Ardour and Hydrogen playing loops

Hello everyone! new to Ardour (and I really like it!) and to forums.
When Ardour and Hydrogen are synchronized with Jack, (so setting sync from Int to -> Jack) I can’t play a section in loop anymore, because loop button is disabled, even if Hydrogen is not set to Master jack app.
It seems like Ardour is not acting as Master app

thanks!
bye
manu

Hi everyone! Any idea about this? thanks!

This is not possible. JACK transport does not support looping.


Tech details

This is a limitation of JACK and it is mostly intentional: To synchronize transport among many applications, one would have to establish if all apps support looping.

Furthermore JACK transport was designed to accommodate slow-sync clients that may need to read large amount of data from disk. So JACK transport has a state to wait for locates to complete. This makes it unsuitable for seamless-looping. Last but not least, the state is bound by block-size. It would have been possible to specify explicit loop points to applications, but that likewise has synchronization problems.

The general consensus is that JACK was superseded by LV2 for cases like this.

Hi, thanks for the reply, but something is not clear to me: before Ardour I was using Qtractor. The situation was the same: Jack, Qtractor and Hydrogen, with Qtractor looping and synchronized with Hydrogen, acting as master. So, I can’t properly understand when you say that “JACK transport does not support looping”… I was doing it with Qtractor

Qtractor seeks (or rewinds/locates) to emulate looping.

Ardour was able to do the same, but it falls apart as soon as you want to record the loop, or want seamless (accurate) looping without drift and without short silence gap at every loop.

It was removed (around Ardour 5.5), because users expected it to work reliably for professional production, and filed bug reports that cannot be fixed (due to JACK limitation).