[linux-audio-dev] XAP and these <MEEP> timestamps...

[Tim Hockin]

> Yes - as long as the song position doesn't skip, because that won't 
> (*) result in tempo events. Plugins that *lock* (rather than just 
> sync) must also be informed of any discontinuities in the timeline, 
> such as skips or loops.

OK, it took me a bit to grok this.  We have four temporal concerns:

1) plugins that need to do things in step with the tempo
   - they have a TEMPO control
2) plugins that need to do things on tempo milestones
   - they have a TEMPO and can host callback for music-time
3) plugins that need to do things at some point in absolute time
   - they have the sample rate, no worries
4) plugins that need to do things at some point in song time
   - they have a TRANSPORT control

> (*) You *really* don't want two events with the same timestamp,
>     where the first says "tempo=-Inf" and the other says
>     "tempo=120 BPM". But that would be the closest to the correct

ick...

> 	Tempo changes
> 		Whenever the tempo changes, you get a sample
> 		accurate event with the new tempo.
> 
> 		Unit: Ticks/sample

Before I go any further: What's a tick?

> 	Meter changes
> 		When PPQN (who would change *that* in the middle

Define PPQN in our terms?  Pulses of...

Then I can digest the rest of this email :)