On Monday 16 June 2003 18.03, Jaroslav Kysela wrote:
[...]
> > Maybe ALSA shouldn't mess with (N)RPNs at all, unless
> > applications ask for it?
>
> I think that events are clear, so all applications using direct
> sequencer API should handle them as well.

Yes, that's a point... However, if ALSA intercepts the underlying CCs 
for (N)RPNs, there is no way to use them as normal CCs by just 
looking at the (NON)REGPARAM events. For examyple, if something sends 
only CC 98 ("NRPN fine"), the app will get nothing.


[...14 bit controls...]
> Yes, Paul mentioned it and I see that the standard is not so good.
> Does it affect also XRPN encoding (some LSB or MSB bytes might be
> missing)?

Well, the "Data Entry" CC pair *is* one of those ugly 14 bit things.


> In that case the current implementation is broken.

That goes for Audiality too. Dunno if I care, because I can't really 
do anything useful with 7 bit values anyway. I just store the other 
CC values and act on CC 38 ("Data Entry (fine)").

I think people would expect ALSA to do the Right Thing, though - 
whatever that is....


> I see some ways to do things correctly:
>
> 1) duplicate events (deliver both raw CONTROLLER + combo events)
> 2) do not generate combo events at all, use only raw controller
> events
> 3) introduce timeouts (I hate this idea)

Unless I'm mistaken about the (N)RPNs being normal 14 bit controllers, 
1) would require timeouts as well - although it would allow 
applications to bypass them by grabbing the raw CCs instead.

Either way, if that timeout isn't part of the spec, there is no way of 
implementing this correcly. You can't wait forever, and it's not safe 
to set it short and let occasional wrong values through. :-/


> I will stay with 2) for the moment (so nothing will change).

Ok.


BTW, what about apps sending (NON)REGPARAM events? Is it possible, and 
if so, are they converted into CCs even when passed directly to other 
ALSA sequencer apps?


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

.- The Return of Audiality! --------------------------------.
| Free/Open Source Audio Engine for use in Games or Studio. |
| RT and off-line synth. Scripting. Sample accurate timing. |
`-----------------------------------> http://audiality.org -'
   --- http://olofson.net --- http://www.reologica.se ---



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