Per Toft wrote: > Lee Revell wrote: >> On 5/21/07, Per Toft <per@xxxxxxxxxx> wrote: >>> Hi! >>> >>> I have huge problems enabling surround on a VIA VT1617A sound card using >>> the ALSA via82xx module. >>> >>> The problem is that i have sound on the front left & right speaker, but >>> nothing on the others (center and rear). The problem is the same when im >>> using analog smart 5.1 (3 mini jacks) or S/PDIF Coax digital out. >>> >>> e.g. when i run: >>> speaker-test -Dplug:iec958 -c6 >>> i hear sound in the two front speakers and nothing i the others. >> This can't work because SPDIF only supports two channels. >> >> What happens when you try "speaker-test -Dplug:surround51 -c6"? >> >> Lee > Hi Lee, > > S/PDIF is digital output and i support more than two channels. My > decoder supports Dolby Digital and DTS and it works perfectly under windows. > > When i run: > speaker-test -Dplug:surround51 -c6 > i get output in two channels (front left/right). > > > Per S/PDIF supports either two PCM (uncompressed) channels or passthrough of lossily encoded multichannel (up to 8 channels can be used then afaik). speaker-test, as you tried to run it, is generating 6 PCM (uncompressed) streams, and as S/PDIF can only carry 2 PCM channels then you only near two of them out of your speakers. "Dolby Digital" and DTS are both lossy (some audio quality is lost to save filesize/bandwith) formats which Windows, and probably ALSA, can pass directly over the digital link to be decoded by your speakers' decoder. The things which *should* work for multichannel are: * Enabling digital passthrough and sending undecoded AC3/DTS straight to your reciever * Using 3 (analogue) stereo cables to connect your PC to your speakers, you'll then need to use the surroundXX family of devices. Probably surround51 -ol
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