Zune PC - Xbox Software cant see some avi's
I've downloaded, installed and set up the Zune streaming to Xbox software, and it works brilliantly! I can stream my avi collection finally to my xbox from upstairs!
However... My list of Avi's to play is considerably shorter than my actual folder contains, and I cant work out why. I have compared files that can be viewed with those that cant, and I cant see a difference. They are both Xvids for example, using the same xvid en-code codex, they are similar file sizes, they use the same naming convention, they both end in AVI, and their sound files are both AAC.
And yet one shows up when streaming and one doesnt. If I move the one that it cant see to its own folder, and I open that, it still cant see it (it says "No Video Files found").
The only thing I have managed to work so far is converting these avi's to another format (Mp4) but it takes an hour per file.
Does anyone know what might be going on?
edit: p.s. - These files that zune cant see will play on the xbox perfectly when on a usb key.
Edit - I've noticed the ones that dont play have AC3 audio.. but it cant be that as the problem, can it? Surely it would still show the video files in the list and then just play them silently, not completely remove them from the selection.