[ogg-dev] validator.annodex.org

[Ian Malone]

Conrad Parker wrote:
> On Thu, Feb 16, 2006 at 03:25:07PM +0000, Ian Malone wrote:
> 
>>(You really don't want to know this I'm sure)
>>I gave this a go this morning on the samples from
>><http://wiki.xiph.org/index.php/Metadata>, which
>>are there mainly for the purpose of breaking things.
>>They don't validate (which neither surprises nor upsets
>>me), but I downloaded the oggz source and built oggz-validate
>>to find out why and discovered that it segfaults, which it
>>probably shouldn't (I didn't have time to look into the cause).
>>As far as I know they are valid ogg bitstreams (ogginfo passes
>>them okay), even if the contents aren't proper media types.
> 
> 
> ok, I did know that oggz-validate only passes things which are known
> media types (currently it knows about Vorbis, Theora, Speex, Flac, CMML,
> OggPCM(draft2) and Skeleton). I guess this is because the original
> reason for oggz-validate was to check interleaving order, for which it
> needs to be able to interpret granulepos. It's probably worth adding an
> option to disable those checks and only check the bitstream packing.
> 
> 

I think it's simpler than that:
/src/tools/oggz-validate.c
Line 176, the return value of ot_page_identify is not checked before
being handed to strcmp.

Inserting a check for a valid pointer seems to fix it, the multi-xml
packet streams then give a string of:
00:00:00.002: serialno 1044457395: Packet out of order (previous 
00:00:00.944)
errors, which is as it should be since the granulepos of the xml
packets is nonsensical. (Monotonically increasing, but nonsensical,
the aim of those streams is testing that applications can ignore them
for seeking.)

-- 
imalone