[linux-audio-dev] more on XAP Virtual Voice ID system

[Tim Hockin]

> The main difficulty I see with the VVID system is how to initialize 
> parameters on a new voice before the voice is activated with a VoiceOn 
> event.

After, or rather - at the same time.  The host just has to make sure the
VoiceOn arrives first.  This is what is currently in the header in my
working dir.

Send a new VVID to the VOICE control with timestamp X for note-on
Send any initial voice-params with timestamp X
Send 0-VVID to the VOICE contol with timestamp Y for note-off

Alternatively, rather than a VOICE control, just have special
VOICE_ON/VOICE_OFF events.

> -first- order on timestamps
> -second- put voice-on ahead of all other event types.
> A little ungainly, but effective as it frees the plugins to assume that 
> they'll get voice-on first but must consider all other events on that 
> timestamp as arguments to the initialization of the voice. Of course this 

not all events with that timestamp - only per-voice controls with the VVID
that was just turned on.  All per-voice events have a VVID.  So it is easy
to know if that VVID is active - if not, the host screwed up.

What I am still fighting with is the idea that the host pre-allocates VVID
space.  How much space for each VVID?  Any imposed structure?

Tim