theora dev - Sep 2008 - Bad memory access in libtheora beta3

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

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?)

Maik

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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