[Jack-Devel] Does alsa_in reading from SPDIF input inject pops and clicks?

[Chris Caudle]

On Thu, August 8, 2019 6:46 pm, crocket wrote:
> * Does clock source matter if alsa_in resamples every audio sample to jack
> server's clock?

Yes, because the audio data has to be transferred through the audio
hardware and into the system memory without error before alsa_in (or
preferrably zita_alsa2jack) can resample to the jack clock.  If your audio
interface is running from an internal clock source but attempting to read
data from S/PDIF there will be an error whenever the internal clock edge
is not lined up with the proper time in the S/PDIF data stream.  There is
a way around that (essentially real time sample rate conversion in the
hardware similar to what alsa_in does), but it adds cost so is rarely
used.

> Is it impossible to extract audio sample without knowing clock?

Yes, clock management is a fundamental part of digital audio.

> * How can I have my computer automatically switch clock source between
> SPDIF and internal?

I am not aware of a general way.

-- 
Chris Caudle