4K video editing

Complete beginner question:

I have to edit video in which I have to mix 4K and 1080 HD clips and save it as 4K.

What will happen to the 1080 HD part of it? How it will look?

Alternatively, if saved as 1080 HD how will the 4K parts look?

Or in another way to ask it - how mixed video clips (4K and 1080 HD) should be edited together?

Shouldn't be a problem to export the mixed video in 4k.  The 1080 should look a little better and the 4k rendered in 4k won't be a problem.  You can try rendering the edit both ways and see for yourself.  The exported 1080 file will be much smaller than the 4k version and will upload to Youtube a little faster.  The exported 4k file will be larger and take longer to upload, but will be a little cleaner when played back on a larger 4k monitor.

Ron Zamir wrote:

Complete beginner question:

I have to edit video in which I have to mix 4K and 1080 HD clips and save it as 4K.

Not a problem, people mix-n-match different resolutions all the time

What will happen to the 1080 HD part of it? How it will look?

Depends on the editing program and how/how well it decides to "up-rez"/process the 1080 to fit the 4k frame.  Some editing programs might have fancier algorithms that can make HD look nearly as good at 4k.  Others might just merely double up the lines/pixels.

Alternatively, if saved as 1080 HD how will the 4K parts look?

That also depends on the editing program/process.   Some editing programs might down-scale the 4k, making for super-sharp imagery, others might merely toss every other pixel, which is still ok.

Or in another way to ask it - how mixed video clips (4K and 1080 HD) should be edited together?

Well, if you know for 100% certain that you're only going to output at 1080 HD,  probably ideal to edit it all in a 1080 HD timeline, just for the sake of faster editing/processing/storage,. etc.

But most will probably recommend sticking with editing at 4k if you can, for the higher quality results in the end, particularly if down the line you want to export or share a 4k version.

As mentioned, try experimenting to see what your results and workflow are like just to see for yourself what the differences are and if you can notice the difference in the results.

Resolve has ”super scale”, similar to Topaz VE. I assume these kind of funtionality becomes more common. Photoshop does sometimes miracles by inventing content…

low_iso wrote:

Lets clear up some mythology flying around here.

1. All NLEs will scale your video for you to whatever specs you choose for your project

2. Scaling video does not improve it. Ever. There's no magic here. Up-scaling 1080p to UHD (NOT 4K!), which is 3840x2160 is an even multiple. That means within a line every 1080p pixel is faithfully reproduced, and the missing pixel inbetween is created by assigning an interpolated value, and the ineropolation is simply linear. What you get is a 3840x2160 blow up image of a 1080p image, but it isn't improved, it's just a blow-up. There's no magically creating detail that didn't exist in the original. It's still just a 1080p image, and it will look like a 1080p image, though content of the image may not show that it's really a bit softer than the 4K footage. Or it might. The exceptions might be 3rd party apps and plugins like Topaz Video Enhance, because it does SO much more than the upscaling found in NLEs. It applies several content-aware AI based processes. It also takes an eternity, and results vary a lot from flat out amazing to unusable.

3. Scaling video can degrade it. If you attempt a scaling that isn't an even multiple, like 1080p to actual 4K (4096 x 2160) you'll end up degrading the 1080p image because it won't scale evently. Much more interpolation must take place, there are no even pixel relationships at all, if you want to fill the 4K frame. Mostly when that's done it ends up just as a 2x scale and not filling the (real) 4K frame. Full up-scaling to real 4K should be avoided.

Actually,  in todays world of NLE editing apps, there IS "Magic". that magically fills in the missing pixels while retaining sharpness.

Not all NLE's do it, or do it the same.

Davinci Resolve (which is one of the most popular NLE's on this forum) has super scale, Adobe Premiere (via After Effects) has Detail Preserving Upscale. (not to mention AE natively offers different options on scaling  - BiLinear or BiCubic, the later is better for non-graphic elements)

Also keep in mind that 1080i footage needs to be de-interlaced prior to up-scaling,  in which case there is the "Preserve Edges" option in After Effects (maybe Premiere?). that also makes footage look better than just scaling it up using nearest-pixel.

and yes. all this technology does indeed improve the appearance of upscaled 1080 video, even that which has been upscaled to "true" 4k. (which honestly,  is irrelevant to the OP's question, as very few work in true-4k).

But just like with photographs that have been scaled up 200% in Photoshop, video scaled up 200% will look better.

low_iso wrote:

Gary3000 wrote:

Actually, in todays world of NLE editing apps, there IS "Magic". that magically fills in the missing pixels while retaining sharpness.

Not all NLE's do it, or do it the same.

^^^ this

But most of them do, or are capable of it.

and even without AI assistance, they fill-in the blanks, many with algorythms

Davinci Resolve (which is one of the most popular NLE's on this forum) has super scale, Adobe Premiere (via After Effects) has Detail Preserving Upscale. (not to mention AE natively offers different options on scaling - BiLinear or BiCubic, the later is better for non-graphic elements)

Perfect example of not all doing it the same. I was referring to basic scaling, not multi-algorithm or AI processes, the results of which range from spectacular to unusuable.

Basic upscaling does a fine job of upscaling, ones that use algorithms do it even better, and  AI assisted upscaling does an even better job.  is it ever "unusable?"  nah.

Also keep in mind that 1080i footage needs to be de-interlaced prior to up-scaling, in which case there is the "Preserve Edges" option in After Effects (maybe Premiere?). that also makes footage look better than just scaling it up using nearest-pixel.

Irreelevant to the OP's question, I believe. 1080i should no longer be part of anyone's discussion these days, unless they're dealing with archival footage.

99% of cameras can shoot 1080i and 1080i it's still the most dominant format being broadcast.

and yes. all this technology does indeed improve the appearance of upscaled 1080 video, even that which has been upscaled to "true" 4k. (which honestly, is irrelevant to the OP's question, as very few work in true-4k).

Um...no, not all, and not with all footage. The problem is that algorithms must make certain assumptions, and the assumptions are not always correct. Some content defys analysis. That's when manual tweaks and human judgement come it.

But just like with photographs that have been scaled up 200% in Photoshop, video scaled up 200% will look better.

Yikes, well, that's not true! Photoshop scaled images have more pixels, not more detail. The faked detail in 3rd party still or video algorithms comes from some rather intensive content prediction that fakes the detail. But, look at that detail carefully, and closely. It's not real, nor does it hold up or work well on close inspection. Great at a distance only, and very sensitive to specific content and some extremely touchy manual parameter input.

You should do a test,   open up a 1080 movie on your computer monitor and make the window 4x as big.

Then save a movie that's been upscaled it to 4k and view it at 2x as big, and view the movies side by side.

the 1080 will eventually look pixelated, while the 4k/UHD will still hold up better, because it has additional pixels and those additional pixels have additional detail that's been added by the algorithms. -even "nearest neighbor" looks better, toss in a sharpening filter (which all NLEs have), and it looks even better.