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avcodec/vmixdec: add support for custom first byte

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This commit is contained in:
Paul B Mahol 2023-09-14 14:45:22 +02:00
parent 038b992256
commit 00a837c70c
1 changed files with 27 additions and 9 deletions
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36
libavcodec/vmixdec.c
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@ -23,7 +23,6 @@
#include <stdlib.h>
#include <string.h>
#include "libavutil/avassert.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem_internal.h"
@ -45,6 +44,7 @@ typedef struct SliceContext {
typedef struct VMIXContext {
int nb_slices;
int lshift;
int16_t factors[64];
uint8_t scan[64];
@ -55,9 +55,22 @@ typedef struct VMIXContext {
IDCTDSPContext idsp;
} VMIXContext;
static const uint8_t quality[25] = {
1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16,
18, 20, 22, 24, 28, 32, 36, 40, 44, 48, 52, 56, 64,
static const uint8_t quality[256] = {
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 64, 56, 52, 48, 44,
12, 36, 32, 28, 24, 22, 20, 18, 16, 14, 12, 10, 8, 7, 6, 5,
4, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
};
static const uint8_t quant[64] = {
@ -108,6 +121,7 @@ static int decode_dcac(AVCodecContext *avctx,
const uint8_t *scan = s->scan;
const int add = plane ? 0 : 1024;
int i, dc_v = 0, ac_v = 0, dc = 0;
const int lshift = s->lshift;
for (int y = 0; y < 2; y++) {
for (int x = 0; x < width; x += 8) {
@ -139,7 +153,7 @@ static int decode_dcac(AVCodecContext *avctx,
ac_run = get_ue_golomb_long(ac_gb);
}
block[0] = dc + add;
block[0] = (dc << lshift) + add;
s->idsp.idct_put(dst + x, linesize, block);
}
@ -213,18 +227,22 @@ static int decode_frame(AVCodecContext *avctx,
AVPacket *avpkt)
{
VMIXContext *s = avctx->priv_data;
unsigned offset = 3, q;
unsigned offset, q;
int ret;
if (avpkt->size <= 7)
return AVERROR_INVALIDDATA;
if (avpkt->data[0] != 0x01)
s->lshift = 0;
offset = 2 + avpkt->data[0];
if (offset == 5)
s->lshift = avpkt->data[1];
else if (offset != 3)
return AVERROR_INVALIDDATA;
q = av_clip(99 - av_clip(avpkt->data[1], 0, 99), 0, FF_ARRAY_ELEMS(quality) - 1);
q = quality[avpkt->data[offset - 2]];
for (int n = 0; n < 64; n++)
s->factors[n] = quant[n] * quality[q];
s->factors[n] = quant[n] * q;
s->nb_slices = (avctx->height + 15) / 16;
av_fast_mallocz(&s->slices, &s->slices_size, s->nb_slices * sizeof(*s->slices));