[FFmpeg-devel] [PATCH]lavf/mxfdec: Limit score for strangely cut files

[Tomas Härdin]

mån 2020-08-24 klockan 21:42 +0200 skrev Carl Eugen Hoyos:
> Hi!
> 
> Attached patch fixes ticket #8846, the sample there is both a mov and
> an mxf file.
> It is not entirely clear to me if the sample was only made to annoy us
> but the content looks real.
> 
> An alternative may be to check the extension if the score is equal but
> I don't really like that either.

The file is a polyglot, yes. The run-in feature in MXF exists to be
able to add extra metadata and other MXF features while maintaining
backward compatibility. And to be annoying.

> Subject: [PATCH] lavf/mxfdec: Limit score for strangely cut files.

I'd reword this to "lavf/mxfdec: Limit score for files with run-in"

> @@ -3615,7 +3615,7 @@ static int mxf_probe(const AVProbeData *p) {
>                  AV_RN32(bufp+ 4) == AV_RN32(mxf_header_partition_pack_key+ 4) &&
>                  AV_RN32(bufp+ 8) == AV_RN32(mxf_header_partition_pack_key+ 8) &&
>                  AV_RN16(bufp+12) == AV_RN16(mxf_header_partition_pack_key+12))
> -                return AVPROBE_SCORE_MAX;
> +                return bufp - p->buf ? AVPROBE_SCORE_MAX - 1 : AVPROBE_SCORE_MAX;

bufp != p->buf would be more readable. Else this does the same thing as
a patch I was just working on, so the logic is OK.

/Tomas