Subject: Re: [linux-audio-dev] Plugin APIs (again)
From: David Olofson (david_AT_olofson.net)
Date: Wed Dec 04 2002 - 23:49:11 EET
On Wednesday 04 December 2002 22.29, Steve Harris wrote:
> On Wed, Dec 04, 2002 at 10:05:25 +0100, David Olofson wrote:
> > Nice but simple:
> > Accept disconnected ports, and just check the
> > pointers, or whatever. (Note that passing NULL
> > buffers might have other users. In Audiality,
> > it's legal for inputs, and means "silence for
> > one frame". IIRC, you can turn the feature off,
> > if you like, forcing the host to always pass
> > valid buffers.)
>
> This one sounds good to me, Mattias suggested something similar for
> LADSPA.
Especially for the inputs, where it coincides with the really rather
useful "NULL input instead of a buffer means silence" feature - which
actually is the same thing as "this input is not connected right
new", for all practical purposes. (Unless you want to emulate pops
and clicks generated when pulling and plugging analog cables, that
is. ;-)
However, it's not fun when you're in an inner loop like this:
for(i = 0; i < frames; ++i)
{
float s = inputs[0][i];
...interesting code here...
outputs[0][i] = s * controls[0];
outputs[1][i] = s * controls[1];
outputs[2][i] = s * controls[2];
outputs[3][i] = s * controls[3];
outputs[4][i] = s * controls[4];
}
Sure, you could turn the loop inside out, but if the "interesting
code" is complicated, you'll want an intermediate buffer, not to have
5 copies of that code.
Why not keep it simple, and have the ability to say that the host
shouldn't pass NULL pointers for output buffers to this plugin?
//David Olofson - Programmer, Composer, Open Source Advocate
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