Plugins use CPU when Waveform is paused

[JonasB]

I have a problem where plugins use CPU even when not playing anything back. Just opening an edit in a project and the CPU gets loaded. The plugins actually use a lot more CPU than when playing back the mix.

Waveform 8.2.7 on MacBook Pro core i7

As an example:
1. Create a new edit
2. Load a single wav recording
3. Add Master Mix on master bus
--> CPU consumption is constantly 34% (according to the small round meter) and opening the CPU monitor says 0% from both Master Mix and Audio File Reading
4. Start playback
--> CPU consumption drop to 10% (round meter), open monitor still indicates 0% on everything
5. Move Master Mix plugin to the bus of the single track
--> Same behaviour regarding the small round meter (34% and 10%), but opening the detailed view the plugin is constantly on 100% regardless of play/pause state

I cannot find any reason for this, am about to try a total re-install soon :-/

[Quick edit]: This happens regardless of which plugin I use, AU/VST/VST3/builtin. And before someone asks, I do understand that 100% means that there is just a single effect and that number changes if I put multiple effects on the busses. Just added the info if it might be useful for troubleshooting

[FigBug]

It's most likely CPU throttling. When your system isn't doing much, it slows the CPU so it doesn't run as hot / use as much battery. Therefore Waveform will need a larger percentage of CPU time to do the same amount of work.

If you want you can disable "Run Audio Engine When Stopped"

You can read about disabling throttling here: https://www.davidschlachter.com/misc/kernel_task

[JonasB]

No throttling in the way that your linked web page suggests. Disabling the "Run audio engine when stopped" is indeed a workaround to use when only mixing and not recording. It still feels like a bug, since I suppose that not every plugin should run haywire when the audio is stopped and this option is enabled?

[Peter Widdicombe]

Are you sure your CPU is actually being taxed, using some other source rather than Tracktion meters? I..e. the cpu might only be running 20% and Tracktion taking 15% of that; but within Tracktion BioTek might show that it's using 50% of the 15% cpu Tracktion is currently using.

[JonasB]

The CPU is being taxed yes. Activity monitor and terminal top command confirms this. There is one thing I noted now though, and that is when Waveform playback is stopped and reports e.g. 40%, then this corresponds to the same number in activity monitor %cpu column, meaning that the total User load on the CPU is ~10% due to the multiple cores. So unless the Waveform meter can go past 100% it seems like Waveform meter switches to measuring on a single thread when stopped.

Maybe there is some CPU limiting issue by Apple behind this, but I cannot think of which, kernel CPU time looks normal, the laptop is not running on battery etc so it shouldn't try to limit applications too much. Waveform is listed as "App nap"=No, "Requires high perf GPU"=Yes, "Preventing sleep"=Yes.

Regardless, the answer to your question is yes on the CPU taxing, the laptop is getting warm

[JonasB]

Oh, and no VST instruments or anything, these are just straight microphone recordings.

[klangbastler]

No throttling in the way that your linked web page suggests. Disabling the "Run audio engine when stopped" is indeed a workaround to use when only mixing and not recording. It still feels like a bug, since I suppose that not every plugin should run haywire when the audio is stopped and this option is enabled?

when "Run audio engine when stopped" is active, you should see just the same cpu-use in playback and playback stoppped. that is perfectly normal and how it is supposed to work.
many daws stop the audio-engine when playback is stopped, others do run it all the time (mixbus for example), which has some advantages, at the expense of constant cpu-use. this is not a bug, that's just how it works.

if this is not the case (same cpu for play and stop) and cpu-throttling is not the cause, i could be a denormal-issue or maybe some other mac-os mechanism going on in the background.
but as you describe it, it seems the cpu use is more or less constant as it should be when the audioengine is running. tracktion seems to change the readout of its cpu-meter in this case?

[klangbastler]

i have a habit of switching the audioengine off in stop mode, when vst instruments or melodyne are not used in the project.
my macbook is also getting warm

it would be great to be able to set a shortcut for this option!
there is a script to switch this on and off, can anyone give a hint on how to set a keyboard shortcut for an already existent script in tracktion?

[JonasB]

Thank you for the answers, very helpful. I obviously wasn't clear on that the plugins with audio engine active was still using the same amount of cycles as when no audio is playing through. You live and you learn

if this is not the case (same cpu for play and stop) and cpu-throttling is not the cause, i could be a denormal-issue or maybe some other mac-os mechanism going on in the background.
but as you describe it, it seems the cpu use is more or less constant as it should be when the audioengine is running. tracktion seems to change the readout of its cpu-meter in this case?

