VLC team last week released their beta version of Windows Phone app in Store. Many users reported about lots of audio related issues. In fact, I was not able to play any audio on my Lumia 920 devices running WP8.1 developer preview. Today, VLC team released an update to the beta app which fixes this issue. I can now play video and audio without any issues on my device. The following version is now available in Windows Phone Store.
You can update the app here from Windows Phone Store.