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nsv: Fix misdetection of MP3 files as NSV.

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If an MP3 file contains the string NSVs, the NSV probe will confuse it for an
NSV file. Check for 0xBEEF after a Video/Audio chunk to achieve more accuracy.

Signed-off-by: Diego Biurrun <diego@biurrun.de>
This commit is contained in:
Thierry Foucu 2011-05-11 21:27:04 -07:00 committed by Diego Biurrun
parent b3bbc6fdc5
commit 45faf7fcd3
1 changed files with 17 additions and 3 deletions
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20
libavformat/nsvdec.c
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@ -737,6 +737,9 @@ static int nsv_read_close(AVFormatContext *s)
static int nsv_probe(AVProbeData *p)
{
int i;
int score;
int vsize, asize, auxcount;
score = 0;
av_dlog(NULL, "nsv_probe(), buf_size %d\n", p->buf_size);
/* check file header */
/* streamed files might not have any header */
@ -749,14 +752,25 @@ static int nsv_probe(AVProbeData *p)
/* sometimes even the first header is at 9KB or something :^) */
for (i = 1; i < p->buf_size - 3; i++) {
if (p->buf[i+0] == 'N' && p->buf[i+1] == 'S' &&
p->buf[i+2] == 'V' && p->buf[i+3] == 's')
return AVPROBE_SCORE_MAX-20;
p->buf[i+2] == 'V' && p->buf[i+3] == 's') {
score = AVPROBE_SCORE_MAX/5;
/* Get the chunk size and check if at the end we are getting 0xBEEF */
auxcount = p->buf[i+19];
vsize = p->buf[i+20] | p->buf[i+21] << 8;
asize = p->buf[i+22] | p->buf[i+23] << 8;
vsize = (vsize << 4) | (auxcount >> 4);
if ((asize + vsize + i + 23) < p->buf_size - 2) {
if (p->buf[i+23+asize+vsize+1] == 0xEF &&
p->buf[i+23+asize+vsize+2] == 0xBE)
return AVPROBE_SCORE_MAX-20;
}
}
}
/* so we'll have more luck on extension... */
if (av_match_ext(p->filename, "nsv"))
return AVPROBE_SCORE_MAX/2;
/* FIXME: add mime-type check */
return 0;
return score;
}
AVInputFormat ff_nsv_demuxer = {