Topic by matyas47

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Topic: Constant dropouts when running as a plugin in Bitwig on Linux

Hello,
I'm experiencing constants dropouts, clicks, and xruns when attempting to run Pianoteq as a plugin in Bitwig on Linux. I do not experience these issues if I run it as a standalone. Other software instruments do not give me these issues in Bitwig.

Configuration:
i9 32 core 5.4 GHz
32 GB RAM
Nvidia 4060
RME Madiface Pro

Pop!_OS with Pipewire
Pop!_OS kernel with rt-preemption and System76 scheduler
Audio group set, standard rt permissions/memlock settings/audio group set up/swappiness set to 10/irq threading enabled
Audio tasks set with nice to -19
Performance set to "high"
Wifi and Bluetooth disabled

Tried all buffer settings from 64 to 1024, 44.1 and 48 kHz sampling rates.

Other things I've tried:
Resetting audio driver after loading PianoTeq
Different USB ports on the computer (including via a Thunderbolt dock)
Disabling the Nvidia card
Changing polyphony settings.
Currently, no devices are connected except for the audio interface and a midi keyboard.

The performance tab does show a large variation in CPU usage. I'm nervous about adjusting CPU frequencies as this machine has a large number of CPUs and I'm concerned about overheating.

Reply by matyas47

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Re: Constant dropouts when running as a plugin in Bitwig on Linux

Interestingly, I discovered that there is problem with dropouts if I run Pianoteq as a separate app and route its output into Bitwig using Pipewire. With polyphony set to "pessimistic" and a buffer of 128, I have no issues and the latency is quite acceptable. CPU usage is low enough that I may even try a lower buffer setting.  I now suspect the issue may be more related to Bitwig than Pianoteq, but further testing is needed.

Reply by Luc Henrion

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Re: Constant dropouts when running as a plugin in Bitwig on Linux

matyas47 wrote:

Interestingly, I discovered that there is problem with dropouts if I run Pianoteq as a separate app and route its output into Bitwig using Pipewire. With polyphony set to "pessimistic" and a buffer of 128, I have no issues and the latency is quite acceptable. CPU usage is low enough that I may even try a lower buffer setting.  I now suspect the issue may be more related to Bitwig than Pianoteq, but further testing is needed.

Did you try other virtual instruments ? If you suspect Bitwig now, it might be interesting...

Luc Henrion's Website

Reply by matyas47

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Re: Constant dropouts when running as a plugin in Bitwig on Linux

Luc Henrion wrote:
matyas47 wrote:

Interestingly, I discovered that there is problem with dropouts if I run Pianoteq as a separate app and route its output into Bitwig using Pipewire. With polyphony set to "pessimistic" and a buffer of 128, I have no issues and the latency is quite acceptable. CPU usage is low enough that I may even try a lower buffer setting.  I now suspect the issue may be more related to Bitwig than Pianoteq, but further testing is needed.

Did you try other virtual instruments ? If you suspect Bitwig now, it might be interesting...

I am now quite convinced that this is a problem with Bitwig. Other VST instruments do give me similar problems in Bitwig. Meanwhile, I do not seem to have these issues in Reaper.

Reply by Luc Henrion

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Re: Constant dropouts when running as a plugin in Bitwig on Linux

matyas47 wrote:
Luc Henrion wrote:
matyas47 wrote:

Interestingly, I discovered that there is problem with dropouts if I run Pianoteq as a separate app and route its output into Bitwig using Pipewire. With polyphony set to "pessimistic" and a buffer of 128, I have no issues and the latency is quite acceptable. CPU usage is low enough that I may even try a lower buffer setting.  I now suspect the issue may be more related to Bitwig than Pianoteq, but further testing is needed.

Did you try other virtual instruments ? If you suspect Bitwig now, it might be interesting...

I am now quite convinced that this is a problem with Bitwig. Other VST instruments do give me similar problems in Bitwig. Meanwhile, I do not seem to have these issues in Reaper.

You can also run a test with Waveform (Traktion) to be completely sure.
https://www.tracktion.com/products/waveform-free

Luc Henrion's Website