Brad - Feature Request - Offline Rendering

Dear Brad,

I’m really enjoying the efficiency both workflow wise and CPU wise of Cantabile and have set up Cantabile Solo on my Sony Vaio i5 laptop to use in my studio for recording VSTi parts into my primary DAW PC, an older but still perfectly adequate Q9450 quad core desktop rig I built nearly a decade ago.

REAPER is my DAW of choice (I’m an old ProTools refugee) and I’ve worked quite closely with the devs and the REAPER community in beta testing new versions and suggesting new features (some of which they’ve implemented) over the years. My username on the REAPER forum is ReaDave if anyone else posts over there.

REAPER is a fantastic DAW and is extremely efficient CPU wise but Cantabile definitely has the edge when it comes to dedicated VSTi hosting. I’ve also found the MIDI recording in Cantabile to be slightly more accurate despite the extensive MIDI tweaks the devs have done in REAPER recently which have made REAPER much better MIDI timing wise.

My current workflow regarding Cantabile and REAPER is to feed the audio output of the Cantabile PC (just a mini jack signal as a timing reference) into an input on my RME Fireface UFX and also record the MIDI and audio in Cantabile simultaneously (that is my primary reason for purchasing Cantabile Solo). Then, I import the MIDI and audio from Cantabile into the REAPER project and align them by hand. I can then edit the MIDI if necessary and render that track in REAPER using the same VSTi and patch in offline mode to obtain the best audio quality. REAPER does seem to have some issues doing this though and it doesn’t always accurately render the audio from the MIDI regardless of buffer settings and other tweaks.

What I would really like to do is to have the option of rendering the MIDI to audio after recording (the equivalent of offline rendering in REAPER) directly from Cantabile. That way, I could for instance, record a part using u-he Diva in draft mode then once I have the take right, switch Diva to divine mode and render the MIDI directly from Cantabile to audio ready to import into REAPER. I know I can just record the audio output of the VSTi whilst Cantabile plays back the MIDI but that still limits me to the realtime processing capability of the CPU. I often run out of CPU whilst playing back synths like Diva for instance with lots of polyphony and complex patches (quite a frequent occurrence in my studio) in Divine mode. Offline rendering would solve this issue.

So, to sum up, would it be feasible to add an offline rendering mode from MIDI to audio in Cantabile Solo and Performer?

I’m not clear myself what you mean by an “offline rendering” mode. Do you mean something like “freezing” a MIDI track to an audio one internally and not in real time? (Like Cakewalk’s Sonar does?)


Yep. That is exactly what I mean. REAPER also has a track freeze option along with the offline render to new stems. Both do very similar things. The render option copies the track first and renders the audio to that, leaving the original alone. Freezing simply applies all FX to the selected track, rendering to audio and removing all FX.
I prefer the render to new tracks option because it is easier to go back and have a look at the original track if I need to without unfreezing first. I usually render the track to a new track and then hide the old one and put its FX offline.

I think that what you’re asking for is, essentially, something that we were discussing back in Cantabile 2 days; namely, a Cantabile plugin.
That would take care of all your issues in one fell swoop if it’s primarily Cantabile’s architecture that you’re looking to employ.
If your issue is all about CPU then I guess you’re talking about recording your midi in Cantabile and having the playback of that midi file occur in a render mode - which is a very ‘DAW’ centric kind of function for software that is looking to provide the leanest, most streamlined, unbloated, software for use in live situations.

I can absolutely see the benefit of Cantabile as a plugin. No reason why such a thing can’t work if plugins like metaplugin can do it.

One other thought for an approach that could work right now, is to use loopMIDI to hit Cantabile from Reaper. Use an audio networking utility to get the audio back into Reaper.
Use draft mode.
When you render, place DIVA in divine mode and put the asio buffer up to lower the CPU drain.

Thanks for chiming in with your thoughts and suggestions Ade.
The bottom line for me really is I need to build a new PC. I do have that in sight and will probably be putting my Mackie ONYX 1640 firewire mixer on eBay to help fund things.
What I am really looking to do though is to work around the CPU limits of the gear I have right now. Both my PC rigs are fairly close in CPU capability and that is right at the limits when using a single instance of synths like Diva with complex patches and 16 notes polyphony in divine mode. Being able to offline render directly from Cantabile would solve this completely.

Even tweaking the buffer settings still leaves me with glitches in real time audio from the CPU heavy VSTi patches I sometimes use.

Perhaps I might just have to find out what is causing the inaccurate rendering of these synth parts in REAPER. It doesn’t happen on all synths though or all patches on the same synth. It doesn’t even happen in the same place during different passes at rendering.
It’s a bit of a mystery (now that I’ve said that, I’m going to have a certain Toyah song stuck in my head!!)

Hi David,

Thanks for the insight into what you’re up to. Surprised to hear Reaper has these MIDI timing issues and personally that’s what I’d be chasing down first as that’ll give you the best work flow if you can sort it.

In the meantime, Cantabile 2 has an offline rendering mode which might help - it’s one of the few features from v2 still to make it into v3. (Morph/Randomize being the other).


PS: here’s the Trello card for offline render if you want to vote on it :slight_smile:

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Thanks Brad. Great to hear the offline render has actually already been done in the previous version. I guess my license for V3 will work for V2 as well. I’ll download it and give it a shot.

Perhaps I should’ve clarified the rendering issues I’ve been having with REAPER. Upon re-reading my posts, it appears I was talking about the timing being the issue with offline render but it is actually a note velocity thing. Some notes get randomly rendered at maximum velocity. There are a couple of preferences in REAPER that I will experiment with regarding it notifying plugins of offline rendering state.

The trello thing is new to me. I clicked on the link you put in your reply (using my phone to type this) and got a screen with some info that didn’t seem to do much. When I returned here though, I noticed a counter next to your link and it had increased. Does that mean I actually voted for this unknowingly?!

Apologies for my newbieness regarding trello. Perhaps it is just my phone browser making it look a bit foreign.

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Quick update…
I tried multiple times today to reproduce the velocity problem rendering tracks offline in REAPER but initially couldn’t reproduce it. Then I opened Diva and saw it had defaulted back to multi processor mode off and quality to great rather than divine. Those were the particular patch defaults. I then turned on multi processor and divine modes and did a render.
All was good.
I then tried placing the plugin offline and back online, reset the MP and quality modes and immediately did a render. The first note was LOUD!
It seems the issue is when putting Diva offline and back online then rendering or even the first playback after putting it back online.

I’m not sure if it is a Diva issue or a REAPER issue but the workaround is to press play at least once if I have changed the state of Diva first (offline to online).

I’ll try this later in Cantabile with Diva and see if I can reproduce the same issue. That should tell me if it is Diva or REAPER.

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Well it’s a different serial number but you can get it by logging into to your account (using your v3 serial number) and then click on your v2 license to see the serial number.

No - that’s just a counter in the forum software for how many times a link has been clicked on. Not sure why Trello wouldn’t have appeared correctly for you - it works in most browsers I’ve tried.

Cool - let us know what you find.


Thanks heaps for the info Brad.
I haven’t had a chance to play around with Diva alternating between offline and online in Cantabile yet so don’t have any feedback just yet.
However, it does seem that recording the MIDI and audio in Cantabile and audio in REAPER (so I have a timing reference with the audio to line up things) and then exporting MIDI from Cantabile into REAPER and rendering in REAPER is now a working thing. It is indeed a better workflow.

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