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lavc/mjpegdec: speed up scan data copy

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This commit is contained in:
Matthieu Bouron 2016-01-26 17:15:37 +01:00
parent e5b5676c00
commit 0d733ec379
1 changed files with 40 additions and 10 deletions
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50
libavcodec/mjpegdec.c
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@ -1921,24 +1921,54 @@ int ff_mjpeg_find_marker(MJpegDecodeContext *s,
/* unescape buffer of SOS, use special treatment for JPEG-LS */
if (start_code == SOS && !s->ls) {
const uint8_t *src = *buf_ptr;
const uint8_t *ptr = src;
uint8_t *dst = s->buffer;
while (src < buf_end) {
uint8_t x = *(src++);
#define copy_data_segment(skip) do { \
ssize_t length = (ptr - src) - (skip); \
if (length > 0) { \
memcpy(dst, src, length); \
dst += length; \
src = ptr; \
} \
} while (0)
if (s->avctx->codec_id == AV_CODEC_ID_THP) {
ptr = buf_end;
copy_data_segment(0);
} else {
while (ptr < buf_end) {
uint8_t x = *(ptr++);
*(dst++) = x;
if (s->avctx->codec_id != AV_CODEC_ID_THP) {
if (x == 0xff) {
while (src < buf_end && x == 0xff)
x = *(src++);
ssize_t skip = 0;
while (ptr < buf_end && x == 0xff) {
x = *(ptr++);
skip++;
}
if (x >= 0xd0 && x <= 0xd7)
*(dst++) = x;
else if (x)
break;
/* 0xFF, 0xFF, ... */
if (skip > 1) {
copy_data_segment(skip);
/* decrement src as it is equal to ptr after the
* copy_data_segment macro and we might want to
* copy the current value of x later on */
src--;
}
if (x < 0xd0 || x > 0xd7) {
copy_data_segment(1);
if (x)
break;
}
}
}
if (src < ptr)
copy_data_segment(0);
}
#undef copy_data_segment
*unescaped_buf_ptr = s->buffer;
*unescaped_buf_size = dst - s->buffer;
memset(s->buffer + *unescaped_buf_size, 0,