[Ffmpeg-devel] Possible bug in h264 dec

Francis Labonte francis_labonte
Thu Sep 29 05:09:03 CEST 2005


Runnning valgrind on a file, I got some invlid read.

It points to:
   H264_CHROMA_MC8_TMPL in dsputil_h264_template_mmx.c called by
   mc_dir_part in h264.c

In my opinion, I think it could come from here:

    if(   full_mx < 0-extra_width
       || full_my < 0-extra_height
       || full_mx + 16/*FIXME*/ > pic_width + extra_width
       || full_my + 16/*FIXME*/ > pic_height + extra_height)

"<" should become "<=" for the 2 FIXME.  An index ( mx, my) ranging from 
0-... is compared to a size ranging from 1-,,,

Applying my modification fix my invalid.

I would like to have have some  input  to know if my analysis make sens or 

Thank you

NOTE: I'me not using the latest version of CVS, but this line didn't change 
in HEAD, and a friend told me he got similar result with HEAD version.

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