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nsv: simplify probe function

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This commit is contained in:
Aurelien Jacobs 2011-06-13 18:30:55 +02:00
parent 223694b404
commit eb8de45c3c
1 changed files with 10 additions and 16 deletions
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26
libavformat/nsvdec.c
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@ -21,6 +21,7 @@
#include "avformat.h"
#include "riff.h"
#include "libavutil/dict.h"
#include "libavutil/intreadwrite.h"
//#define DEBUG_DUMP_INDEX // XXX dumbdriving-271.nsv breaks with it commented!!
#define CHECK_SUBSEQUENT_NSVS
@ -736,10 +737,8 @@ static int nsv_read_close(AVFormatContext *s)
static int nsv_probe(AVProbeData *p)
{
int i;
int score;
int vsize, asize, auxcount;
score = 0;
int i, score = 0;
av_dlog(NULL, "nsv_probe(), buf_size %d\n", p->buf_size);
/* check file header */
/* streamed files might not have any header */
@ -751,19 +750,14 @@ static int nsv_probe(AVProbeData *p)
/* seems the servers don't bother starting clean chunks... */
/* 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') {
score = AVPROBE_SCORE_MAX/5;
if (AV_RL32(p->buf + i) == AV_RL32("NSVs")) {
/* 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;
}
int vsize = AV_RL24(p->buf+i+19) >> 4;
int asize = AV_RL16(p->buf+i+22);
int offset = i + 23 + asize + vsize + 1;
if (offset <= p->buf_size - 2 && AV_RL16(p->buf + offset) == 0xBEEF)
return 4*AVPROBE_SCORE_MAX/5;
score = AVPROBE_SCORE_MAX/5;
}
}
/* so we'll have more luck on extension... */