I've been trying to watch some mp4 videos I've run into a problem, there are no voices. There's sound, music, background noises, even background voices, but the voices of the on-screen characters are silent.
I've tried it on windows media player as well as VLC with the same results. It seems like it might be related to the videos being configured for surround sound and I'm watching them on my laptop with headphones, but I'm not sure where to go to fix it.
Use this : http://cccp-project.net/
What codec are you using for video playback? FFmpeg (part of the FFDShow pack) in particular comes to mind as having known stability issues. From personal experience, XviD's also occasionally destabilizes.
I've had that happen with VLC sometimes but always went away when I rebooted.