[LAU] Recording from S/PDIF

[Len Ovens]

On Wed, 22 Nov 2017, David Kastrup wrote:

>> 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).
>
> 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?

I know on my ice1712 based D66 it is an interface shortcoming. From what I 
can see of s/pdif chip sets the user info is a separate stream that most 
interfaces just leave NC. The PCM stream itself does not have anymore info 
than an ADC would give (it is the same connection). So the first thing you 
need to do is make sure that the user info actually makes it to the 
computer with your card. The D66 (and 1010) does deal with some of these 
extra bits (consumer/pro, emph, etc.) but not all... but then it is not a 
"profesional" interface. I know broadcast makes use of extra bits and so I 
would expect interfaces made for that world to pass them through. I would 
check with your card if there is any SW/drivers in the mac/win world that 
deals with extra info.

--
Len Ovens
www.ovenwerks.net