* Range coder
* Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
*
- * This library is free software; you can redistribute it and/or
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ * version 2.1 of the License, or (at your option) any later version.
*
- * This library is distributed in the hope that it will be useful,
+ * FFmpeg 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
- *
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-
+
/**
- * @file rangecoder.c
+ * @file libavcodec/rangecoder.c
* Range coder.
* based upon
* "Range encoding: an algorithm for removing redundancy from a digitised
#include <string.h>
#include "avcodec.h"
-#include "common.h"
#include "rangecoder.h"
+#include "bytestream.h"
void ff_init_range_encoder(RangeCoder *c, uint8_t *buf, int buf_size){
- c->bytestream_start=
+ c->bytestream_start=
c->bytestream= buf;
c->bytestream_end= buf + buf_size;
/* cast to avoid compiler warning */
ff_init_range_encoder(c, (uint8_t *) buf, buf_size);
- c->low =(*c->bytestream++)<<8;
- c->low+= *c->bytestream++;
+ c->low = bytestream_get_be16(&c->bytestream);
}
void ff_build_rac_states(RangeCoder *c, int factor, int max_p){
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++){
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])
+ if(c->one_state[i])
continue;
p= (i*one + 128) >> 8;
if(p8 > max_p) p8= max_p;
c->one_state[ i]= p8;
}
-
- for(i=0; i<256; i++)
+
+ for(i=1; i<255; 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 c->bytestream - c->bytestream_start;
}
-#if 0 //selftest
+#ifdef TEST
#define SIZE 10240
-int main(){
+
+#include "libavutil/lfg.h"
+
+int main(void){
RangeCoder c;
uint8_t b[9*SIZE];
uint8_t r[9*SIZE];
int i;
uint8_t state[10]= {0};
-
+ AVLFG prng;
+
+ av_lfg_init(&prng, 1);
+
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;
+ r[i] = av_lfg_get(&prng) % 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_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
+#endif /* TEST */