Subject: Re: [linux-audio-dev] [OT] Can RME HDSP Multiface be used for 5.1 Dolby or 7.1 Dolby Surround output?
From: Paul Davis (pbd_AT_op.net)
Date: Mon Apr 29 2002 - 15:29:20 EEST
>I, however did find something regarding AC-3 stuff in the Multiface
>manual, but am not sure as to what does it exactly refer to. The whole
>pdf file can be found here:
[ ... ]
>This 'SPDIF' signal sounds like chopped noise at highest level.
>Therefore check 'Non-audio' in
>the card's Settings dialog, to prevent most SPDIF receivers from
>accepting the signal, and to
>prevent any attached equipment from being damaged.
You can do this easily with ALSA. Its just one of the standard IEC958
bits that can be set with alsactl, amixer or set. You'll have to ask
on alsa-devel what to set, since the Hammerfall driver shares generic
ALSA code to set these bits, and I don't know how this is
designed. There are several IEC958-related switches, and one of them
contains the relevant bits for this task.
However, I have no idea how you would deliver AC-3 to the S/PDIF
channels. Presumably, AC-3 is a stereo (or more precisely, 2 channel)
encoding of a multichannel signal, and thus its first packaged into a
2 channel form and just written to the channels. Right?
--p
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