[FFmpeg-devel] [PATCH] Don't read out-of-bounds values for vc1

Kostya kostya.shishkov
Wed Jun 3 06:38:34 CEST 2009

On Tue, Jun 02, 2009 at 03:06:45PM -0700, Eli Chen wrote:
> I've encountered an out of bounds read seg fault in the vc1 codec
> Apparently there were some fixes in other codecs, but wasn't applied to
> vc1.  Please see attached patch.

It can be fixed differently - by changing edge condition in vc1.c
motion compensation (vc1_mc_1mv() or vc1_mc_4mv_chroma())

Also how does this affect speed? 
> ==18859== Invalid read of size 1
> ==18859== at 0x4272F36: put_no_rnd_vc1_chroma_mc8_c (dsputil.c:1693)
> ==18859== Address 0x9208950 is 0 bytes after a block of size 230,416 alloc'd
> ==18859== at 0x4021D52: memalign (vg_replace_malloc.c:460)
> ==18859== by 0x466D5A0: av_malloc (mem.c:61)
> Regards,
> Eli Chen

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