Does GTL provide Link information to AUM?

edited June 30 in General Discussion

I'm writing with Bram Bro's support about the possibilities of Mozaic Plugin Workshop (https://apps.apple.com/us/app/mozaic-plugin-workshop/id1457962653) which allows to script inputs/outputs of MIDI signals. I will use this to create more advanced controls using my iRig BlueBoard.

I asked the support:

One more question though: is there a way how Mozaic can sync with my favourite looping app "Group the Loop"? It supports Ableton Link. The thing is that I want to very precisely (on the beat) trigger some action, so it would be great to configure Mozaic that it will execute triggers always in time on a beat. For example, when tapping "A" on my BlueBoard between two beats, the corresponding action should be triggered exactly on the 2nd beat. I feel that "MIDI clock" could be of use here?

It would be even greater if Mozaic could know about the current loop’s length, so it would be possible to trigger actions at the end of the current loop. But I think "MIDI clock" doesn’t go that far, right?

The answer was:

Mozaic is obviously limited to whatever the AUv3 standard supports. Link is always handled by the host, not the plugin. The plugin only knows the current beat and the current measure, because that's what the host exposes to AU plugins. There's no way for plugins to get access to Link information itself.

So does GTL provide any information like that to AUM when both apps are running side by side?

Thank you.

PS: Mozaic seems very promising. Some more details from the answer, just for the records:

I would not use MIDI clock myself because it's not that great on iOS (which is not a realtime operating system) and MIDI clock doesn't contain timing information. It's just a pulse at regular intervals, once you're out of sync you'll never get back in sync. If you want something to happen on exact beats then I would use the OnNewBeat or the OnMetroPulse (if you want to set your own interval) events to make something happen at sample-accurate times:

@OnNewBeat
if HostBeat = xyz
// do stuff on beat xyz
endif
@End

Similarly, if you want your Mozaic script to know about the loop length, then GroupTheLoop needs to send that information to the host in MIDI form first, otherwise there's no way for either the host or Mozaic to have this information. I don't know GTL, but I doubt it does that :-)

Comments

  • edited June 30

    Hi @josh,

    GTL and AUM share tempo and phase info via Ableton Link. So AUM does not know the individual loop lengths in GTL but it does know the general phase. Ableton Link phase allows the apps to keep sequences in time. For example, if you have two 8 bar loops they will start playing at the same time. As GTL can have many different loop lengths so only the longest even loops are reported to the Ableton Link session. It's possible to change this in Settings -> Clock Settings -> Sync Quantum. If you change the Sync Quantum to 4 bars, for example, GTL will always remain in phase with 4 bar sequences in other apps.

    Presumably AUM sends timing info to its AUv3 plugins so if GTL and AUM are phase aligned via Ableton Link this information should be relayed to the plugin in AUM.

  • This sounds promising. With "general phase" you mean when the current group "restarts" playing, right? And it's determined upon the longest loop in the group, correct?

  • edited July 1

    Yes pretty much although it's the longest loop playing, which also includes loops the master group. It's possible for GTL to fall out of phase with AUM/other Ableton Link apps if you have groups with different length loops in them and are switching between them. To avoid this you can set the "Force Phase Alignment" option in the Clock Settings. This will force all other apps to keep in phase with GTL.

  • Good to know! Thank you, Jack. I feel that I'm very close now to having set up everything I could ever dream of about live looping - and more and more possibilities seem to open up whenever I talk to you or the guys at Audiobus forums! :smiley: :heart:

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