Tempo sync AUv3 units using AUHostMusicalContextBlock

I am working on the development of an AUv3 delay plugin. Specifically I am working on the feature to sync the delay time with the tempo of the DAW.

Apple provides a feature for this called AUHostMusicalContextBlock :
https://developer.apple.com/documentation/audiotoolbox/auhostmusicalcontextblock

I found some example code here, on how I should retrieve that info from the DAW :
https://www.rockhoppertech.com/blog/audio-units-auv3-midi-extension-part-2-c/

( search for AUHostMusicalContextBlock within the text )

Using this code I can indeed get the tempo info from apps like Garageband and AUM.
However I cannot get the tempo info from Cubasis. The musicalContextBlock property is nil.

Am I correct to assume Cubasis does not provide an AUHostMusicalContextBlock?

Hi Asrodot,

Thanks for your message.
I will share this with our engineering and get back to you.

Best,
Lars

Thanks Lars.

I did some further experiments. I thought that maybe, when you enable Midi Clock in Cubasis, Cubasis will also send this Midi Clock to any AUv3 Send Effects. It would allow the effect to sync to the beat, although less efficient than use of AUHostMusicalContextBlock.

My AUv3 plugin is of the type “aumf” , or Audio Unit Music Effect , that is able to receive Midi data, as opposed to plugins of the type “aufx”, or Audio Unit Effect, that is not able to receive Midi data. And indeed, in AUM, when I enable the keyboard, it is able to send midi data to the plugin.

Not so in Cubasis. It seems Cubasis does not send midi data to any AUv3 Send Effect plugin. As a result it also does not send Midi Clock data. Can you confirm this?

Best regards,
Arno

Hi Arno,

Thanks for your message.
I’ve forwarded the feedback from our engineering to you via private message.

Best,
Lars

Many thanks,

I will look into it.

Best regards,
Arno

Hi,

I am developing AUv3 plugins and find myself in the same situation - Cubasis 3 does not appear to provide musical context info that would allow me to use the song/session tempo in my plugin.

Is there a solution to this? Other hosts (Garageband, AUM, etc.) provide the tempo as documented.

Thanks.

Hi bbfx,

Forwarded you the information from our developers via private message.

Best,
Lars