pre-gen

[supersonic]

I was wondering if there is definite knowledge as to when the pre-gen works most? For example. Does it work when the VI is in the V-rack or has AUX tracks playing some of the additional VI outputs for further effects?

[Michael Canavan]

As far as I know PreGen works on MIDI and audio tracks in Sequence Chunks. So whether a virtual instrument is in a V-Rack or not the MIDI and effected audio data is pre rendered in your Sequence Chunk. Now I'm not sure about Aux tracks, it's typical of any DAW not to be able to freeze Aux tracks, for instance tracks from multi audio out instruments etc. Any track with the record enabled will not be pre rendered as well.

Someone else might have more information on Aux tracks, but any MIDI track feeding a non multi out instrument or audio track with effects etc. is pre rendered.

[KenNickels]

As far as I know PreGen works on MIDI and audio tracks in Sequence Chunks. So whether a virtual instrument is in a V-Rack or not the MIDI and effected audio data is pre rendered in your Sequence Chunk. Now I'm not sure about Aux tracks, it's typical of any DAW not to be able to freeze Aux tracks, for instance tracks from multi audio out instruments etc. Any track with the record enabled will not be pre rendered as well.

Someone else might have more information on Aux tracks, but any MIDI track feeding a non multi out instrument or audio track with effects etc. is pre rendered.

That's interesting. All of my VI's are multi's with direct outs to audio tracks. They are always real time when the VI edit window is open. And they MUST be open, otherwise they are pre-gen and will not work. I've been dealing with this issue for a long time. Where is this specified, 'multi-outs' problem?

[Michael Canavan]

All of my VI's are multi's with direct outs to audio tracks. They are always real time when the VI edit window is open. And they MUST be open, otherwise they are pre-gen and will not work. I've been dealing with this issue for a long time. Where is this specified, 'multi-outs' problem?

This is such a bizarre problem to me? So in your set up if you don't have the GUI of a multi out instrument open it does what?

otherwise they are pre-gen and will not work.

What happens? what doesn't work? Curious because everyone seems vague to me about this issue, and since it doesn't show up on my system I can't replicate the problem. Plug ins that are multi out simply use more CPU, but since they're multi out in the first place it's not like say Kontakt with 8 instruments loaded into an instance uses any more CPU than 8 instances of Kontakt with a single instrument and audio out that gets PreGen benefits.
At least that's how it works here.

[KenNickels]

As I understand it, when the VI window is closed it goes into pre-gen by default. When it's open you have the choice of pre-gen or real time through the mini menu. But whatever the case, if it's pre-gen a whole slew of problems result, which I have exhaustively described to MOTU. The system becomes completely unusable. So, OK, I keep them open all the time now. But I am at the limit of my screen real estate too. And if I used one instance per instrument I would have maybe 7-8 instance/instruments on the screen when my template needs 48 tracks/instruments. It doesn't matter if it's Play or Kontakt, same thing.

[supersonic]

So if I get it right, an 8 MIDI channel Kontakt Instance that has each of the 8 instruments feed a separate multi-out uses quite a bit more CPU then 8 instances of Kontakt having just one instrument and closed to use Pre-Gen?

[KenNickels]

So if I get it right, an 8 MIDI channel Kontakt Instance that has each of the 8 instruments feed a separate multi-out uses quite a bit more CPU then 8 instances of Kontakt having just one instrument and closed to use Pre-Gen?

Well, that's the odd thing about it. No, according to the Mac utilities like Activity Monitor or Menu Meter, the CPU metric is the same whether 1/1 or 8/1 output/instance. That's not to say that the CPU isn't 'used' more, only that it isn't 'measured' more. I don't understand it. I only know that I must keep the VI edit windows open to use DP.

[supersonic]

How so? The instruments don't play otherwise? I have sessions with multiple instances playing, all closed.

[KenNickels]

Really? I want to rip my hair out in that case. While editing, clicked notes last only a millisecond or so. Cannot scrub with the wiper because of this. Then system becomes unusable and cannot save project or close DP. It is 100% predictable.

[Michael Canavan]

Really? I want to rip my hair out in that case. While editing, clicked notes last only a millisecond or so. Cannot scrub with the wiper because of this. Then system becomes unusable and cannot save project or close DP. It is 100% predictable.

Like Supersonic I do not experience any of that. Opening multiple plug in instances for multi instrument plug ins like Kontakt just uses slightly more CPU on my system than when the instances are closed.

This has always led me to believe strongly that PreGen issues for people are due to a misbehaving plug in or hardware driver. The more complex plug in protection schemes like Waveshell, or system changing things like hardware plug in accelerators like UAD cards, or VEP instances using gigibit ethernet etc. Or even a really badly written plug in that does something to the whole systems stability. It can happen.

I use VEP sometimes, and have Waveshell for about 4 Waves plug ins. No hardware plug in card, RME, Logitech, NI, Slate, and Ableton drivers for various things.

The bad behavior I get is a crash on start which seems to be due to either a Metric Halo transient or Slate Trigger plug in.. It always loads fine the second time.. odd but not that big of a deal.