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

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Subject: Re: [linux-audio-dev] LADSPA clarifications?
From: Jürgen Zimmermann (jnzimmer_AT_informatik.uni-kl.de)
Date: Mon Jul 15 2002 - 14:10:08 EEST


> a) if you're an app (a ladspa host)
>
> they must all be at least long enough to handle the SampleCount argument
> you pass to the plugin's run() method.

Agreed. So: Please, can someone state this explicitly in the LADSPA
specification for
clarity purpose???

> noone will spank you if your buffers are too big, but your app might go
> "kaboom" if you pass a longer SampleCount than what you've allocated.

Yes, totally what I thought of...

> you choose the SampleCount to run() for, and you choose the lengths of
> the buffers ... in practice, if an app is coded to always call run with a
> SampleCount of 256 (say), then there's not much point allocating either
> input or output buffers any longer than that, which is why the code you've
> looked at allocates buffers all of the same length.

Never mind. I just want the specification to include the above statement
that input and output buffers must have a reasonable amount of space
allocated
by the host.

> b) if you're a plugin
>
> well, the lengths of the buffers isn't up to you, but you should hope the
> app author didn't screw up, and in your run() method you have to assume all
> the input and output buffers are at least as long as the SampleCount the
> app asked to run for.

Yes. You have to rely on the host to provide enough space. That's all I
wanted
to know.

> > 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.

> by convention, -1.0 to 1.0 (in most plugins and hosts)

Why only "by convention". Put it into the specification, then it's
"by specification". Wouldn't a common range for all plugins be the
better idea?

So long,
  Jürgen


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