Blackmagic Forum

Hi Folks
I have been seeing this issue across all release versions of DVRS 16. Basically I prefer to use this below to simulate a blink-cut as a transition as its faster and easier (I do not remember what this is called hence the screenshot):



Basically I drag the clip ends back 'n' frames at each edge.
The problem also happens with other transitions I drag and drop to center on the edge of two clips.

It plays fine on timeline and after export without DVRS built-in NR as well as without enabling Neat Video Pro NR. However after enabling either version of NR the export displays a glitch at each clip transition - basically the exported file has a jump-glitch going back one or two frames then jumps forward to the the last/next frame that was being played back before the glitch. This happens at every clip transition but not in every export session - meaning I am lucky to get an entire series of smooth transitions across the full timeline on 2 out of 5 exports.

Right now a 3hr export session is wasted as I need to redo the export, take a chance and hope for the best again. How do we debug this?

The screenshot doesn't help me, and I'm lost.

Here is a 15 second clip showing the problem.
As a result I have been unable to upload content for a few days now (3 export attempts each 3hrs) and now I plan to get rid of the transitions until I find a resolution.

OK. The transition is called a Dip to Black.

To clarify, how are you arriving at that? Are you using the Dip To Color Dissolve? Some other way?

Simply by dragging the tiny white button/handle at the end or start of a clip back or forwards a few frames. But it does not matter whether I do it this way or if I drag and drop a prebuilt transition like dissolve to centre in between two clips.

I suspect the glitch happens when some of the clips use superscale (I do it because I zoom in sometimes) but then it also seems to happen randomly on the timeline on non-superscaled clip transitions. However I am confident any clip set to superscale triggers this glitch in the timeline.

Got it.

Nothing is jumping out at me that might cause this. I don't see it in my own work.

One possibility is your source media. What format? From what camera?

This is Hero3+Black footage Protune flat low sharpening. Currently I use NR+Sharpening using Neat Video in Pre-Clip followed by a ColorSpace Transform in the first node of the clip section where I do the rest of the color tweaks in subsequent nodes and end with a final ColorSpace to Rec.709 in post-clip...

Importantly I see this also with DVRS NR when I apply NR at the last node without pre-post set of nodes ...

Try moving all the effects to Clip nodes. You can use Shared Nodes if the effect (and it's settings) needs to apply to multiple clips.

It looks like an incorrect frame is being inserted from around the same area in the source clip.
Try turning temporal NR to off, only using spatial NR. That may reveal if the temporal NR is pulling in an incorrect frame.

Peter Cave wrote:It looks like an incorrect frame is being inserted from around the same area in the source clip.
Try turning temporal NR to off, only using spatial NR. That may reveal if the temporal NR is pulling in an incorrect frame.

This sounds plausible. Unfortunately I am unable to replicate this with a 15sec timeline - whether I move the Pre-Clip NR Node into the Clip section or not. Once I can replicate I can test with Temporal NR off.

My next project and I am suffering the same delays - I completed the timeline 3 days back but multiple renders have failed to be glitch free. The timeline looks visually jarring without any "fade to black" or similar transition, so I don't want to use that option. My last project came out looking somewhat dissonant due to removing any transition effects.

The challenge to moving the NR node from Pre-Clip to CLip section on the production timeline is this:

1. Resolve has "Append Node to selected clips" menu but no "Prepend Node .." functionality
2. I have many dozen short clips and executing "add serial before" + CTRL+V on each clip is too laborious
3. In any case I cannot disable Temporal NR for the final production export as the results are horrible.

Question to BMD developers - is it possible to setup my desktop Resolve installation for debug data collection while the export is in progress then identify the exact short sequence of frame numbers experiencing the glitch and work your way backwards? This is a home desktop not office unit and I can play around with it a bit.

did you try to have the original clips, NR taht, compound clip that, than do the dissolve/dip to black and color?

G0bble wrote:The timeline looks visually jarring without any "fade to black" or similar transition

As a viewer, I would disagree. In the example you posted above, I find the transition distracting and inappropriate for the scene. A Dip to Black signals to the viewer a significant passage of time. It's weird when you use it just to avoid what may be a jump cut. There are better ways to handle that.

G0bble wrote:Resolve has "Append Node to selected clips" menu but no "Prepend Node .."

It's not required to put NR early in the node tree. I typically do it last.

