Help with these subjects for OHM...

Harbinger · October 22, 2009, 17:57:35

Must research these topics. Please provide links (or describe them meticulously) so i can fully understand these subjects.

Mix Modes (Wet Subtract, etc) in the Plugin section of the General tab.
Resampling, WFIR, & FFT (Player options) Full description
Soft Panning (Old feature) What is it?
Envelope Carry: Still don't know what it does.
Soundfonts: How can they be used? Is it worth including in the manual?

Saga Musix · October 22, 2009, 18:49:25

QuoteSoft Panning (Old feature) What is it?

New feature actually, if you consider that this is always enabled when using mixmode RC3. This will treat (correct me if I'm wrong, Relabs) panning as balance, which makes a huge difference when panning stereo samples and produces a "softer" panning for mono samples.

QuoteEnvelope Carry: Still don't know what it does.

When triggering a new note of the same instrument, the envelope is carried, i.e. not retriggered.

QuoteSoundfonts: How can they be used? Is it worth including in the manual?

Well, given that OpenMPT's soundfont support is rather poor, I personally don't make much use of this feature, but since especially beginners often lack samples, their only supply is the GM.DLS soundfont which is included with every modern version of Windows. I don't think it's much more than an instrument collection.

Paul Legovitch · October 22, 2009, 19:17:58

I find that Envelope Carry is really helpful for the pan (or flter) envelope of chords or vibes-like instruments for example. It helps a lot to hide the fact that you are playing the same sample over and over, it feels less mechanical and repetitive.

While we're at it, I've always wondered what does the sweep value in the sample tab (next to the depth and rate of the vibrato). It doesn't seem to do much when I change it.

Saga Musix · October 22, 2009, 19:28:18

It pretty much does "nothing" because it's done completely wrong (at least for IT format) until (and including) version 1.17.03.02. Sweep is the "fade-in speed" of the vibrato, so the higher the value, the faster the vibrato will reach its highest amplitude. In XM format, a sweep value of 0 will fade it in immediately, but in IT format, no vibrato should happen at all. This is the part where MPT fucks up greatly, because the implementation is identical for both formats. Moreover, the algorithm how the sweep is applied is wrong for IT format.

Paul Legovitch · October 22, 2009, 19:43:26

That's great info, thanks !

Quotethe algorithm how the sweep is applied is wrong for IT format.

Theorically how is it supposed to work ? The value is based on a number of tick before full vibrato depth or something else ?

Also, I take it can't be heard while playing the sample in the sample tab but only when playing a track, is it ?

Saga Musix · October 22, 2009, 19:47:33

QuoteTheorically how is it supposed to work ? The value is based on a number of tick before full vibrato depth or something else ?

I don't know since ITTECH.TXT is a bit unprecise here. Or rather, the example code is written in ASM and the non-ASM explanation is unprecise.

Quote
Also, I take it can't be heard while playing the sample in the sample tab but only when playing a track, is it ?

It can always be heard. Note that in IT format, all three vibrato variables have to be greater than 0 to take effect, though.

residentgrey · October 25, 2009, 02:04:27

Is this for the wiki? I r confused...

Rakib · October 25, 2009, 08:22:23

No the manual:
http://forum.openmpt.org/index.php?topic=3405.0

Saga Musix · October 25, 2009, 10:48:45

I honestly wonder if the current wiki shouldn't be ditched at some point anyway. Seems like a lot of spam bots register there, and some information is outdated anyway. And I cannot really say that i'm a fan of the XWiki software...

residentgrey · October 25, 2009, 18:13:05

COOL BEANS! Well needed!

Harbinger · October 28, 2009, 18:29:24

Thanks Jojo for the info.

Now can any of you audio technicians explain the WFIR and FFT aspects of resampling? or Mix Modes?

g · October 28, 2009, 19:37:05

Quote from: "Harbinger"Now can any of you audio technicians explain the WFIR and FFT aspects of resampling?

I hope I'm not offending anyone now, but I think none of the current members/developers are into signal processing (me included). However, here's a wikipedia article on Window functions if you'd like to know more.

Saga Musix · October 28, 2009, 21:19:18

I cannot really see how a Fast Fourier Transformation is being used in the resampling options, though.

Sam_Zen · October 29, 2009, 03:10:19

me neither

bvanoudtshoorn · October 29, 2009, 06:30:45

I'm more than happy to explain FFTs and so on, Harbinger (they were pretty much the crux of my thesis), but, as Jojo says, I doubt they're actually being used in the system...