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Code Issues Releases Activity

lavf/icodec: Improve autodetection.

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Avoids misdetection of MPEG (B-)frames.

Reviewed-by: Michael Bradshaw
This commit is contained in:
Carl Eugen Hoyos 2016-01-18 00:36:44 +01:00
parent f59b727e2f
commit 9bc281beae
1 changed files with 25 additions and 3 deletions
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28
libavformat/icodec.c
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@ -27,6 +27,7 @@
#include "libavutil/intreadwrite.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/bmp.h"
#include "libavcodec/png.h"
#include "avformat.h"
#include "internal.h"
@ -44,9 +45,30 @@ typedef struct {
static int probe(AVProbeData *p)
{
if (AV_RL16(p->buf) == 0 && AV_RL16(p->buf + 2) == 1 && AV_RL16(p->buf + 4))
return AVPROBE_SCORE_MAX / 4;
return 0;
unsigned i, frames = AV_RL16(p->buf + 4);
if (AV_RL16(p->buf) || AV_RL16(p->buf + 2) != 1 || !frames)
return 0;
for (i = 0; i < frames; i++) {
unsigned offset;
if (AV_RL16(p->buf + 10 + i * 16) & ~1)
return FFMIN(i, AVPROBE_SCORE_MAX / 4);
if (p->buf[13 + i * 16])
return FFMIN(i, AVPROBE_SCORE_MAX / 4);
if (AV_RL32(p->buf + 14 + i * 16) < 40)
return FFMIN(i, AVPROBE_SCORE_MAX / 4);
offset = AV_RL32(p->buf + 18 + i * 16);
if (offset < 22)
return FFMIN(i, AVPROBE_SCORE_MAX / 4);
if (offset + 8 > p->buf_size)
return AVPROBE_SCORE_MAX / 4 + FFMIN(i, 1);
if (p->buf[offset] != 40 && AV_RB64(p->buf + offset) != PNGSIG)
return FFMIN(i, AVPROBE_SCORE_MAX / 4);
if (i * 16 + 6 > p->buf_size)
return AVPROBE_SCORE_MAX / 4 + FFMIN(i, 1);
}
return AVPROBE_SCORE_MAX / 2 + 1;
}
static int read_header(AVFormatContext *s)