[linux-audio-dev] LADSPA2: logarithmic hint

Steve Harris S.W.Harris at ecs.soton.ac.uk
Tue May 2 16:21:44 UTC 2006


On Tue, May 02, 2006 at 12:15:20PM -0400, Paul Davis wrote:
> On Tue, 2006-05-02 at 17:57 +0200, Alfons Adriaensen wrote:
> > I can't imagine any sane interface standard for audio controls without a
> > way to say that the natural way to represent a port's range is exponential.
> 
> saying that the port range is exponential doesn't pin it down very much.
> it still requires the host to make decisions about precisely what kind
> of exponential curve to use for the range, and it may get it wrong. 

The "type" is irrelevant, the problem is that what I generally want to say
is "this goes from 0Hz to fs/2Hz, and I want it to be logarithmic", but
you can't say that literally, so you have to say "this goes from
fs/10000Hz to fs/2Hz", which tends to make the bottom value a bit random.

I don't know what the correct solution is, possibly just providing a rule
for the host to caluculate what it should use instead of log(0) is enough,
but I'm not sure what the rule should be.
 
> > The reason why it gets them wrong is probably
> > because the code handling defaults is something like 10 times more
> > complicated than it need be.
> 
> care to suggest a simpler approach?

LADSPA defaults are broken, and hopefully not relevant.

- Steve



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