This is indeed the case, Waveform reports the percent usage of a single core when playback is paused, but when audio is playing the same meter reports the percent usage of all cores (including hyperthreaded ones). So it might just be a cosmetic issue.

i have a habit of switching the audioengine off in stop mode, when vst instruments or melodyne are not used in the project.

Do the audio enginge need to be running in the background for Melodyne to work properly? I used Melodyne in a project just now with the engine in stop mode...

[klangbastler]

Do the audio enginge need to be running in the background for Melodyne to work properly? I used Melodyne in a project just now with the engine in stop mode...

this was the recommendation on how to use melodyne in tracktion.
it may be related to melodyne being able to "play" single blobs, when clicking on them. a bit like a sampler instrument.
other functions of melodyne may also need the audioengine running, but i don't know the details regarding that.

[PierreG]

I may well have posted this on another thread, yet in case I did not, here it is in all it's glory. It's copied from the Tracktion - Waveform Facebook Group, where I first posted it via separate comments in that thread.

I've requested the devs add a warning to Waveform regarding Melodyne, which reminds users that you need to have the audio engine running to enable Melodyne features, AND have it not behave horribly. One also needs to have the Audio Buffers set low enough, or Melodyne will be broken and unstable.

FB Thread:
Another heads up, this time regarding Melodyne that comes free with T & W products. I just spent a good amount of time troubleshooting and resolving an issue where an edit in T7 that was previously in good shape, would no longer play audio normally. Playback sounded like drunk warbley chipmunks singing under water! T would also crash this edit if inserting a plugin. I suspected Melodyne, yet didn't immediately find the offending clip in the massive edit. I don't typically use it, so I'm curious why I had done so this time around. I also hadn't worked with this edit in many months, so I'd not immediately guessed that Melodyne was in the mix.

Looking through the T log file revealed a number of ARA related initialization messages around the crash time, some that looked normal, and some like errors. I know Melodyne uses this extension, so this helped point me to it. I eventually found the clips that had Melodyne strapped to them and simply set them to use Elastique pro. The audio issue didn't go away until I selected another sound card in the settings tab, then reset it back to my ASIO interface. I think changing audio buffer size would also have cleared up the audio, after removing Melodyne from the clips that is.

During the troubleshooting process, T crashed many times, and I even lost connection to my Firewire ASIO interface (RME Fireface 800) while messing with the edit.

In short, Melodyne can cause incredibly intense and bothersome issues with edits, so be warned!

Addendum: I forgot to test whether or not lowering the audio buffer setting would have resolved the Melodyne enabled clips without removing them. T devs recently hipped me to the fact that Melodyne does not function well, or at all if the audio buffer settings are too high. I typically have mine high as to minimize audio glitches. Hope they can sort this out going forward.

Sorry for the one man conversation, just verified that if I lower audio buffers from 1024 to 512, Melodyne runs great. Another heads up = you need to have option - Run Audio Engine when Stopped - enabled in order for Melodyne to function properly, including hearing notes when you move them in the GUI. I should be done now. Hope this helps others!

Resolved (I hope!): After constant crashing of this edit, I finally found the last hiding Melodyne clip and removed it. So far it's behaving...

Resolved - v2.0: Although I was able to remove Melodyne instances from the edit, it was left constantly crashing in T7. It was stable in Waveform 8, yet the transport was super sluggish, as if it was working hard in the background to stay afloat. I also noticed that Windows System Interrupts were using 40% CPU, which is not right This resource reflects the ASIO Fireface audio interface's I/O load, which normally hovers around 13%. Decided to remove all VST plugs from the edit, and after doing so the edit was crash proof and running like lightening in T7 and W8. Reinserted all plugs in T7 and it remains flawless and snappy. Will pass this along to the devs.

* Not posted on FB:

One of the crashes Blue Screened Windows 10.

At one point I started getting plugin failures in the logs, from plugs that never have issues. It's like some common VST element was badly broken. Perhaps to do with Melodyne's ARA tables?

During the troubleshooting process, I did remove Melodyne from both T7 & W8.

[JonasB]

Very valuable information on Melodyne, thank you very much!

[tonedef71]

Another heads up, this time regarding Melodyne that comes free with T & W products. I just spent a good amount of time troubleshooting and resolving an issue where an edit in T7 that was previously in good shape, would no longer play audio normally.

Thank you for sharing the extensive account of your troubleshooting with Melodyne. I have a feeling this will be very useful to me later.