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avformat/dv: about 3 times faster probe

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-11-09 14:43:51 +01:00
parent dbb41f93c1
commit 76a47d66c4
1 changed files with 15 additions and 13 deletions
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14
libavformat/dv.c
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@ -590,19 +590,21 @@ static int dv_probe(AVProbeData *p)
if (p->buf_size < 5) if (p->buf_size < 5)
return 0; return 0;
state = AV_RB32(p->buf); for (i = 0; i < p->buf_size-4; i++) {
for (i = 4; i < p->buf_size; i++) { unsigned state = AV_RB32(p->buf+i);
if ((state & 0xffffff7f) == 0x1f07003f) if ((state & 0x0007f840) == 0x00070000) {
matches++;
// any section header, also with seq/chan num != 0, // any section header, also with seq/chan num != 0,
// should appear around every 12000 bytes, at least 10 per frame // should appear around every 12000 bytes, at least 10 per frame
if ((state & 0xff07ff7f) == 0x1f07003f) if ((state & 0xff07ff7f) == 0x1f07003f) {
secondary_matches++; secondary_matches++;
if ((state & 0xffffff7f) == 0x1f07003f)
matches++;
}
if (state == 0x003f0700 || state == 0xff3f0700) if (state == 0x003f0700 || state == 0xff3f0700)
marker_pos = i; marker_pos = i;
if (state == 0xff3f0701 && i - marker_pos == 80) if (state == 0xff3f0701 && i - marker_pos == 80)
matches++; matches++;
state = (state << 8) | p->buf[i]; }
} }
if (matches && p->buf_size / matches < 1024 * 1024) { if (matches && p->buf_size / matches < 1024 * 1024) {