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Fix mjpeg-b (padding bytes can exist between end of sos and image data)

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Originally committed as revision 3653 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Roberto Togni 2004-10-29 20:45:47 +00:00
parent ae2ade6bbd
commit 9287acd197
1 changed files with 11 additions and 3 deletions
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14
libavcodec/mjpeg.c
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@ -837,6 +837,8 @@ typedef struct MJpegDecodeContext {
int buggy_avid;
int interlace_polarity;
int mjpb_skiptosod;
} MJpegDecodeContext;
static int mjpeg_decode_dht(MJpegDecodeContext *s);
@ -1517,6 +1519,10 @@ static int mjpeg_decode_sos(MJpegDecodeContext *s)
if(s->avctx->debug & FF_DEBUG_PICT_INFO)
av_log(s->avctx, AV_LOG_DEBUG, "%s %s p:%d >>:%d\n", s->lossless ? "lossless" : "sequencial DCT", s->rgb ? "RGB" : "", predictor, point_transform);
/* mjpeg-b can have padding bytes between sos and image data, skip them */
for (i = s->mjpb_skiptosod; i > 0; i--)
skip_bits(&s->gb, 8);
if(s->lossless){
if(s->rgb){
if(ljpeg_decode_rgb_scan(s, predictor, point_transform) < 0)
@ -1962,7 +1968,7 @@ static int mjpegb_decode_frame(AVCodecContext *avctx,
AVFrame *picture = data;
GetBitContext hgb; /* for the header */
uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
uint32_t field_size;
uint32_t field_size, sod_offs;
/* no supplementary picture */
if (buf_size == 0)
@ -1974,6 +1980,7 @@ static int mjpegb_decode_frame(AVCodecContext *avctx,
read_header:
/* reset on every SOI */
s->restart_interval = 0;
s->mjpb_skiptosod = 0;
init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
@ -2023,16 +2030,17 @@ read_header:
sos_offs = get_bits_long(&hgb, 32);
dprintf("sos offs: 0x%x\n", sos_offs);
sod_offs = get_bits_long(&hgb, 32);
dprintf("sod offs: 0x%x\n", sod_offs);
if (sos_offs)
{
// init_get_bits(&s->gb, buf+sos_offs, (buf_end - (buf+sos_offs))*8);
init_get_bits(&s->gb, buf+sos_offs, field_size*8);
s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
s->start_code = SOS;
mjpeg_decode_sos(s);
}
skip_bits(&hgb, 32); /* start of data offset */
if (s->interlaced) {
s->bottom_field ^= 1;
/* if not bottom field, do not output image yet */