Subject: Re: [linux-audio-dev] Re: Feedback in LADSPA
From: David Olofson (david_AT_gardena.net)
Date: la maalis 11 2000 - 14:36:48 EST
On Fri, 10 Mar 2000, Alexander Ehlert wrote:
> On Fri, 10 Mar 2000, David Olofson wrote:
>
> > On Thu, 09 Mar 2000, Jarno Seppanen wrote:
> > > > Feedback loops in the host's network are beyond the scope of this API. The
> > >
> > > Stressing out: this does not need changes in the current API!
> >
> > Not completely true, if the feedback delay time is to be accurate.
> > Plugins have to specify a processing delay value. Sounds pretty
> > simple, but there is one problem; the delay may depend on control
> > inputs...
>
> Another problem is that the minimum feedback delay is bound to the process
> buffer size. No data processed -> no feedback :)
Yes; I thought that way pretty obvious. :-) Of course, plugins have
to tell the host about any buffer size restrictions, but as of now,
it's up to the host to use suitable buffer sizes. (Unless I've missed
some note in the current API spec.)
Aah, analogue is so much
> easier... And changing feedback delay times in realtime is surely
> complicated, just imagine some really sick configurations were some
> feedbacks could be depended from others...
>
> Definitly a NO for feedback in LADSPA.
Ok, you do need one callback function (or something) to give LADSPA
better feedback support than most existing plugin APIs, but that
might be one piece to many to say LADSPA is simple...
> Probably even for MUCOS?
I don't see why. All the complexity is on the host side, and a plugin
developer who thinks it's too complicated to express processing
latency as a function of some input parameters could just use some
approximation and say "...FEEDBACK_LATENCY_BROKEN" or even ignore it
and say that feedback isn't supported.
> Anyway I think, stuff like that should be done within one plugin.
That's fine if every user is a programmer, and no one wants to use
the API for prototyping. This is not the case, though...
//David
.- M u C o S --------------------------------. .- David Olofson ------.
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