3

After I set QjackCtrl and Arour, I can record fine, but XRUN callback skips are annoying.

This is my QjackCtrl configuration:

In logs I see:

18:37:22.041 XRUN callback (97).
18:37:22.793 XRUN callback (42 skipped).
18:37:24.794 XRUN callback (111 skipped).
18:37:26.795 XRUN callback (111 skipped).
18:37:28.796 XRUN callback (111 skipped).
18:37:30.798 XRUN callback (75 skipped).
18:38:45.359 XRUN callback (552).
Mon Oct 20 18:38:45 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Running
Mon Oct 20 18:38:45 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:38:45 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:38:46 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:38:46 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:38:46 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:38:46 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
18:38:46.833 XRUN callback (3 skipped).
Mon Oct 20 18:38:46 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:38:46 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:38:46 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:38:46 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Triggered
Mon Oct 20 18:38:46 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
18:38:48.834 XRUN callback (23 skipped).
18:40:28.031 XRUN callback (580).
Mon Oct 20 18:40:28 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Running
Mon Oct 20 18:40:28 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
18:40:28.884 XRUN callback (1 skipped).
Mon Oct 20 18:40:28 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:40:28 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Running
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client PulseAudio JACK Source finished after current callback
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Running
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Sink was not finished, state = Running
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = PulseAudio JACK Source was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
Mon Oct 20 18:40:29 2014: ERROR: JackEngine::XRun: client = ardour was not finished, state = Triggered
Mon Oct 20 18:40:29 2014: ERROR: JackAudioDriver::ProcessGraphAsyncMaster: Process error
18:40:30.885 XRUN callback (32 skipped).
18:40:32.887 XRUN callback (89 skipped).

What are XRUN callback skips? How can I solve these problems?

Running Ubuntu 14.04 using low-latency kernel:

$ uname -a
Linux laptop 3.13.0-38-lowlatency #65-Ubuntu SMP PREEMPT Thu Oct 9 12:04:28 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
11
  • 1
    An xrun is a buffer overrun or underrun; you probably need to increase the frames/periods value. On my particular rig, I have to set up the sample rate, frames/period, and periods/buffer such that the total latency is at least 16 msec. Don't know if that's the right thing to do, but it minimizes the xruns by quite a bit.
    – John Bode
    Dec 22, 2014 at 12:36
  • @JohnBode Did you ever figure out if it was the correct way? Oct 8, 2015 at 16:15
  • @KarlMorrison I just added an answer. Probably it's a hardware limitation. Really recommend an audio interface (I'm really happy with Scarlett 2i2). Oct 8, 2015 at 16:16
  • @IonicăBizău I'm running a Scarlett 2i4 myself heh, probably not got it setup correctly Oct 8, 2015 at 16:32
  • @KarlMorrison Hmm, I just installed Ardour 4, QJackCtl, set up the QJackCtl options and started Ardour. Everything works as expected, no XRuns... Oct 8, 2015 at 16:36

1 Answer 1

8

Bumped into this again and finally have the correct answer to why xruns happen.

From JACKS page:

Specify the number of frames between JACK process() calls. [b]This value must be a power of 2[/b], and the default is 1024. If you need low latency, set -p as low as you can go without seeing xruns. A
larger period size yields higher latency, but makes xruns less likely. The JACK capture latency in seconds is --period divided by --rate

You need to set your sample rate, frames/period and periods/buffer correct. Below is optimal for usb devices.

(Frames [or buffer] / Sample Rate ) * Periods = Latency in ms

( 16 / 48000 ) * 3 = 1
( 32 / 48000 ) * 3 = 2
( 64 / 48000 ) * 3 = 4
( 128 / 48000 ) * 3 = 8
( 256 / 48000 ) * 3 = 16
( 512 / 48000 ) * 3 = 32
( 1024 / 48000 ) * 3 = 64
( 2048 / 48000 ) * 3 = 128
( 32 / 96000 ) * 3 = 1
( 64 / 96000 ) * 3 = 2
( 128 / 96000 ) * 3 = 4
( 256 / 96000 ) * 3 = 8
( 512 / 96000 ) * 3 = 16
( 1024 / 96000 ) * 3 = 32
( 2048 / 96000 ) * 3 = 64
( 64 / 192000 ) * 3 = 1
( 128 / 192000 ) * 3 = 2
( 256 / 192000 ) * 3 = 4
( 512 / 192000 ) * 3 = 8
( 1024 / 192000 ) * 3 = 16
( 2048 / 192000 ) * 3 = 32

I took the most optimal, all of them are here: http://wiki.linuxaudio.org/wiki/list_of_jack_frame_period_settings_ideal_for_usb_interface

1
  • 1
    That's cool stuff. Tho, in my case it was a hardware limitation I guess. By buying an audio interface, I solved the issue. Aug 20, 2016 at 21:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .