[linux-audio-dev] XAP: SILENT event handling

[David Olofson]

On Monday 09 December 2002 18.49, Steve Harris wrote:
> On Mon, Dec 09, 2002 at 05:08:29PM +0100, David Olofson wrote:
> > > OK, that sounds useful, but also really hard. Realisticly a
> > > reverb can't tell when its gone to zero except by inspection
> > > and guesswork.
> >
> > Well, just don't do it if it's too hard. Keep in mind though,
> > that by doing that, you're only moving the problem over to the
> > host and/or the user.
>
> Good! If the host really wants to know it was waste cycles doing
> it. Most of the time the host wont want to know, so it will just
> waste the plugin cycles trying to calculate when its silent
> (especially if it has to inspect internal buffers). I guess you
> could indicate to the plugin wether you care, but thats getting
> more complex.

Yeah... *hehe* Good point.


> > Well, there's always the output meter hack. :-)
>
> Yep, and that requires no support from the plugin.

Exactly.


> > I guess there is a reason why most plugin APIs have this feature
> > - but there must also be a reason why so many plugins don't
> > implement it. :-)
>
> One thing we should have is a latency indication. Its blantantly
> missing from ladspa.

Yes indeed. Missing in most other APIs as well. (VST as well, IIRC.)


> Though its probably only useful on inline processing plugins, not
> instruments.

On the contrary, I think it's *very* important for instruments as 
well; especially with percussive sounds. If you want to use two 
synths together, and one or both for some reason have non-zero event 
timestamp -> audio output latency, you'd really want the host to be 
able to compensate for it, so you can start tweaking with the outputs 
in exact sync.

I've mixed percussion sounds from SoundFonts on PCI cards with MIDI 
syths. Need I say more? :-)


//David Olofson - Programmer, Composer, Open Source Advocate

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