Re: [linux-audio-dev] Lots about latency and disk i/o and JACK...<g>

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Subject: Re: [linux-audio-dev] Lots about latency and disk i/o and JACK...
From: Paul Winkler (slinkp23_AT_yahoo.com)
Date: Thu Oct 04 2001 - 03:24:40 EEST


On Wed, Oct 03, 2001 at 01:53:53PM -0700, John Lazzaro wrote:
> It took around 3 weeks of design and coding to set sfront up to handle
> audio drivers that used callbacks -- so for some sorts of applications,
> at least, its a pretty straightforward retrofit. The sfront changes were
> done in preparation for Portaudio (now in sfront 0.75) and CoreAudio
> primarily, but hopefully JACK support will happen too, especially if
> someone is interested enough to write an sfront audio driver and
> contribute it.

Cool! Do you think it might be possible to write a LADSPA driver so
that it would be possible to write LADSPA plugins in SAOL? I looked
into this a while ago but I didn't get very far - I'm really not a C
programmer so I get stuck on pretty simple things.

The main thing I couldn't figure out was how to deal with control
ports. If I understand LADSPA, the control ports of a LADSPA plugin
only get one value per block of audio data, and the host - not the
plugin - determines the blocksize. To borrow Csound terminology which
(I think) SAOL shares, the blocksize corresponds to ksmps.

But I believe that in SAOL, the SAOL orchestra wants to specify its
own ksmps. So that would be an obstacle to compiling a LADSPA plugin
from SAOL.

Is this understanding correct? If so, is there any way to modify SAOL
so that a compiled SAOL program can be told its K-rate at runtime?

There's also the matter of naming the ports ... LADSPA ports generally
have reasonably intelligible names; how could sfront be told what the
names are and which port they go with?

Any other obstacles?

I'd be writing plugins today if I could do them in a higher-level
language like SAOL... hell, we could mine the Csound CD for cool
processing instruments and churn out plugins by the dozen!

-- 
................    paul winkler   ................
 custom calendars:   http://www.calendargalaxy.com
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        home page:  http://www.slinkp.com


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