I'm getting flicker on an HDR timelapse which I think is to do with the way Lightroom handles SDR renditions of the image. As soon as I turn on HDR in Lightroom, I see some "false" flicker at a part of my timelapse which seems to correlate with a billboard in frame but outside of the reference area changing brightness. I've set the reference area to only include sky (there's an antenna from one building, but I don't think it has flashing lights). I've also pared down my edits to only be WB, exposure and contrast.

If I examine two frames that seem to have differing brightnesses in Lightroom, I see that the SDR rendition (either by viewing in the library or ticking "Preview for SDR Display" in the develop module) has some apparent differences in sky brightness, but the HDR rendition does not. I've noticed in other images that Lightroom's SDR rendition seems to try to be "smart", using contextual image information, like the other sliders which can cause flicker.

I've attempted to use 7.1 Beta and the option to disable proxies, but it does not seem to have an effect in this case.

Deflicker seems to do an OK job of adjusting things so that the SDR renditions match, but then there are discrepancies in the HDR renditions.

I only have an LRTimelapse Private license. I understand that the Pro license allows rendering HDR timelapse, but would upgrading to the Pro license also use HDR in calculating visual previews to avoid this false flicker?

I've attached screenshots which should show everything I'm trying to describe, but had to scale them down because of file size limits so I'm not sure if they're readable. Higher resolution at https://photos.app.goo.gl/V7CW6c8e3boG4GdP6 . I'm happy to provide more information if the fix isn't for me to upgrade to the Pro license.

Oh, I've just seen that contrast can cause flicker too -- I've just readjusted to 0 contrast and still see the false flicker when HDR is set on.

This is basically the old issue with sequences where the contrast changes between images and as you said Lightroom "tries to be smart". I call this "non linear" tools. I've explained this in my expert tips video #5, there are a couple of things you can do when editing to prevent or reduce this effect.
It's interesting to hear you don't seem to be experiencing the effect in Lightroom HDR Mode, however this isn't of help when deflickering because deflicker will be calculated from the SDR previews as you suspected.
Try changing the way you edit the keyframes (parametric tonecurve instead of the basic "blacks/whites/highlights/shadows" and use the Camera Standard profile and not the Adobe Color profile when editing, as explained in the Tutorial: https://lrtimelapse.com/tutorial/expert

This post was last modified: 2024-09-04, 10:20 by rcloran.

I’ve seen that video, and as I said I already have tried with only WB and exposure edits (no whites, blacks, shadows, highlights or tone curve). Unfortunately LR doesn’t yet seem to have camera profiles for this camera (Sony a7Cii) — I’ll try see if I can somehow get it to use the a7iv camera profile or something, or hopefully profiles will come soon ?.

I’m happy to provide sample raw images if it could help, but as far as I can tell because what I’ve seen of the non-linear behaviour of the SDR rendition in HDR mode, the fix might need to be in LRTimelapse. But maybe that isn’t an issue once I can get camera profiles ?‍♂️

Thanks for the quick response

This post was last modified: 2024-09-04, 11:09 by rcloran.

Oh, it does have the camera matching profiles, they're just named to match the in-camera "creative look" names which are ... strange. Does LRTimelapse set the profile in the initial XMP? Because LR showed an error when I first loaded the sequence saying that there was no "Camera Standard" profile -- the correct profile to use here would be "Camera ST". That error message was why I thought LR didn't have the profiles yet.

Anyways, the flicker is still there when using Camera ST (and no edits other than WB and exposure, not even animated).

I'm afraid there is not much I can do about this. This is how Lightroom works. However, personally I've never came around a sequence that I couldn't edit with the right tools.

I agree that it's not ideal that LRTimelapse can't access the HDR development to use it as a reference for deflicker, if Lightroom applies tools differently in HDR vs. SDR, but unfortunately that's how it is. There is no technical way for me to access HDR previews currently.

If that's what bothers you, you could do a flat edit, apply the deflicker, and then change the edit to your liking without deflickering again.

I spent a bit of time learning a bit more about how LRTimelapse gets the preview images, and I now see why you say there's not much you can do about it. I agree that it is a limitation of the current implementation, unless DNG Converter could be coaxed into generating HDR previews somehow.

I think I've found out how to avoid the non-linear behavior in the SDR rendition -- dial clarity in the SDR settings to -100 (instead of the default 0). I found this at https://www.reddit.com/r/Lightroom/comme...ngs_match/ and it seems to avoid this flicker. Might be worth adding to your documentation.

I think the SDR settings might not have been passed between frames during auto-transition, so I had to manually sync that to all the frames in the sequence -- it would be nice if these settings could be passed across or even animated.

This is very interesting! I'll pin your post to the faq and will do some more research by myself.