[Alsa-user] Noise when switching from PCM to AC3 streams

[Marcus Agehall]

Hi!

I'm trying to use the optical S/PDIF out on my Abit KN8-Ultra motherboard (nForce4 based).
I've managed to set things up so that I can play PCM data and AC3 data using my Sony STR-925 receiver. The only problem left, is that when I start playing an AC3 stream, after playing PCM data, the receiver plays some very loud and disturbing noise the before recognizing the AC3 stream and switching to AC3 mode.

After some serious googling I'm suspecting that, for some strange reason, the status bits on the S/PDIF interface are not changed correctly at the correct time, which causes AC3 data to be interpreted as PCM.  However, I've not been able to verify that this is the case.

Has anyone else had this problem and prehaps found a solution to it?