Is Cowon violating the GPL?

[Phanton_13]

I recently bought a IAUDIO player, and wen I installed the JetAudio for the video conversion ( I am not able to encode it with virtualdub, I ned to find the correct configuration ), wen I was ging to investigate the program to view if I can find the configuration betwen their files, I saw thet they were using a custon XVID pluging in a dll files, and I can't find any source in internet, CD or the HD for the program or the pluging. If is XVID a GPL software then, is COWON is violating the GPL?

[celtic_druid]

Is it custom or just xvidcore.dll?

[sysKin]

Is it custom or just xvidcore.dll?
This doesn't matter for GPL.

[shevegen]

Seems to be a bit similar to how Sigma Designs Inc went on, using Xvid but refused to remove it. (They said they will remove it, they did not.)
If IAUDIO altered the source of xvid, and publish it like how they seemed to do, they need to release the modified version publicly.