; i<256; i++){
if(c->one_state[i])
continue;
p= (i*one + 128) >> 8;
last_p8= i;
for(;;){
p+= ((one-p)*factor + one/2) >> 32;
p8= (256*p + one/2) >> 32; //FIXME try without the one
if(p8 <= last_p8) p8= last_p8+1;
if(p8 > max_p) p8= max_p;
if(p8 < last_p8)
break;
c->one_state[last_p8]= p8;
if(p8 == last_p8)
break;
last_p8= p8;
}
}
#endif
#if 1
last_p8= 0;
p= one/2;
for(i=0; i<128; i++){
p8= (256*p + one/2) >> 32; //FIXME try without the one
if(p8 <= last_p8) p8= last_p8+1;
if(last_p8 && last_p8<256 && p8<=max_p)
c->one_state[last_p8]= p8;
p+= ((one-p)*factor + one/2) >> 32;
last_p8= p8;
}
#endif
for(i=256-max_p; i<=max_p; i++){
if(c->one_state[i])
continue;
p= (i*one + 128) >> 8;
p+= ((one-p)*factor + one/2) >> 32;
p8= (256*p + one/2) >> 32; //FIXME try without the one
if(p8 <= i) p8= i+1;
if(p8 > max_p) p8= max_p;
c->one_state[ i]= p8;
}
for(i=0; i<256; i++)
c->zero_state[i]= 256-c->one_state[256-i];
#if 0
for(i=0; i<256; i++)
av_log(NULL, AV_LOG_DEBUG, "%3d %3d\n", i, c->one_state[i]);
#endif
}
/**
*
* @return the number of bytes written
*/
int ff_rac_terminate(RangeCoder *c){
c->range=0xFF;
c->low +=0xFF;
renorm_encoder(c);
c->range=0xFF;
renorm_encoder(c);
assert(c->low == 0);
assert(c->range >= 0x100);
return c->bytestream - c->bytestream_start;
}
#if 0 //selftest
#define SIZE 10240
int main(){
RangeCoder c;
uint8_t b[9*SIZE];
uint8_t r[9*SIZE];
int i;
uint8_t state[10]= {0};
ff_init_range_encoder(&c, b, SIZE);
ff_build_rac_states(&c, 0.05*(1LL<<32), 128+64+32+16);
memset(state, 128, sizeof(state));
for(i=0; i<SIZE; i++){
r[i]= random()%7;
}
for(i=0; i<SIZE; i++){
START_TIMER
put_rac(&c, state, r[i]&1);
STOP_TIMER("put_rac")
}
ff_put_rac_terminate(&c);
ff_init_range_decoder(&c, b, SIZE);
memset(state, 128, sizeof(state));
for(i=0; i<SIZE; i++){
START_TIMER
if( (r[i]&1) != get_rac(&c, state) )
av_log(NULL, AV_LOG_DEBUG, "rac failure at %d\n", i);
STOP_TIMER("get_rac")
}
return 0;
}
#endif

129
libavcodec/rangecoder.h Normal file
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@ -0,0 +1,129 @@
/*
* Range coder
* Copyright (c) 2004 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 rangecoder.h
* Range coder.
*/
#undef NDEBUG
#include <assert.h>
typedef struct RangeCoder{
int low;
int range;
int outstanding_count;
int outstanding_byte;
uint8_t zero_state[256];
uint8_t one_state[256];
uint8_t *bytestream_start;
uint8_t *bytestream;
uint8_t *bytestream_end;
}RangeCoder;
void ff_init_range_encoder(RangeCoder *c, uint8_t *buf, int buf_size);
void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf, int buf_size);
int ff_rac_terminate(RangeCoder *c);
void ff_build_rac_states(RangeCoder *c, int factor, int max_p);
static inline void renorm_encoder(RangeCoder *c){
//FIXME optimize
while(c->range < 0x100){
if(c->outstanding_byte < 0){
c->outstanding_byte= c->low>>8;
}else if(c->low <= 0xFF00){
*c->bytestream++ = c->outstanding_byte;
for(;c->outstanding_count; c->outstanding_count--)
*c->bytestream++ = 0xFF;
c->outstanding_byte= c->low>>8;
}else if(c->low >= 0x10000){
*c->bytestream++ = c->outstanding_byte + 1;
for(;c->outstanding_count; c->outstanding_count--)
*c->bytestream++ = 0x00;
c->outstanding_byte= (c->low>>8) & 0xFF;
}else{
c->outstanding_count++;
}
c->low = (c->low & 0xFF)<<8;
c->range <<= 8;
}
}
static inline void put_rac(RangeCoder *c, uint8_t * const state, int bit){
int range1= (c->range * (*state)) >> 8;
assert(*state);
assert(range1 < c->range);
assert(range1 > 0);
if(!bit){
c->range -= range1;
*state= c->zero_state[*state];
}else{
c->low += c->range - range1;
c->range = range1;
*state= c->one_state[*state];
}
renorm_encoder(c);
}
static inline void refill(RangeCoder *c){
if(c->range < 0x100){
c->range <<= 8;
c->low <<= 8;
if(c->bytestream < c->bytestream_end)
c->low+= c->bytestream[0];
c->bytestream++;
}
}
static inline int get_rac(RangeCoder *c, uint8_t * const state){
int range1= (c->range * (*state)) >> 8;
int one_mask;
c->range -= range1;
#if 1
if(c->low < c->range){
*state= c->zero_state[*state];
refill(c);
return 0;
}else{
c->low -= c->range;
*state= c->one_state[*state];
c->range = range1;
refill(c);
return 1;
}
#else
one_mask= (c->range - c->low-1)>>31;
c->low -= c->range & one_mask;
c->range += (range1 - c->range) & one_mask;
*state= c->zero_state[(*state) + (256&one_mask)];
refill(c);
return one_mask&1;
#endif
}