Labs bug: drastic exposure inconsistencies when using WBLK

[MariusMasalar]

Context

Running Labs firmware 2.10.70 on a GoPro Hero 11.

Camera settings:

• High bitrate
• 10-bit enabled
• Flat colour
• Sharpening low
• Fresh card (256GB Sandisk Extreme V30, formatted in camera)

Labs settings:

• WBLK=1
• WIDE=1 & 0 (tried both, made no difference to this issue)
• BITR=140 & 170 (tried both, made no difference to this issue)

The problem

When shooting with the above settings, the GoPro will progressively darken the exposure until it's almost completely dark.

This seems to happen in a couple of different ways, and the problem seems to manifest only while recording (exposure is stable until you hit the record button). It also seems to be affected by the presence of a face in the scene (in some of my tests, exposure darkens faster when a person enters the frame, or not at all until a person enters).

These are the two specific ways I had this manifest during my testing:

1. Exposure would sometimes darken progressively over the span of a few seconds, going from properly exposed to drastically under-exposed and then staying there. This is where it seems to happen when a face is in the shot because I was able to record a clip where the exposure stays correct until I entered the frame.
2. Exposure sometimes drops to black almost immediately, periodically fading back up over a second or so before dropping straight down to near black again. In this second version of the problem, the issue manifests as though someone were switching the lights off and fading them back on, and the pace of that switching accelerates until it becomes a literal strobe effect.

Additional details

I was able to reproduce these issues by simply applying and using the settings above. It doesn't happen for every clip, but it wasn't difficult to provoke and didn't seem to depend on location/ambient lighting conditions.

My guess is that it's related to the WBLK extension as turning that off seems to resolve the issue—I experimented with changing the other Labs settings but those didn't seem to change the outcome.

[dnewman-gpsw]

Confirmed. This is a bug.

[dnewman-gpsw]

Thank you for the detailed write-up.

[CyberoniOntoni]

I can confirm that WBLK causes same behavior on my GP 11. I hope it gets fixed in future release as I’m mostly shooting underwater :) For a meantime I’ll probably have to stick to Native WB.

[dnewman-gpsw]

Weirdly, it works fine on HERO11 Mini, same code.

[sanj3k]

Here are my metasettings and as you can see shutterspeed was locked, iso too but I have exposure changes going on in this video. This has to be connected to the WBLOCK flag

[shokwaav]

Sorry to sound pushy but is there an ETA for a fix for this? I'm wondering if I'll be able to use this for my dive trip in June.

[dnewman-gpsw]

No fix is likely coming, this is working on Mini (I think), but doesn't work on HERO11. As same code is applied, the fix is likely beyond the scope of Labs changes.