[LAU] Recording from S/PDIF

David Kastrup dak at gnu.org
Thu Nov 23 08:31:42 UTC 2017


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

> David Kastrup wrote:
>> Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw at public.gmane.org>
>> writes:
>>> Paul Davis wrote:
>>>> When I wrote the RME driver for the digiface/multiface/digi9652 etc, I
>>>> knew that status bits were available, but I don't recall exporting them
>>>> to user space. At this point in time, I don't even remember what the
>>>> ALSA abstraction for that would be. The "control" device? The mixer?​
>>>
>>> Mixer control "IEC958 Capture Default"/"... Mask".
>>
>> Huh.  This begs the question: are there any applications making use of
>> it?
>
> I am not aware of any.
>
>> For example, for recording via S/PDIF including track marks?
>
> Further research shows that the track number is not transmitted in the
> channel status bits but in the "user"/"subcode" bits.  I have never seen
> any sound card that allows access to those.

Pfffft.  Well, it would explain why there are no programs making use of
it.  Basically my option would then be to acquire an audio CD recorder
with digital input and record the minidiscs (copy protection bit
permitting) to CD from which I use cdparanoia et al to get the full
information.  Possibly putting the Hammerfall as pass-through in the
middle, hoping that it will pass on the user/subcode bits while clamping
down on copy protection.  Yes, that sounds overoptimistic: there is no
obvious reason why anything but PCM data should make it through its
Totalmix.

Or I hope that recording a copyright-bit plagued Minidisc will at least
record _structured_ silence.  In which case I can at least get the
structure on CD.

This is all rather icky.  Does anybody using other operating systems
know whether the situation is basically the same there?

-- 
David Kastrup


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