Re: Suggestions for volume controls?
Re: Suggestions for volume controls?
- Subject: Re: Suggestions for volume controls?
- From: William Stewart <email@hidden>
- Date: Mon, 13 Feb 2006 11:17:24 -0800
Have a look at the AudioUnitParameterInfo struct - and in the SDK,
the sample effect unit, where a parameter is defined that will draw
menus - we call this an indexed parameter, and you can give each
value of the index a name.
You express the parameter's natural range and units - so say -120dB
to 6 dB. You will then have parameter values set within this range.
You can specify a display curve that can be used by a generic view
for instance, when displaying your parameter. We provide linear
transformations, so that a slider for instance, can translate to/from
a parameter's value (using these optional display curves)....
All you have to do here is:
describe the parameter in its most natural form
deal with the incoming values
HTH
BIll
On 12/02/2006, at 8:03 AM, Jeff DuMonthier wrote:
I'm trying to convert a VST plugin to an audio unit and I'm
wondering how to do a volume control, among others. Eventually I
may use a Cocoa view, but it's just the default interface for now.
In VST the control just returned a value from 0.0 to 1.0 and I have
some custom code for linear, log or log-linear parameter
normalization I reuse all the time that made it easy to do a log-
linear control from -INF to +6dB. I haven't seen any documentation
on how to do various types of controls, but it looks like you just
define a linear range of values and select a unit. I'm assuming if
I set the range from -100 to +6 and use
kAudioUnitParameterUnit_Decibels, the value it will return will be
between -100.0 and +6.0. It doesn't display in dB and convert to a
gain does it? How would I do a volume control that went from -INF
to +6dB without overloading all the built in code, or is that the
only option? What have others done for this? I'd rather not have
to overload code that handles parameter automation because I really
don't want to have to reimplement that.
Is there some documentation or some good examples somewhere on how
to do different controls like this? I may also have to do some
which are ranges with only discrete values in the range allowed. I
suppose I could just pretend it's linear even though it isn't.
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