Subject: Re: [linux-audio-dev] time stretching and compression under Linux ?
From: David Gerard Matthews Jr. (dgm4+@pitt.edu)
Date: Mon Nov 12 2001 - 05:24:35 EET
greetings,
As the not-so-proud owner of an SBLive card, I thought I'd chime in.
Your project sounds really cool, and I'm all in favor of highly
unorthodox ideas. I'd be very interested in hearing the result, and if
you do write some code, I'd love to see it. But please, do yourself a
favor and stay away from the SBLive series! As I said, I have one
myself, and I've never really been happy with it. It's got a high noise
floor, and forget trying to do any decent recording/live processing on
the analogue inputs. (The converters leave a little something to be
desired.) As far as synching multiple cards, good luck. There's no
word clock, so you'd have to do everything at the interrupt level, (I
think), and while I'm no low-level hacker that sounds pretty hairy to
me. For the price of two SB's, you could get yourself an M-Audio Delta
series. (At least you can in the US; I imagine that M Audio's cards are
actually cheaper in the U.K. since they're a British company.) May I
also mention that alsa support for the SBLive sucks?
Just throwing in my $0.02.
Good Luck,
dgm
motet_AT_zoom.co.uk wrote:
>
> hi again
>
> >i've said this many times before, but i think you're making
> >a serious error even attempting this.
>
> maybe we are
> ... or maybe we're just working on building something rather
> unorthodox and curious... ;)
>
> there's no problems with finding a programmer or spending
> time on coding... perhaps i should have mentioned before
> that the person doing the coding will be the person building
> the machine, so that isnt a problem :).
>
> what i guess we're wanting to do is something quite
> experimental, we dont have any other facilities (otherwise
> we probably would just go out and buy a 4 input card :). its
> one of those quirky no-budget projects that linux seems to
> thrive on...
> we're also well aware that its going to be difficult, and
> not exactly perfect. but that's half the fun... ;)
>
> i decided to post here just because i'm curious to see if
> there does happen to be any source code about for synching
> multiple inputs. i think our project could well be an
> interesting development. if we happen to come up with
> something that is practicable... then it might well be
> useful to the linux-audio community too...
>
> yes, i would much prefer to just have the facilities to go
> out and buy a high-spec card... but i wonder how many other
> people are running multiple low-spec soundcards under linux
> (i already am) and could use them for synching 4+ inputs?
>
> the idea we've had so far, is to get some form of spread
> spectrum generator, and create a small sync pattern encoded
> into the four inputs, using a spread spectrum card, with the
> frequency shifted down to 48k or something. then after
> recording 4 inputs, running something to stretch and
> compress each signal to the original time base that was
> externally generated.
>
> but, if there's already software or source code being worked
> on to do this sort of thing - or to correct synch in
> multiple inputs by any other means - then we'd be very
> grateful to know about it, so we won't end up having to
> reinvent the wheel.
>
> yes, its weird, and its unorthodox.. but it might just work ;)
>
> cheers
>
> miriam
>
> mrainsford_AT_mstation.org
>
> Get your own zoom email - click here - http://www.zoom.co.uk/
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