Plug-ins mode pre-gen

[oshtakuta]

Hi!In real- time all well and good!,but what is the mode plug-ins pre-gen?

[Shooshie]

In an effort to improve efficiency of plugins and VIs, especially in large templates on computers with limited CPU/RAM capacity, MOTU added "pre-gen" to look ahead in each audio or VI track during periods when the CPU is not straining, creating a temporary track in RAM (maybe on Disk; I don't know about that for sure) with plugin effects rendered and VIs pre-recorded.

You may opt-in or opt-out using the mini-menu in each plugin/VI. There are conditions that prevent pre-gen from happening: if the plugin (or VI interface) window is open, it will not pre-gen, since you probably have it open for a reason, which may involve changes that would negate the temporary track's usefulness. When you close the window, DP takes a moment to render that track, so you may see the CPU meters shoot up momentarily. But a fully-pre-gen rendered template runs very smoothly with little CPU effort.

Shooshie

[mhschmieder]

I think this wins an award as most useful and informative post of the year so far. This excellent write-up helped me take this in in a way more comprehensive and deep level than I had previously -- and I thought I already understood it before.

[oshtakuta]

Shooshie,thank you,it's important to me and sorry for my English

[Tritonemusic]

There are conditions that prevent pre-gen from happening: if the plugin (or VI interface) window is open, it will not pre-gen...

I just wanted to add that pre-gen won't be active on a track if it's record-enabled, either.

[daniel.sneed]

Would someone (Shooshie?) confirm that pregen is not active for plugins sitting in a V-Rack?
I am thinking about the heavy plugs sitting in a Masterfader.

[Shooshie]

There are conditions that prevent pre-gen from happening: if the plugin (or VI interface) window is open, it will not pre-gen...

I just wanted to add that pre-gen won't be active on a track if it's record-enabled, either.

Sort of. The actual rule concerns Virtual Instruments. If any MIDI track assigned to a VI is record-enabled, that VI track will not pre-render. Stands to reason that you wouldn't want to pre-render a track you're about to record over.

As far as pre-render on an audio track that is record-enabled, we may need more info. It's not in the manual, and two MOTU tech support people (Robin and Chad) seem to think that it doesn't matter. But I can't say for sure one way or the other, right now. There was a time when record-enabled tracks would not play back. You had to disable the record button just to hear the audio. If pre-render existed before that changed, then of course, it would not pre-render. But since that changed (I think that was DP6, but don't quote me) it appears that pre-rendering works on record-enabled tracks, I mean... as long as you are not recording. ( )

Also, if you look it up in the DP Manual you won't find pre-gen in the index, nor even Pre-Render, which is the word they use. To look this up, you'll have to search the Index for: "Run this instance in real-time" which is on page 836 of the DP8 manual.

Would someone (Shooshie?) confirm that pregen is not active for plugins sitting in a V-Rack?
I am thinking about the heavy plugs sitting in a Masterfader.

Pre-rendering is not active for Aux tracks. Since you cannot put a MIDI or Audio track in a V-Rack, pre-rendering is not active for plugins on Aux tracks or Instrument tracks in a V-Rack. But as far as I can tell, pre-rendering IS active for INSTRUMENTS in the V-Rack. I have confirmed that with MOTU Tech Support. (Had to call in the big guns for that one.)

The above paragraph is awkward. Let me clarify: Unless Magic Dave says otherwise, NO PLUGINS in V-Racks will be pre-rendered. Instruments in V-Racks WILL be pre-rendered. Consider everything in a V-Rack except the top insert in Instrument Tracks (the location of the instrument itself) to be an Aux track, and Aux tracks do not pre-render.

To be certain, I called MOTU Tech Support.

Virtual instruments that are receiving MIDI output from MIDI tracks that are not record-enabled will be pre-rendered, even in a V-Rack. Plugins on the instrument tracks are NOT pre-rendered, whether they are in V-Racks or not.

The above assumes that none of the exceptions to pre-rendering are applicable. (See next post)

In the meantime, there's nothing wrong with running a track in real-time. Pre-rendering was most helpful back when we were using G4 Powermacs. With our current 4, 6 and 12 processor giants, it's a nice feature, but certainly not necessary for all but a few who are running giant templates full of active tracks.

Shooshie

[Shooshie]

Maybe it would be handy to print the list from the manual of exceptions to Pre-Rendering:

• • powered plugins such as UAD-1 effects, or TC Powercore effects.
  • Post-fader effects
  • mono-to-stereo effects
  • mono-to-surround effects
  • stereo-to-surround effects
  • any effects that follow the effects described above in the signal chain
  • any instrument track that has at least one record-enabled MIDI track assigned to it
  • plugins on Aux Tracks
  • any effect on an Instrument Track
  • any effect or VI whose interface window is open
  • any effect or VI for which you have chosen "Run this instance in Real-Time"
  • any effect or VI for which you have chosen "Default to Real-Time"

Those are, to my knowledge, all the exceptions to pre-rendering.
In other words, the above examples will ALWAYS run in Real-Time.

