[FFmpeg-devel] [HACK] fix issue 944

[Michael Niedermayer]

On Fri, Apr 10, 2009 at 01:24:33PM +0200, Reimar D?ffinger wrote:
> Hello,
> the file in issue 944 causes mb_xy to become something around -300 and
> then crashes.
> Attached patch fixes this the brute-force way, for a better fix I'd need
> hints where to look.

> Index: libavcodec/h264.c
> ===================================================================
> --- libavcodec/h264.c	(revision 18407)
> +++ libavcodec/h264.c	(working copy)
> @@ -1005,6 +1005,7 @@
>          }else if(!(s->picture_structure & h->ref_list[1][0].reference) && !h->ref_list[1][0].mbaff){// FL -> FL & differ parity
>              int fieldoff= 2*(h->ref_list[1][0].reference)-3;
>              mb_xy += s->mb_stride*fieldoff;
> +            mb_xy = FFMAX(mb_xy, 0);

how does it become -300 ?
reference should never become anything outside 0..7
am i right in the assumtation that reference is outside that range?

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Avoid a single point of failure, be that a person or equipment.
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