[theora-dev] Bad memory access in libtheora beta3

Maik Merten maikmerten at googlemail.com
Mon Sep 8 04:59:30 PDT 2008

I'm have a similar problem with jheora (also 16x16 video, also in the 
filter code). Perhaps there's some unhandled border-case in all 
implementations. (copy&paste of the original VP3 code?)


ogg.k.ogg.k at googlemail.com schrieb:
> Hi,
> I didn't get to the bottom of it, but Valgrind is whining
> on libtheora when encoding a video to a 16 width or
> 16 height video. While you may think I'm weird for
> encoding to such a size, I didn't care about the output
> video, but I reckon it should work. The bad accesses
> seemed to be of pixel data, in FilterVert__c, and in
> FilterHorz__c (from memory), but I didn't investigate
> more as there wasn't anything obvious after looking for
> a few minutes, and I was busy valgrinding other stuff.
> This was using SVN ffmpeg2theora, which no changes
> that would cause that (famous last words). Command
> line was something like:
> ./ffmpeg2theora -o /tmp/out.ogv --nosound -x 16 -y 16 [irrelevant
> options] foo.ogv
> (yes, from Theora too, I didn't care about the video, the
> --nosound was to prevent ffmpeg2theora from dying due
> to the note below).
> On another note, which you may or may not care
> about, Valgrind also whines for both the Vorbis and
> Theora decoders in ffmpeg (I believe they're both
> custom, though I haven't checked).
> Cheers
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> theora-dev at xiph.org
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