[ardour-dev] 0.99.1 causing plugin crash?

fons adriaensen fons.adriaensen at skynet.be
Fri Feb 10 16:11:46 PST 2006

On Fri, Feb 10, 2006 at 06:56:21PM -0500, Paul Davis wrote:
> On Sat, 2006-02-11 at 00:52 +0100, fons adriaensen wrote:
> > 
> > I'm having a similar problem with a postfader mono plugin in a
> > stereo track. I've been tracing the plugin and found out the
> > following: when the track is muted, the plugin is still called,
> > but only one input is muted. 
> can you expand on precisely what you mean by that?

I mean that when the track is muted, one of the inputs is not
cleared to zero, and the output from cycle N is fed back as the
input in cycle N+1.

Even if the the plugin does support PROCESS_INPLACE (and this
one does), this will radiply go to Inf if there is any gain
in the plugin.

> > To make things worse, the input and
> > output buffers are the same, so if there is any gain in the plugin
> > things will explode rapidly.
> ardour doesn't support LADSPA plugins that do not support
> PROCESS_INPLACE, or VST plugins that do not have processReplacing()
> methods. hence, yes, input buffer is always the same as the output
> buffer. if a plugin can't handle that, it should not be marked as being
> capable of doing inplace processing.

No plugin can be expected to handle the situation of being placed
in a feedback loop as described above.


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