KVIA is multilingual, so they have 2 audio tracks English, an Spanish. Maybe you have it set to Spanish and that's why there's no audio.
It is just a few commercials once in a while, and the same commercial maybe in english the next time. Everything else is in english. Not a big problem for me personally since I would rather not hear the commercials anyway.
Anyone have trouble with KTSM channel 9 audio being very loud on local and network programs? I run all the other local stations around 32-34 on my home theater but on KTSM I have to turn it down to 22-23.