Subject: Re: [linux-audio-dev] syncing soundcards
From: depet_AT_gmx.de
Date: Thu Mar 16 2000 - 12:03:28 EST
has this issue been continued private?
I can't find the messages you are replying to.
On 16-Mar-2000 Iain Sandoe wrote:
>> On Sun, 12 Mar 2000, Iain Sandoe wrote:
>>> You also have to be aware that they will *probably* not end up phase-synced
>>> (as they would if you had a W-CLK) - because there might be several steps
>>> between oscillator & sampling - which could be different on the two cards.
>>> -- of course 2 off the same model, same version, same issue should be OK :)
>>
>> Then again, unless the drivers start the two cards at the same time
>> (within less than a sample period), you'll get an additional phase
>> error. You probably will get the cards within a sample or two, but
>> you might have to use RTLinux + hacked driver to get beyond that. It
>> might be possible, but personally, I don't think it seems to be worth
>> the effort, unless it's for some system that is to go into mass
>> production...
>
> My comment was really aimed at the sub-sample issues.
>
> I would hope (sincerely) that the linux sound implementation would aim to
> allow multiple cards (with differing latencies ;) to be accommodated
>
> I realise that this is quite hard (and therefore fun :)...
>
> once (in the big, bad, closed-source commercial world) we had to sync up
> eight cards - all with on-board dsp... to solve a real problem. For many
> people several inexpensive cards (although I would hope with W-CLK at least)
> - is a much better option than one biggie $$$ super-whizzbang.
>
> one of the main limitations of the V** system at present is that it doesn't
> (yet?) allow this.
>
> perhaps this is really for PBD/et. al's discussion on stop/start issues
> related to cards/channels.
>
> Iain.
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