25 Sep
2011
25 Sep
'11
3:53 p.m.
On 09/25/2011 05:10 AM, Fons Adriaensen wrote:
On Sun, Sep 25, 2011 at 09:52:23AM +0100, Aurélien
Leblond wrote:
[snip]
I'm porting the AMS internal modules to LV2
plugins to be used in Ingen.
Small problem is, AMS uses VC (even the output of the VCOs that
produce sound) when Ingen uses PCM...
?? You seem to be confusing some things.
2. Control in/out ports. These are technically identical to
audio ports (full sample rate), but the signals carried
on them are normally not meant to be audio. How they are
[snip]
3. Input ports corresponding to GUI widgets. These are control rate,
read once per block. They can be int or float. For continuous values
[snip]
And I think part of the confusion is that LV2 calls #3 a "control port",
and doesn't currently have anything like #2.
On 09/25/2011 03:52 AM, Aurélien Leblond wrote:
So far, my research seems to lead that a simple
multiplication by 16
of the VC output should convert it to PCM, and vice-versa.
That doesn't seem right though, as I would think the sample rate
should be involved in this conversion!
If your the same dude I met on IRC doing this exact same thing... you
misunderstood what was said about 16. I was saying that[1] I've heard
that sometimes people implement CV ports at 1/16th the audio sample
rate. However it's simpler to just stick with the audio sample rate.
Also, in old-style analog synths the CV signal correspends to 1
Volt/octave and has a range (0.0, +inf).[2] In contrast, floating point
audio has a range of [-1.0, 1.0]. There is no relationship between a
control voltage signal (e.g. the position of a fader) and a PCM audio
signal.
-gabriel
[1] ...based on my understanding of some discussions here
[2] http://en.wikipedia.org/wiki/CV/Gate