Yes, I was just about to write the same thing, but lpedia beat me to it. I can play audio and video with sound if I switch to OpenSL ES.If not, you probably have the same problem as I came across with some versions of VLC. There's no audio output at all with VLC's default audio output method, AudioTrack. Changing that to OpenSL ES fixed the problem for me.
That setting is in VLC Settings > Extra settings > Audio > Advanced > Audio output.
@Kyrat, For the reboots, send me the zipped file via PM from
mkdir temp cd temp adb root adb pull /data/tombstones # zip the directory above
No guarantees that I will find or solve the problem. In addition, it could be an application that you are using that causes the reboots. The tombstones will have the information.