[LAU] Recording from S/PDIF

[David Kastrup]

Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw at public.gmane.org>
writes:

> David Kastrup wrote:
>> I have a Minidisc deck with various digital in- and outputs using
>> S/PDIF.  If you connect another MD deck or a CD player digitally and
>> record from it, it will faithfully reproduce the titling (not sure about
>> alphanumeric titles, but at least the starting points of the tracks will
>> be accurate and reliable and not just based on pauses like when
>> recording via the analog inputs).
>
> It's possible that these sourcees send invalid or different data during
> the pauses between tracks.

I think it works even with track marks on continuous play.  Not sure
about it, though.  I need to check whether I have any CDs of that kind:
my digital-output CD player is too old to deal with any self-written
CDs.  Assuming that its belts are still in working order.

>> Now how do I get this information when recording an S/PDIF signal
>> into the computer?
>
> If that information is present, it must be in the channel status bits.
>
>> Does this information get back out of the ALSA driver (I can use
>> an RME Multiface here) in some manner?
>
> As far as I can see, this driver does not give you access to the
> channel status bits of the capture stream.  (And even C-Media cards
> give you only the first 32 bits.)

Huh.  Is that an ALSA shortcoming?  It would seem like something worth
unifying over several drivers capable of S/PDIF.  Oh, and what's the
deal with Dolby Surround via S/PDIF?  That would also need some sort of
access different to PCM, wouldn't it?

-- 
David Kastrup