* 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 Libav.
+ *
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
*/
/**
- * @file rangecoder.c
+ * @file
* Range coder.
* based upon
* "Range encoding: an algorithm for removing redundancy from a digitised
* 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 "libavutil/attributes.h"
+#include "libavutil/intreadwrite.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;
+av_cold 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){
+av_cold void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf,
+ int buf_size)
+{
/* cast to avoid compiler warning */
- ff_init_range_encoder(c, (uint8_t *) buf, buf_size);
+ ff_init_range_encoder(c, (uint8_t *)buf, buf_size);
- c->low =(*c->bytestream++)<<8;
- c->low+= *c->bytestream++;
+ c->low = AV_RB16(c->bytestream);
+ c->bytestream += 2;
}
-void ff_build_rac_states(RangeCoder *c, int factor, int max_p){
- const int64_t one= 1LL<<32;
+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;
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;
+ memset(c->one_state, 0, sizeof(c->one_state));
+
+ 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])
+
+ 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;
+ 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
+ for (i = 1; i < 255; i++)
+ c->zero_state[i] = 256 - c->one_state[256 - i];
}
-/**
- *
- * @return the number of bytes written
- */
-int ff_rac_terminate(RangeCoder *c){
- c->range=0xFF;
- c->low +=0xFF;
+/* Return the number of bytes written. */
+int ff_rac_terminate(RangeCoder *c)
+{
+ c->range = 0xFF;
+ c->low += 0xFF;
renorm_encoder(c);
- c->range=0xFF;
+ c->range = 0xFF;
renorm_encoder(c);
- assert(c->low == 0);
+ 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
projects / ffmpeg / blobdiff