The list does not include VIs in a V-Rack. It is my assumption that VIs pre-render even in V-Racks, providing they do not also involve one of the above exceptions. MOTU Tech Support confirmed this twice (two different technicians).

One has to wonder whether some synthesizers could ever be pre-rendered, if they use random-like processing, or what about side-chaining? What if the side-chain source has effects in it, and the send is post-fader? My answer to these kinds of things: don't overthink it. If it runs in real-time, it's no big deal!

Shooshie

[dix]

Pre-rendering was most helpful back when we were using G4 Powermacs

Right. Since those days, using pre-render mode hasn't been that useful. Occasionally, if I'm right at the wall, turning on pre-gen on certain instruments or plugins will help, but it's rare.

You lose the ability to scrub or preview MIDI notes that are not on record enabled tracks. It also causes other random playback anomalies for me. For these reasons I usually keep everything in real time.

[Tritonemusic]

I used the term "pre-gen" simply because that's what everyone was using here. I'm fully aware of exactly how this works, semantics aside.

Quite frankly, I was too lazy to start typing a huge chunk of the manual when people could simply look it up. Also, I was referring to plug-ins (as mentioned in the title of the thread) and audio tracks, not VIs.

Hopefully, that clears things up.

[Shooshie]

I used the term "pre-gen" simply because that's what everyone was using here. I'm fully aware of exactly how this works, semantics aside.

Quite frankly, I was too lazy to start typing a huge chunk of the manual when people could simply look it up. Also, I was referring to plug-ins (as mentioned in the title of the thread) and audio tracks, not VIs.

Hopefully, that clears things up.

Oh, no offense intended! My post was edited multiple times. It started clearly separating your reply from others, but as I edited, it became more sensible to combine some things, so they just all got mixed together. Also, I was using pre-gen, too. I tried looking up pre-gen to verify that record-enabled rule, and couldn't find it in the index. Then I tried "pre-render," but it wasn't in the index, either. So, I went backward and tried "Run in real-time," and BINGO. Oh well, at least it's there.

As for the rule about record-enabling, the best I can find is that it only applies to MIDI tracks and their VIs. (V-Racks make no difference, either way) I asked MOTU Tech Support twice about audio, and whether a record-enabled audio track would pre-render. They said yes, it would. I still kind of wish Magic Dave would weigh in on the subject. There are some things that get really gray, the deeper you go, and this is one of them.



Again, pre-rendering is just a side-benefit these days in most cases. This isn't a show-stopper.

Shoosh

[Tritonemusic]

No offense taken, Shooshie. Sorry, my written words can come across as being practically the opposite of how I would come across in person. I have a lot of work to do, as far as that's concerned.

A good test as far as audio track and plug-ins are concerned:

Load an audio track with really taxing plugs. If they're not running in realtime, the CPU meter will practically be undetectable. Now, record-enable that track and watch that sucker spike into the read zone.

[Shooshie]

A good test as far as audio track and plug-ins are concerned:

Load an audio track with really taxing plugs. If they're not running in realtime, the CPU meter will practically be undetectable. Now, record-enable that track and watch that sucker spike into the read zone.

Yeah, that's what I used to do. Thought I had it all figured out, but there are so many variables, and only so much time. Turns out, I just had enough figured out to accommodate what I do. When people started wanting to know the exact rules, I finally just had to call MOTU, twice. Judging by their tone of voice, I suspect they are not sure, either.

Shoosh

[bayswater]

So if I route the output of a VI in a V-Rack to an audio track indirectly via an Aux, plugins on the audio track with monitoring on would pre-render as long as the audio track and the MIDI track are not in record mode. If so, it's hard to see why DP would not be able to pre-render the same plugins on the Aux that sits earlier in the chain.

[Shooshie]

So if I route the output of a VI in a V-Rack to an audio track indirectly via an Aux, plugins on the audio track with monitoring on would pre-render as long as the audio track and the MIDI track are not in record mode. If so, it's hard to see why DP would not be able to pre-render the same plugins on the Aux that sits earlier in the chain.

DP's programmers seem to design everything with a caveat. I wonder if they have meetings to determine the caveats they'll incorporate into new designs. Seems they could just program though them and not limit things. Sometimes I get a little tired of that. A feature sounds really cool, then you start getting into the gray area and fine print. (which is hard to find, or non-existent until we ask Magic Dave)
Oh well... it's a strange little app, but it's OUR strange little app.

Shoosh