RepoMirrors
/
ffmpeg
mirror of https://git.ffmpeg.org/ffmpeg.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

avcodec/lagarith: use VLC for prob code length

This commit is contained in:
Paul B Mahol 2023-09-12 01:29:55 +02:00
parent 1ac2769009
commit f7dc5d76e0
1 changed files with 38 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
libavcodec/lagarith.c
View File

@ -27,6 +27,8 @@
#include <inttypes.h>
#include "libavutil/thread.h"
#include "avcodec.h"
#include "codec_internal.h"
#include "get_bits.h"
@ -35,6 +37,8 @@
#include "lossless_videodsp.h"
#include "thread.h"
#define VLC_BITS 7
enum LagarithFrameType {
FRAME_RAW = 1, /**< uncompressed */
FRAME_U_RGB24 = 2, /**< unaligned RGB24 */
@ -56,6 +60,35 @@ typedef struct LagarithContext {
int zeros_rem; /**< number of zero bytes remaining to output */
} LagarithContext;
static VLC lag_tab;
static const uint8_t lag_bits[] = {
7, 7, 2, 7, 3, 4, 5, 6, 7, 7, 7, 7, 7, 6, 7, 4, 5, 7, 7, 7, 7,
5, 6, 7, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
};
static const uint8_t lag_codes[] = {
0x01, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x05,
0x08, 0x09, 0x0A, 0x0B, 0x0B, 0x0B, 0x0B, 0x10, 0x11, 0x12, 0x13,
0x13, 0x13, 0x14, 0x15, 0x20, 0x21, 0x22, 0x23, 0x23, 0x24, 0x25,
0x28, 0x29, 0x2A, 0x2B, 0x2B, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
0x48, 0x49, 0x4A, 0x4B, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55,
};
static const uint8_t lag_symbols[] = {
20, 12, 0, 12, 1, 2, 4, 7, 7, 28, 4, 25, 17,
10, 17, 3, 6, 2, 23, 15, 15, 5, 9, 10, 31, 1, 22,
14, 14, 8, 9, 30, 6, 27, 19, 11, 19, 0, 21, 13, 13,
8, 29, 5, 26, 18, 18, 3, 24, 16, 16, 11, 32,
};
static av_cold void lag_init_static_data(void)
{
VLC_INIT_SPARSE_STATIC(&lag_tab, VLC_BITS, FF_ARRAY_ELEMS(lag_bits),
lag_bits, 1, 1, lag_codes, 1, 1, lag_symbols, 1, 1, 128);
}
/**
* Compute the 52-bit mantissa of 1/(double)denom.
* This crazy format uses floats in an entropy coder and we have to match x86
@ -101,23 +134,10 @@ static uint8_t lag_calc_zero_run(int8_t x)
static int lag_decode_prob(GetBitContext *gb, uint32_t *value)
{
static const uint8_t series[] = { 1, 2, 3, 5, 8, 13, 21 };
int i;
int bit = 0;
int bits = 0;
int prevbit = 0;
unsigned val;
unsigned val, bits;
for (i = 0; i < 7; i++) {
if (prevbit && bit)
break;
prevbit = bit;
bit = get_bits1(gb);
if (bit && !prevbit)
bits += series[i];
}
bits--;
if (bits < 0 || bits > 31) {
bits = get_vlc2(gb, lag_tab.table, VLC_BITS, 1);
if (bits > 31) {
*value = 0;
return AVERROR_INVALIDDATA;
} else if (bits == 0) {
@ -720,10 +740,12 @@ static int lag_decode_frame(AVCodecContext *avctx, AVFrame *p,
static av_cold int lag_decode_init(AVCodecContext *avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
LagarithContext *l = avctx->priv_data;
l->avctx = avctx;
ff_llviddsp_init(&l->llviddsp);
ff_thread_once(&init_static_once, lag_init_static_data);
return 0;
}