Are you using image stabilization on that footage, there's seems to be some tell-tale warping? Agree on the inappropriate use of a fade, which I've always seen as a temporal thing too - maybe that's what you trying for?

I second Steve's comment on the warping. That, too, is very distracting.

A quick blink of an eye is what I am trying to simulate. My movies are just discrete 5-60sec clips from UW vacation footage that I stitch together on a timeline and the "blink" looked the easiest. There is no continuity or story to my timeline except recording a days diving with interesting captures. Without that blink it simply looks worse with a sudden startling jump to next clip ...

I may have faded more frames than I normally do in the demo clip - in any case I have seen the problem even with ready-made transitions that I drag and drop to the timeline.

I do make heavy use of stabilization as my camera is a Hero 3+ Black with no stabilization and the footage is very shaky when I am finning and shooting - usually constantly on the move, rarely still for less than a minute at a time, as I have to cover a lot of ground from point A to B and never re-visit the same site again on the same vacation for dedicated/repeat shooting. I shoot wide to overcome that - and let the stabilization do some heavy cropping of the edges.

The warping effect is weird and I have been able to tone it down by using "Similarity" over "Perspective" in the Stabilization settings but its still there ... if you have tips on how to prevent that I would love to hear them. I wonder if that is similar to a rolling shutter effect when I pan the camera? Let me test with ProDad software before importing into DVR - it has corrections for that specific case IIRC.

As for NR - applied at the end of heavy color grading of the raw flat/protune footage turned out quiet ugly in my ad-hoc tests over many clips - I prefer doing it before all the rest of the nodes and quiet satisfied.

PS: I managed a successful export to 1440p without upscaling the original 2.7k timeline to UHD and I suspect this is the one thing that is messing up and causing the glitch. I was exporting to UHD hoping that YouTube will encode to a better format but I guess I will skip that. I have a small correction to do that I overlooked in the previous export and the repeat export will tell if the glitch-free outcome is stable.

I can almost guarantee that if you remove the image stabilization then the fades will not glitch. Excessive IS in post produces the warping that is seen in your footage and depending on where in your chain you applied it is causing the glitch.

Steve Fishwick wrote:I can almost guarantee that if you remove the image stabilization then the fades will not glitch. Excessive IS in post produces the warping that is seen in your footage and depending on where in your chain you applied it is causing the glitch.

If I apply IS in Edit timeline how do I ensure it is applied last? I guess Color tab with IS applied in last node is one way?

What is probably happening is that you are applying a combination of FX at the same time, e.g. IS, NR and a fade then rendering. As the shot fades in or out, the IS loses it's reference points, more noticeably on the fade in since it is taking time to establish them in the first place. Therefore I would apply only the IS to the clips you need, then render that out as sub-clips and use these for further FX processing in your edit.

I personally would find that level of IS, you have used unacceptable, so would try a less severe balance. In the end there is a limit to what you can do with a very unsteady shot and an alternative shooting method is the only answer.

Steve Fishwick wrote:What is probably happening is that you are applying a combination of FX at the same time, e.g. IS, NR and a fade then rendering. As the shot fades in or out, the IS loses it's reference points, more noticeably on the fade in since it is taking time to establish them in the first place. Therefore I would apply only the IS to the clips you need, then render that out as sub-clips and use these for further FX processing in your edit.

I personally would find that level of IS, you have used unacceptable, so would try a less severe balance. In the end there is a limit to what you can do with a very unsteady shot and an alternative shooting method is the only answer.

I doubt that because I do IS before I fade-to-black the ends of the clips (one of the last things I do before I export). Once IS is set, it should not be affected by what I do next - unless IS tracking is recomputed during export render - is it? If so I will try your suggestion of round-tripping after IS after I am done with my prioritized projects someday (combined with upscaling source timeline).

For now - I've actually had a flawless 2nd export - by not upscaling the timeline over and above the source footage resolution - so I think that what it might be - or rather as you mentioned the combination of upscaling with everything else thrown in the mix (Of course the warping is a different matter -since these are not professional projects I am ok with 1-2 seconds of warping every minute).

The Gopro is a very portable lightweight camera setup with the tray and mini video lights and making it heavy by adding weights and balance it for neutral buoyancy is not on my to-do list - I plan to get a 1" sensor camera someday with a larger body and perhaps I can achieve better IS out-of-box with a heavier setup some-day. For now it is what it is.

Thanks for the inputs so far everyone.

Cheers