Pops/clicks when crossfading (8.4.0~ds1)

[lightcoat]

I’m really loving Ardour but I’m running into a bug where 1-sample pops and clicks appear when using crossfades. I don’t understand the circumstances that cause them to occur, but they’re reliably in the same time location after bouncing.

Here’s an example. Please observe how the 2 regions overlap where “mark2” is.

[lightcoat]

After using the “Freeze” feature, observe there’s a 1-sample spike (audible) immediately to the right of “mark2”:

[lightcoat]

The same clip — this time I’ve dragged the region slightly to the left:

[lightcoat]

But after using the “Freeze” feature, the 1-sample spike is no longer there:

Any idea what might be causing this? Any workarounds? Thanks!

[paul (Paul Davis)]

I have a memory of fixing something like this between 8.4 and 8.12 …

[lightcoat]

An even simpler case… this is just 1 layer:

[lightcoat]

After freezing, the spike appears:

[lightcoat]

Oh, OK! I’ll try upgrading, then. Just using the default version from the package manager.

[lightcoat]

Hello, again! Thanks for your help. I’m testing with version Ardour 8.12.0 and unfortunately the bug still appears to be present.

Before freeze:

[lightcoat]

After freeze (transient pop immediately to the right of mark3):

[lightcoat]

Hi @paul, I have a small test project where the bug is present (unfreezing makes the spike go away, freezing again brings it back). Is there a way I can share with you privately?

[x42 (Robin Gareus)]

@lightcoat

After using the “Freeze” feature, observe there’s a 1-sample spike (audible) immediately to the right of “mark2”:

Is it always at the same location?

I just tried Ardour 8.12

1. New Session
   Audio time.
   Dummy back-end with Test-Signal Generator: DC offset [1]
2. Add New Mono Audio Track
3. Rec-arm and roll, Record 1 minute of Audio
4. Freeze track

With a flat-line (DC signal), a glitch to silence would be immediately obvious, but I don’t see any. Only region start and end fades:

and those also vanish when disabling region fades.

So there mus be something more to it. Can you provide a step by step recipe?

–

[1]

Available in debug builds, or optimized builds by editing ~/.config/ardour8/config
<Option name="hide-dummy-backend" value="0"/>

[lightcoat]

Hello, Robin!

Unfortunately, I don’t know the specific steps to reproduce.

But I do have a small Ardour project to share with the bug. Can I share it with your privately (direct message, email, etc.)?

It only happens in some locations, but once there’s a spike, it’s consistently in the same place until I reconfigure the region/fade lengths.

[x42 (Robin Gareus)]

@lightcoat

(direct message, email, etc.)?

yes, please robin@gareus.org and paul@linuxaudiosystems.com respectively.

[lightcoat]

Just sent! Thank you so much for your help.

[x42 (Robin Gareus)]

So far the issue eludes me (though the session helped find another bug).

When you unfreeze and re-freeze the track in the session does the click appear at the same position again? Here it does not.

[lightcoat]

Interesting! Yes, for me, it appears in the very same place after freezing again, unless I adjust something like the region boundaries or the fade lengths. Thanks again for looking into this.