I see. AVI is not generally considered a streaming format. I’m not real savvy about IPTV per se, but from a streaming perspective, you’re going to have to get your bit rates down to something your network can manage. I suspect this is one reason you may be losing A/V sync. Surely Cisco’s product has a manual with recommendations and a best practices section? At a guess, I’d think you’d be looking to export some kind of mpeg format, or possibly M-JPEG.
Regardless, your bigger problem is not knowing how to change export settings, or possibly having a corrupt Avid install. In the settings window of your Avid, click the “hamburger” menu (bar-shaped button left of your name) and make sure “All Settings” is checked. This should show you a variety of preset export settings. If you don’t see that, it’s time to contact your friendly Avid dealer. Know that you can change these settings. I suspect you’re only seeing the Base Settings or Selected Settings, which may explain why AVI seems to be the only available format. Double-clicking on the word “Export” by a setting will allow you to customise that setting. Give it a whirl!