[gmpi] Re: Reqs 3.8 Events - ramped events
- From: David Olofson <david@xxxxxxxxxxx>
- To: gmpi@xxxxxxxxxxxxx
- Date: Tue, 13 Jan 2004 13:39:51 +0100
On Tuesday 13 January 2004 02.48, Tim Hockin wrote:
> On Mon, Jan 12, 2004 at 09:53:26AM -0700, Mike Berry wrote:
> > GMPI hosts shall provide translation facilities for connections
> > between plugin controls which share a primary type but differ on
> > secondary characteristics (such as ramping support).
>
> I'm no longer conveinced we even need this requirment at all. If
> we mandate that hosts allow ramped outputs to send to a non-ramped
> input, we force every host to insert ramp->point converters.
> Better, I think (I know I flip-flopped on this a bit), is to assume
> all real-number inputs are capable of some semblance of ramps. If
> your input LEGITIMATELY is not capable of ramps, you may want to
> consider a non-float type, or just handling ramps as points. If
> you *should* be ramping but aren't, your plugin will just sound
> worse than it could.
>
> What think?
Yeah, that's fine with me.
> As for the case of very long ramps, I've had a read of the AU docs.
[...]
> It may not be perfect, but it's interesting.
Yes... It's interesting, but I don't quite like it, for various
reasons. Most importantry, there are no less than 5 possible cases;
1) no ramp,
2) full buffer ramp,
3) starts within buffer,
4) ends within buffer, and
5) starts and ends within buffer.
And what about multiple ramps per buffer?
Unless I'm missing something, XAP/Audiality style ramp events are *so*
much easier to deal with. It it's simplest form; linear audio rate
ramping, assuming <target, duration> events are used;
In the event decoding switch:
case EV_RAMP:
if(ev->duration)
delta = (value - ev->target) /
ev->duration;
else
{
value = ev->target;
delta = 0;
}
break;
In the DSP loop:
<use value for something>
...
value += delta;
Besides, the AU way doesn't even provide any additional information or
capabilities, AFAICT; it might even have some more restrictions.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
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