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/**
* @file libavcodec/vorbis.c
* Common code for Vorbis I encoder and decoder
* @author Denes Balatoni ( dbalatoni programozo hu )
* 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 2.1 of the License, or (at your option) any later version.
*
* 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#undef V_DEBUG
//#define V_DEBUG
#define ALT_BITSTREAM_READER_LE
#include "avcodec.h"
#include "get_bits.h"
#include "vorbis.h"
/* Helper functions */
unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n) { // x^(1/n)
unsigned int ret=0, i, j;
do {
++ret;
for(i=0,j=ret;i<n-1;i++) j*=ret;
} while (j<=x);
return ret - 1;
}
// Generate vlc codes from vorbis huffman code lengths
// the two bits[p] > 32 checks should be redundant, all calling code should
// already ensure that, but since it allows overwriting the stack it seems
// reasonable to check redundantly.
int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num) {
uint_fast32_t exit_at_level[33]={404,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint_fast8_t i,j;
uint_fast32_t code,p;
#ifdef V_DEBUG
GetBitContext gb;
#endif
for(p=0;(bits[p]==0) && (p<num);++p);
if (p==num) {
// av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");
return 0;
}
codes[p]=0;
if (bits[p] > 32) return 1;
for(i=0;i<bits[p];++i) {
exit_at_level[i+1]=1<<i;
}
#ifdef V_DEBUG
av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]);
init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
for(i=0;i<bits[p];++i) {
av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
}
av_log(NULL, AV_LOG_INFO, "\n");
#endif
++p;
for(;p<num;++p) {
if (bits[p] > 32) return 1;
if (bits[p]==0) continue;
// find corresponding exit(node which the tree can grow further from)
for(i=bits[p];i>0;--i) {
if (exit_at_level[i]) break;
}
if (!i) return 1; // overspecified tree
code=exit_at_level[i];
exit_at_level[i]=0;
// construct code (append 0s to end) and introduce new exits
for(j=i+1;j<=bits[p];++j) {
exit_at_level[j]=code+(1<<(j-1));
}
codes[p]=code;
#ifdef V_DEBUG
av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
for(i=0;i<bits[p];++i) {
av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
}
av_log(NULL, AV_LOG_INFO, "\n");
#endif
}
//no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
for (p=1; p<33; p++)
if (exit_at_level[p]) return 1;
return 0;
}
void ff_vorbis_ready_floor1_list(vorbis_floor1_entry * list, int values) {
int i;
list[0].sort = 0;
list[1].sort = 1;
for (i = 2; i < values; i++) {
int j;
list[i].low = 0;
list[i].high = 1;
list[i].sort = i;
for (j = 2; j < i; j++) {
int tmp = list[j].x;
if (tmp < list[i].x) {
if (tmp > list[list[i].low].x) list[i].low = j;
} else {
if (tmp < list[list[i].high].x) list[i].high = j;
}
}
}
for (i = 0; i < values - 1; i++) {
int j;
for (j = i + 1; j < values; j++) {
if (list[list[i].sort].x > list[list[j].sort].x) {
int tmp = list[i].sort;
list[i].sort = list[j].sort;
list[j].sort = tmp;
}
}
}
}
static void render_line(int x0, int y0, int x1, int y1, float * buf) {
int dy = y1 - y0;
int adx = x1 - x0;
int base = dy / adx;
int ady = FFABS(dy) - FFABS(base) * adx;
int x = x0;
int y = y0;
int err = 0;
int sy = dy<0 ? -1 : 1;
buf[x] = ff_vorbis_floor1_inverse_db_table[y];
while (++x < x1) {
err += ady;
if (err >= adx) {
err -= adx;
y += sy;
}
y += base;
buf[x] = ff_vorbis_floor1_inverse_db_table[y];
}
}
void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values, uint_fast16_t * y_list, int * flag, int multiplier, float * out, int samples) {
int lx, ly, i;
lx = 0;
ly = y_list[0] * multiplier;
for (i = 1; i < values; i++) {
int pos = list[i].sort;
if (flag[pos]) {
int x1 = list[pos].x;
int y1 = y_list[pos] * multiplier;
if (lx < samples)
render_line(lx, ly, FFMIN(x1,samples), y1, out);
lx = x1;
ly = y1;
}
if (lx >= samples) break;
}
if (lx < samples) render_line(lx, ly, samples, ly, out);
}
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