Black triangles in recorded waveform : xrun?

Hi !

I’m using Ardour 6.9.0 on Ubuntu 22.04 LTS with the “low latency” kernel.

Recently, I’m seeing black triangles my recorded waveforms :
black_triangle

Of course, most of the times I can hear a recording problem (blank or digital noise) where there is a “black triangle”. Another strange thing is that most of the times (but not always), these black triangles are just on the beat, or on half beat…

I cannot see any xruns in the ardour log (icon on top right of the UI). And previously xruns where yellow markers on the timeline.

Is this a new way for reporting xruns ? If no, what is it ? I searched the doc but did not find anything…

I upgraded my Ubuntu OS recently and previously with the very same hardware and Jack config, I had very few xruns… And now I have those black triangles very often…

Thank you for your help !

Answering my own question…

Looking at QJackCtl logs (messages), I now see a lot of xruns occuring… These xruns coincide with the black markers so I guess I find out the meaning of those markers…
I thought xruns were reported in Ardour log but it’s not. My bad…

Now I have to figure out why so many xruns are occuring, but this is another story…

Yes, they are x-runs.

The yellow markers on the time-line are helpful when recording, but as soon as you start editing and move regions around, the global position information is no longer useful.

The dropout is recorded and the sound-file has a discontinuity, so it makes sense to mark the location in the actual file source.

You can have both:

  • Preferences > Editor > Show xrun markers in regions
  • Preferences > Transport > Create markers where xruns occur
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