ffmpeg/libavcodec/rl.c

127 lines
4.0 KiB
C

/*
* 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
*/
#include <stdint.h>
#include <string.h>
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "rl.h"
av_cold void ff_rl_init_level_run(uint8_t max_level[MAX_LEVEL + 1],
uint8_t index_run[MAX_RUN + 1],
const uint8_t table_run[/* n */],
const uint8_t table_level[/* n*/],
int n)
{
memset(index_run, n, MAX_RUN + 1);
for (int i = 0; i < n; i++) {
int run = table_run[i];
int level = table_level[i];
if (index_run[run] == n)
index_run[run] = i;
if (level > max_level[run])
max_level[run] = level;
}
}
av_cold void ff_rl_init(RLTable *rl,
uint8_t static_store[2][2 * MAX_RUN + MAX_LEVEL + 3])
{
int last, run, level, start, end, i;
/* compute max_level[], max_run[] and index_run[] */
for (last = 0; last < 2; last++) {
int8_t *max_level = static_store[last];
int8_t *max_run = static_store[last] + MAX_RUN + 1;
uint8_t *index_run = static_store[last] + MAX_RUN + 1 + MAX_LEVEL + 1;
if (last == 0) {
start = 0;
end = rl->last;
} else {
start = rl->last;
end = rl->n;
}
memset(index_run, rl->n, MAX_RUN + 1);
for (i = start; i < end; i++) {
run = rl->table_run[i];
level = rl->table_level[i];
if (index_run[run] == rl->n)
index_run[run] = i;
if (level > max_level[run])
max_level[run] = level;
if (run > max_run[level])
max_run[level] = run;
}
rl->max_level[last] = max_level;
rl->max_run[last] = max_run;
rl->index_run[last] = index_run;
}
}
av_cold void ff_rl_init_vlc(RLTable *rl, unsigned static_size)
{
int i, q;
VLCElem table[1500] = { 0 };
VLC vlc = { .table = table, .table_allocated = static_size };
av_assert0(static_size <= FF_ARRAY_ELEMS(table));
vlc_init(&vlc, 9, rl->n + 1,
&rl->table_vlc[0][1], 4, 2,
&rl->table_vlc[0][0], 4, 2, VLC_INIT_USE_STATIC);
for (q = 0; q < 32; q++) {
int qmul = q * 2;
int qadd = (q - 1) | 1;
if (!rl->rl_vlc[q])
return;
if (q == 0) {
qmul = 1;
qadd = 0;
}
for (i = 0; i < vlc.table_size; i++) {
int code = vlc.table[i].sym;
int len = vlc.table[i].len;
int level, run;
if (len == 0) { // illegal code
run = 66;
level = MAX_LEVEL;
} else if (len < 0) { // more bits needed
run = 0;
level = code;
} else {
if (code == rl->n) { // esc
run = 66;
level = 0;
} else {
run = rl->table_run[code] + 1;
level = rl->table_level[code] * qmul + qadd;
if (code >= rl->last) run += 192;
}
}
rl->rl_vlc[q][i].len = len;
rl->rl_vlc[q][i].level = level;
rl->rl_vlc[q][i].run = run;
}
}
}