OK, looks like it's a bug.

Sony X-AVC 4K source from an older RX100. Add to timeline in 32-bit video project, add color curves fx at the clip level, drag the curve so the shadows darken, then just walk through the frames, and individual frames will randomly darken. Workaround is render out to an intermediate in a different codec. I created an HD intermediate using the Sony AVC template, and that at least did not display the same flickering.

What source media are you using? Is it 8 bit or higher video? What color space was it shot in? If you don't know these things, download mediainfo and post the report it generates for your media here.

The question was about the bit depth and color space of your camera source. If you're not sure, use MediaInfo.

https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/

It's a bug, not confusion about media bit depth

I work pretty much exclusively with video-level media with projects set to 32-bit and have seen a similar issue with clip fades... I noticed when a key-frame is at the exact end of a clip-fade (snapping enabled), that there might be a level drop at that specific point. This throws off my setting any animated level-adjustment fx controlled by that keyframe. Doesn't seem to happen if quantize to frames is left on all the time. I think because that forces the fades to end at frame boundaries and keyframes to snap to an exact no-fade point.

It's a bug, not confusion about media bit depth

Suit yourself. "Confusion" would only arise if one were placing 8 bit integer source in a 32 bit float project.

It's a bug, not confusion about media bit depth

Suit yourself. "Confusion" would only arise if one were placing 8 bit integer source in a 32 bit float project.

I appreciate you have you own ideas about how math works. I don't share them.

I can replicate this with footage from my Sony A7C also. I'm attaching a screenshot of the media properties.

To replicate the bug:

put a clip on the timeline. set project settings to 32-bit video. set preview setting to best-full. add color curves fx at clip level and drag the curve to darken the shadows. using the arrow keys, scrub through the clip. For me, this results in a dramatic random brightness shift -- almost like a levels conversion is happening randomly at the individual frame level.

So far, I have not been able to replicate this with any of the Vegas render templates, including XAVC and Main Concept AVC

@ALO

I used XAVC UHD from a Sony RX10-IV in a 32bit video level project to follow your instructions.

It happens.

I make no representation about what it is.

I got some rx100 XAVC-S 8-bit footage from a friend, and the behavior is not evident in 8-bit projects, at least with that sample.

I got some rx100 XAVC-S 8-bit footage from a friend, and the behavior is not evident in 8-bit projects, at least with that sample.

Yes -- not happening when project properties set to 8-bit.

This is some kind of interaction with 8-bit XAVC, the color curves fx, and the 32-bit video levels project setting.

I'll keep playing with other 8-bit formats to see if I can get it to happen with something other than clips from my Sony cameras.

Interesting, does it also happen with color curves in the color grading panel?

I tested with X-AVC S media from the RX100IV (1080p) on a 32-bit video levels timeline with Vegas 19.550 and don't see an issue with playback or scrubbing through a frame at a time. NVENC render looked fine.

With a6600 X-AVC S UHD media on 32-bit levels it seems okay with preview/auto. With best/full it keeps blacking out as my laptop can't keep up. Scrubbing frame by frame I couldn't find problems. NVENC render (1080p) looked fine.

My system details are in my signature (XPS 9560) in case this is a video card/driver specific issue. I'm Intel/NVIDIA here.

Interesting, does it also happen with color curves in the color grading panel?

Roger what a great question! I just checked and it does *not* happen w/curves in the grading panel. So there's a workaround.

For me, the flickering occurs even just dragging the fx color curves handle around (and changing the contrast levels). I am using an NVIDIA GPU (RTX 3050 Ti Laptop) which is quite powerful.

This issue persists in the current build (326) -- the source media is a Sony XAVC 8-bit clip from my RX100 M5.

I think it's directly related to the Color Curves fx (the plugin, not the curves in the color grading panel). The CC fx may also be responsible for the brightness flickering I'm seeing working with 10-bit HEVC footage.

If it would be helpful, I can post a link to a test clip from my RX100, but I believe others were already able to replicate this.

If you don't want to scroll through above, the issue happens when 8-bit XAVC is placed on a timeline with project properties set to 32-bit video levels, and a CC fx is applied at the clip level.

This issue persists in the current build (326)

I'm not seeing that when I try to follow your steps ( I hope).
Look when trying on my laptop

I'm going to try to see if I can replicate this on several other machines, and esp with footage rendered directly out of Vegas. Those RX100 files are from an old camera, so this may otherwise not be worth pursuing...

I can replicate this on my other machines (which have different GPU's), but only for the Sony RX100 clips. 8-bit Sony XAVC S from my FX30 works fine. So I can live with that.

The RX100 M5 is a relatively old camera (2019ish?), and maybe there's something funny about those old files. If this appears with any other format I use, I'll make a note of it, otherwise probably nothing worth bothering with here.

@ALO, are you able to place such a short file on a webshop so I can download it to do the same test?

Yes, please post a sample, we will all test it, determine what the common factors between the machines showing the issue are, and that will give the development team a nice head start towards figuring out the source of the problem and getting it patched.

I am seeing a variation of the problem using footage from my A7C. For me, I see black frames.

This is frame 217

Frame 218

Frame 219

Frame 220

Only happens with 32b project. 8b is fine.

GPU driver version?

I will update and report back

Edit: same problem after update

I am seeing a variation of the problem using footage from my A7C. For me, I see black frames.

This is frame 217

Frame 218

Frame 219

Frame 220

Only happens with 32b project. 8b is fine.

Does this involve the Color Curves FX on the clip, or does it happen without ? I will upload a clip of my RX100 M5 so others can test, and I'll also put together a short screenshot video of what I do to trigger the issue