Level 1

4 points

What causes digital artefacts in Final Cut Pro while exporting videos?

Spent nearly a month building a website, has links to a short film I made. ( pics of sun )Exported out at 422 HQ. Odd digital artefacts visible - red vertical lines- ( in Quicktime) + on 240 mb vsn on youtube, have crept in to uploads too it seems, even visible on a new link to 3gb original on google drive (that were not seen previously?). Can anyone advise please? Website much overdue. Thanks, Mike.

[Re-Titled by Moderator]

Mac mini

Posted on May 15, 2025 4:51 AM

Top-ranking reply

joema

Level 4

1,107 points

Posted on May 20, 2025 7:42 AM

You may have out-of-gamut material which reacts differently on various monitors. In the FCP viewer, do View>Range Check>All and make whatever adjustments are necessary to avoid illegal luma or saturation levels:

Detect out-of-gamut colors in Final Cut Pro for Mac - Apple Support

As a stopgap, you can apply the built-in FCP "Broadcast Safe" filter. Increase the slider if needed until no luma or saturation zebra pattern is showing.

Then export the video in that state and test it on various monitors. This assumes you are in an SDR library and the timeline is Rec.709.

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23 replies

Mike-DS Author

Level 1

4 points

May 20, 2025 6:46 AM in response to joema

top photo is how I made the clip. its a composite slide and i couldn't 'undo' it or pick apart its elements.

Next photo the iphone camera has deeply exaggerated the issue taken from youtube oled tv, but it shows the problem, yet the photo below it shows how it does play also without showing edge problems on other screens.

May 20, 2025 7:08 AM in response to Mike-DS

I opened your youtube video, watched it in 1080p and also at the lowest option, 144p.

I cannot see these artifacts, either in the video (watching at full screen in my 1080p 24" monitor), or when scrubbing...

Have you tried this on other machines and/or displays? It may be some very specific situation that causes your display to glitch...

EDIT: sorry, I saw now in your latest post that other screens do not show the glitch

Mike-DS Author

Level 1

4 points

May 20, 2025 8:54 AM in response to Ian R. Brown

Thanks for that positive response Ian. There is a problem of some sort there, it seems to show differently on different monitors, and I've seen it look appalling and am loath to add it as a link (to project I've spent 18 months on with all the music I've done) within a 30 minute film - I'm sending out clips soon..... one person here has suggested 'out of gamut colours' and a 'broadcast safe' filter. I've a hunch these are in the right area, and will investigate further if I can make the right adjustments. It's good to know it looked fine on your monitor!

Thanks, Mike.

Mike-DS Author

Level 1

4 points

May 16, 2025 3:46 AM in response to Luis Sequeira1

Thanks Louis. I will see what I can do today. Many thanks. Mike

Mike-DS Author

Level 1

4 points

May 19, 2025 4:21 AM in response to Luis Sequeira1

Hi Louis - so how can I share a Source clip - its several overlaid using masking.

Thanks

Mike

Mike-DS Author

Level 1

4 points

May 19, 2025 11:43 AM in response to joema

Thanks very much. Will send info tomorrow ( am in U.K.)

thanks again

mike

May 20, 2025 8:32 AM in response to Mike-DS

It looks perfectly OK on my 27" 4K Philips monitor.

May 21, 2025 12:01 AM in response to Mike-DS

Where in the UK is broadband so slow that it will take over 9 hours to upload a clip? Outer Hebrides? 🧐

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What causes digital artefacts in Final Cut Pro while exporting videos?