Re: [linux-audio-dev] LADSPA clarifications?

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Subject: Re: [linux-audio-dev] LADSPA clarifications?
From: Mike Rawes (mike_rawes_AT_yahoo.co.uk)
Date: Mon Jul 15 2002 - 14:12:18 EEST

On Mon, 15 Jul 2002 12:00:37 +0200
Jürgen Zimmermann <jnzimmer_AT_informatik.uni-kl.de> wrote:

> Hello,

Hi

> I just joined the "linux-audio-dev" list a few days ago,
> and after some time studying the ladspa.h file, I have
> still some questions left:
>
> 1. Must the buffers assigned to audio input and audio output ports
> have the same length? Where is this stated???
> The sample implementations suggest so, though...

Yes, they must. It isn't stated anywhere explicity AFAIK, but the run()
function is only passed one value for the sample count, so this would
have to indicate the size of all buffers. The buffer size need not be
constant for every call to run(), though.

> 2. Is there any range constraint applied to the audio content
> communicated by the audio input/audio output ports?
> VST e.g. does restrict the range from -1.0 to +1.0.

I'd say that if the audio ports are carrying audio data (as in,
something that would eventually come out of speakers), this range would
be the suggested constraint (I think there has been discussion about
this before, but before I got here...)

However, it is possible that you may use ports of type LADSPA_PORT_AUDIO
to carry other types of data - I've made plugins that use
LADSPA_PORT_AUDIO ports for e.g. frequency inputs, as CONTROL type ports
don't always have the resolution needed (try doing a cutoff sweep on a
filter using a control port, and you'll hear what I mean!).

>
> So long,
> Jürgen
>
> --
> ----------------------------------------------------------------
> Jürgen Zimmermann Department of Computer Science
> jnzimmer_AT_informatik.uni-kl.de University of Kaiserslautern
> Phone: +49 631 205 3280 P.O. Box 3049
> Fax: +49 631 205 3299 67653 Kaiserslautern, Germany
> WWW: http://wwwdbis.informatik.uni-kl.de/staff/Zimmermann/
> ---------------------------------------------------------------- 

-- 
Myk

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