[linux-audio-dev] XAP spec & PTAF comments [merge]

[Steve Harris]

On Sat, Feb 08, 2003 at 03:06:40 +0100, David Olofson wrote:
> On Saturday 08 February 2003 02.17, Tim Hockin wrote:
> [...]
> > Assuming we really want to allow soft-limits (which I just don't
> > get), we can just say that if you want a hardlimit, constrain it
> > internally.
> 
> Yeah.
> 
> As to soft limits, I think the main point is to relieve the plugin 
> author of the task of figuring out the absolute minimum and maximum 
> control values that could possibly generate any interesting results, 
> so he/she doesn't have to release a modified plugin under a different 
> major version number later on, just to extent some control ranges.
> 
> If you can't decide on the "useful" range, just throw something 
> reasonable into the range hints, and clamp to some bigger range that 
> you know is technically safe for the algorithm. If users want to look 
> for cool effects outside the "official" ranges, they can, and 
> although plugins might produce evil noises (which some actually might 
> find useful), they won't crash or anything like that.

This is exactly what I do in LADSPA and it works quite well. Many plugins
make interesting noises if you give way out of range controls.
 
> > I'm all for optimizations, but really, this is a MICRO MICRO MICRO
> > MICRO optimization.  SOMEONE SOMEWHERE is going to do a conditional
> > and constrain. Be it the host or the plugin.
> 
> Yes. The only exceptions would be when you have a hard limited output 
> that's within the range of a hard limited input, and when you have 
> prerecorded data. However, the latter case only applies if you assume 
> that recorded data will be destructively processed whenever you 
> connect something. *heh*

Many controls dont need to be clamped at all, it might do something odd if
you go outside the ranges, but it wont crash.

- Steve