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rosegarden MIDI app needs RT kernel?

Posted: Sun Oct 27, 2019 2:56 am
by hippie403
I've been playing around with music software on RPi 4B, rosegarden seems to be working OK for MIDI sequencing, but I noticed it has been displaying a warning about timer resolution and it suggests switching to a RT kernel. I assume they are talking about a kernel built with the rt-preempt option. Is a pre-built RT kernel package available for Buster/Pi4?

Re: rosegarden MIDI app needs RT kernel?

Posted: Wed Jul 22, 2020 6:31 pm
by JovianPyx
Same question about an RT kernel or other solution to the low resolution timer problem.

I needed a way to make sequences for practicing physical instruments. A simple percussion track and a bass track over which I can play/practice stringed instruments. Rosegarden works, but I see the warning and have wondered the same thing.

I've only started to work with Rosegarden, so I've not had a chance to get something laid down and listen to it for jitter or bad timing. Can someone say how bad it is?

Re: rosegarden MIDI app needs RT kernel?

Posted: Fri Jul 24, 2020 5:42 pm
by JovianPyx
I've had a day or two to use Rosegarden running under Raspbian to make practice loops on a Pi4B 8G, ondemand overclock to 2000 MHz, USB HDD root filesystem.

Perhaps I'm not that exacting about precise tempo settings, but I didn't experience anything I would call off or wrong. The beats I hear sound accurately placed, so I'm very happy with Rosegarden running under Raspbian buster with it's standard kernel.

My internet readings claimed a timer frequency of 100 Hz from one source and another claimed 250 Hz. I have no clue which is correct, but the timer's low frequency is said to be the cause of the low resolution.

Re: rosegarden MIDI app needs RT kernel?

Posted: Sat Jul 25, 2020 1:09 am
by hippie403
I have started using MusE instead of Rosegarden. No problems detected yet. I built the latest MusE 3.11 from github source. MusE seems a bit more "light weight" and more suitable for my purposes. Running on a 4GB Pi4 with USB SSD, standard clocks.