[FFmpeg-cvslog] omadec: loosen format probing constraints

[David Goldwich]

ffmpeg | branch: master | David Goldwich <david.goldwich at gmail.com> | Thu Oct 24 15:24:26 2013 +0200| [0a7fef39fc578bd7c90fd2646299f8cad722ecb1] | committer: Anton Khirnov

omadec: loosen format probing constraints

Imporoves detection of some files in the wild:

- ID3v2 a.k.a. "ea3" header is optional.
- Version and flags in ID3v2 header are unspecified.

Signed-off-by: David Goldwich <david.goldwich at gmail.com>
Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0a7fef39fc578bd7c90fd2646299f8cad722ecb1
---

 libavformat/omadec.c |   15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/libavformat/omadec.c b/libavformat/omadec.c
index eeab70e..709a60b 100644
--- a/libavformat/omadec.c
+++ b/libavformat/omadec.c
@@ -446,23 +446,16 @@ static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
 
 static int oma_read_probe(AVProbeData *p)
 {
-    const uint8_t *buf;
+    const uint8_t *buf = p->buf;
     unsigned tag_len = 0;
 
-    buf = p->buf;
-
-    if (p->buf_size < ID3v2_HEADER_SIZE ||
-        !ff_id3v2_match(buf, ID3v2_EA3_MAGIC) ||
-        buf[3] != 3 || // version must be 3
-        buf[4]) // flags byte zero
-        return 0;
-
-    tag_len = ff_id3v2_tag_len(buf);
+    if (p->buf_size >= ID3v2_HEADER_SIZE && ff_id3v2_match(buf, ID3v2_EA3_MAGIC))
+        tag_len = ff_id3v2_tag_len(buf);
 
     /* This check cannot overflow as tag_len has at most 28 bits */
     if (p->buf_size < tag_len + 5)
         /* EA3 header comes late, might be outside of the probe buffer */
-        return AVPROBE_SCORE_EXTENSION;
+        return tag_len ? AVPROBE_SCORE_EXTENSION : 0;
 
     buf += tag_len;