Blackmagic Forum

Need some brain power. Upon rendering the video shows random pixel clusters across what are supposed to be several blank (black) segments where the video cuts to black between clips. Everything looks clean in EDIT. Nothing in FUSION. These pixels only show post render.

The pixelation first appeared on several black segments, but has since morphed to a neighboring title clip. This is occurring in a section that contains just stills captured via DR's EXPORT on the COLOR page. Total pixelation size can be up to 10% of the screen (see attached).



If I layer a video clip over the affected area the pixelation goes away. Same if I insert a still into the blank (black) segments. No pixelation. It only appears in predominantly black clips. Here's what I've done so far with no positive results:

- placed a solid black in the affected areas (instead of simple using dead space)
- created a solid black background in FUSION
- moved the solid black color to another track (above and below)
- moved all clips to another track and deleted the original track
- moved the whole project into a new section of the same timeline
- exported then imported the project
- rebooted DR
- rebooted the desktop
- tried various formats and codecs (MOV, MP4, H.264, MPEG)
- toggled on/off several of the advanced options

Nada.

Am new to DR but first time this has happened after 1/2 dozen other projects. Any thoughts on problem/solution?

Using Windows 10, DR 16.2.0.054, GeoF 1070.

Thanks in advance.

MOV is not a codec. Did you try Cineform or DNxHD/HR?

Use the Native encoder, not nVidia?

Uli & Jim, thanks for the quick replies. Here's are some additional clues:

Interestingly the pixelation ONLY shows when viewing a finished piece outside of DR. When viewed within DR (whether using H.264, Cineform, DNxHR, DNxHD or MPEG) none show any pixelation. When viewed external to DR (H.264 and MPEG), the pixelation is present. That pixelation also transfers to YouTube, thus I'm ruling out a workstation issue(?).

So the search for the cause/solution continues.

Please make sure you are running on the latest nvidia drivers.
If the issue persists, can you also send us a sample project which shows this issue? and a captured log from your machine.

more details here - viewtopic.php?f=21&t=90190

Hi, I'm getting exactly the same problem. However, the glitchy artefacts are appearing only on predominantly pure-white fast-moving transitions as per the image attached. (anything circled by the red line should be white).

This is happening when I'm playing the MP4 video outside Resolve on VLC and Media Player (win 10). It plays without any glitches within Resolve. I have the latest version of Resolve.

I have a fairly urgent assignment I need to submit shortly, so hoping you can help me resolve (!)

Responding to Jim's earlier question re: use of the video player or NVIDIA settings, pixelation happens in either scenario. Latest content creation drivers are loaded for the 1070.

If you are under a tight deadline, this might be a workaround: export DNxHD/HR instead and to the final compression with Handbrake or a similar tool.

Update: Pixelation revealed itself on another project, this time in a regular video clip. Deleted that clip from the timeline, reinstalled the same clip, rendered project - no pixelation.

On the original project where the pixelation was persisting in a few of the black segments, the only way to fix it was to sub the black with a video clip or still.

So now I'm leery as to when and where this anomaly will resurface, and to what extent I will have to redesign the project to recover. Would be nice to have more consistent results.

Yuke17 wrote:On the original project where the pixelation was persisting in a few of the black segments, the only way to fix it was to sub the black with a video clip or still.

Do you mean pure black, like 0,0,0 or video legal black 16,16,16 or the equivalent in 10 bit?
I would expect encoding troubles with illegal black in a codec set to video range.

"Black" meaning either the native black present from a gap in the timeline, or inserting a solid black from the Generator. And the pixelation can present itself when either dragging the solid black Generator to the timeline, or building a black background in Fusion. Its occurrence is random - not all black segments are affected.

Hey all, did anyone find a solution to this? I am having a similar problem to Rehan. I have random pixels appearing on top of what should just be white title cards, but only visible once the video is exported from DR. I've tried MOV & MP4, I've tried various arrangements of the clips, duplicating and rebuilding. It's happening only on my white titles, not on my footage. I've exported 6 times now and the weird pixels look different every time!
Help?!

Try reducing the render speed to see if that makes a difference.

A worthy suggestion, but changing render speed didn't help my situation.

What did, however, isn't a solution for everyone. I built a new desktop using a Ryzen 9 and a Titan RTX GPU. DRS is now running like a Ferrari with the durability of a tank.

I think I may have solved this problem, I had the same issue with black/ background pixalation.
In Deliver page(in render settings, upper left), there is an option to "Retain sub-black and super-white data" so that may be the solution.

I have had the same problem right after rendering... the pixelation does not show up on Davinci, only after rendered... I render on mp4, tried 1x speed... didn't work

Some codecs do strange things when fed full range values. Better stick to TV legal.

I had the same problem with a red-and-white picture moving across the screen (as a transition).
When I exported the video, there were pixels missing or in the wrong place.

SOLUTION for me was to export the project with 'Key Frames' set to 'Every 1 frames' (so don't use 'Automatic'). Hope this helps anyone else!

Murphy12 wrote:I had the same problem with a red-and-white picture moving across the screen (as a transition).
When I exported the video, there were pixels missing or in the wrong place.

SOLUTION for me was to export the project with 'Key Frames' set to 'Every 1 frames' (so don't use 'Automatic'). Hope this helps anyone else!

OH MY GOD, THIS IS A INCREDIBLE SOLUTION! THANKS YOU VERY MUCH

Same thing is happening for me in several spots on my video, recurring in the same places (example attached). Played with many variables including bitrate, which solved some but not all of the issues.

Setting 'Key Frames' set to 'Every 1 frames' SOLVED THE ISSUE. So thank you Murphy.

But my filesize is now 14.5GB for a ~30min 1080p video whereas before selecting this option is was 8GB.

I'm hoping there's another solution out there because I make a lot of videos and this size difference is going to add up.

It also tripled my render time.

There is no better solution. You can't eat the cake and keep it at the same time, same goes for video compression. The whole trick with small video files is NOT having every frame as a key frame.

You can try external compression with HandBrake and play with the parameters until you find your personal balance between size and quality.