Subject: Re: [linux-audio-dev] XAP and Event Outputs
From: David Olofson (david_AT_olofson.net)
Date: Wed Dec 11 2002 - 18:37:30 EET
On Wednesday 11 December 2002 15.25, Tim Goetze wrote:
> David Olofson wrote:
> >So, sort them and keep track of where you are. You'll have to sort
> >the events anyway, or the event system will break down when you
> > send events out-of-order. The latter is what the event processing
> > loop of every plugin will do, BTW - pretty trivial stuff.
>
> what you describe here has a name: it's called queuing.
Of course. But it doesn't belong in the event system, except possibly
as a host or SDK service that some plugins *may* use if they like.
Most plugins will never need this, so I think it's a bad idea to
force that overhead into the basic event system.
It's sort of like saying that every audio stream should have built-in
EQ, delay and phase inversion, just because mixer plugins will need
to implement that.
> >Do event processors posses time travelling capabilites?
>
> delays based on musical time do, whatever you like to call
> it.
Then they cannot work within the real time net. They have to be an
integral part of the sequencer, or act as special plugins for the
sequencer and/or the editor.
> >It sounds like you're talking about "music edit operation plugins"
> >rather than real time plugins.
>
> you want to support 'instruments', don't you? 'instruments'
> are used to produce 'music' (usually), and 'music' has a
> well-defined concept of 'time'.
Yes - and if we want to deal with *real* time, we have to accept that
we cannot know about the future.
One may argue that you *do* know about the future when playing
something from a sequencer, but I strongly believe that is way beyond
the scope of an instrument API primarilly meant for real time work.
> >If you just *use* a system, you won't have a clue what kind of
> >timestamps it uses.
>
> yeah, like for driving a car you don't need to know how
> gas and brakes work.
Well, you don't need to know how they *work* - only what they *do*.
> >Do you know how VST timestamps events?
>
> nope, i don't touch proprietary music software.
I see.
Either way, it's using sample frame counts.
//David Olofson - Programmer, Composer, Open Source Advocate
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