[LAD] resampling with sp/dif

Conrad Berhörster conrad.berhoerster at gmx.de
Mon Apr 19 16:12:59 UTC 2010

Hello Joshua, 

Am Montag 19 April 2010 17:07:35 schrieb Joshua Boyd:
> On Mon, Apr 19, 2010 at 12:38:35PM +0200, Conrad Berh?rster wrote:
> > Hello,
> >
> > i want to grab some external sources (cdplayer)  with jack. i run a jack
> > instance with 48000 Hz and it works perfectly with my cd player and
> > ardour. but if i take a cheaper cdplayer, the signal will only be came in
> > with 44100,  because there seems no resample and sync between the master
> > (soundcard) and  slave (cheapoCD) . so, the signal will always being
> > played to slow. i found a  workaround with a small external box, which
> > resamples the incoming signal  before it get into the soundcard.
> Your spdif sound card might have a sample rate converter.  If it did,
> most likely the work flow would be to set jack at 48k and then just play
> normally and the sound card would convert from the incoming 44.1k to the
> 48k it is set to.  The SRC chip in your sound card (again, presuming it
> has one, which I think is likely) is probably similar to whatever is in
> the external box you've tried.

i own a gina 3G. i don't think, it has such a chip.  anyway,  never had heard, 
how to obtain an extra SRC Chip on any soundcard. has  ALSA/Jack the 
possibilty to do such a thing? 

As i have read today, Spdif seems close to AES/EBU, which doesn't sent sample 
rate information. so, there seems to be different implementations in different 
Players. Some are better, some not. So, i have no chance to check that in any 
way except hearing. hmm.

> Unless there is a real need to do this in realtime, say for a live
> performance, 
What a pity, i need it in realtime. ;=(
i  have written a software, which mixes some files. and now i want to add the 
possibility to add external sources like a CD Player. 

but thanks for your thoughts 
sizu c~

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