[linux-audio-dev] Plugin APIs (again)

Tim Hockin thockin at hockin.org
Sun Dec 8 17:25:59 UTC 2002


> I'm afraid I'm not familar with the AudioUnits API, but I dont/think/ this
> situation requires the instrument to inform the host, it should just be
> able to damp (slew rate limit) the control, shouldn't it? The result from
> playing back automation data will be the same, so no harm done.

Well, if the host is auto-generating a UI, or it is, in-fact tracking the
values itself (no get() method) then it needs to know.

> > Also to think about - what if the host sends a bad value, and a control
> > wants to reject it?  Ahh, asyncronicity.  I guess for this case the plugin
> > sends back some FAIL event or simpler sends back a CTRL_CHANGE with the old
> > value (or the min/max if the host has gone too far).
> 
> Bad value? LADSPA has the concept that there are no bad values, the plugin
> has to accept anything. It can choose to ignore it, but it mustn't
> segfault or whatever.

I was more thinking that some controls would disable certain functions, or
limit other controls.  Assuming that there is no get() method for a control,
and the host knows the value by remembering, then the plugin does need to
alert the host if it 'ignores' something, or the host will have the wrong
value.

> England, UK. GMT+1. I'm not a mornings person though ;)

Ahh.  Sunny England.  For the record, I am in the San Francisco area.

Tim



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