Level 1

7 points

Why is spatial conform of 4k footage so soft?

I am editing 4k (actually UHD) footage (from a GH4) on a 1080p timeline in the most recent version of FCPX. The conformed video is unexpectedly soft. I wrote a small program to do a simple quarter scaling that averaged the values of each group of 4 pixels to produce a 1920 x 1080 result from 3840 x 2160 which resulted in a much superior result. I am assuming FCPX is using a more complex algorithm like perhaps a Lanczos scaling method for rescaling, and perhaps that is better for non-integral rescaling, but in this soon to be pretty important usage, the result is very much inferior. Is there a hidden option to change the rescaling algorithm in FCPX? Does anyone know whether there is a workaround, like making a Motion FCPX effect to do the rescaling?

If not, this significantly cripples FCPX in comparison to Premiere which seems to provide the crisper downscaling of 4K that I saw also in my simple bit of code

Thanks

David Rokeby

Final Cut Pro X, OS X Mavericks (10.9.4)

Posted on Jul 31, 2014 8:10 PM

23 replies

drokeby Author

Level 1

7 points

Aug 12, 2014 7:58 AM in response to Richardttt

Thanks for this, but it is impossible to tell about sharpness of 4k to HD in a 720p movie... The issue I am talking about has to do with the fact that you can downscale 4K to HD with excellent sharpness, but in FCPX it is significantly less sharp. It is still way sharper than 720p, and comparable to most 1080p footage in terms of sharpness, but a significant notch down from 4K downscaled in Premier or by simple averaging.

David

Sep 19, 2014 5:43 AM in response to drokeby

FCPX does not do a particularly good job of downscaling 4K (or anything else). It's a pity it doesn't have an option to use a higher quality scaler. If you want to get the maximum depth out of your down-resed 4K GH4 footage, use a Lanczos transformation (or sinc for a slightly over-sharpened look, but you can't go wrong with Lanczos). Then it will really shine. I believe Motion or Compressor (on maximum settings) can do this, but I prefer to use Shake - it's legacy software but I trust it to handle things like this properly.

Sep 19, 2014 6:07 AM in response to drokeby

is it just me, or does this 'better' pic look terrible over-sharpened??

#1 is your Compressor result - just look at the small copy or at 'Mayham' - huuuge artificial white borders!

Terrible! This is not optics nor resolution, that's algorithm 'sharpness'... What were your settings in Compressor??

#2 is your FCPX export - which looks - imho! - 'natural'.

#3 is processed in Pixelmator - I have to push the Sharpen filter beyond >10% to get the same ugly result as #1 ...

...

imjigg

Level 1

4 points

Sep 13, 2016 12:41 AM in response to Karsten Schlüter

I'm having this same problem. :-( Anyone have a solution to this problem?

Emx

Level 1

18 points

Oct 10, 2016 8:50 PM in response to imjigg

I have the same problem. A 4k clip in a 1080p timeline is softer than the browser clips.

imjigg

Level 1

4 points

Oct 10, 2016 9:09 PM in response to Emx

What I've found is to work on a 4k timeline and scale up if I want to zoom in a 4k clip. I've found that FCPX does a better job at scaling up than it does at scaling down. I can go up to about 200% before I start to notice any degradation.

Emx

Level 1

18 points

Oct 11, 2016 8:06 AM in response to imjigg

My issue is working with both 1080p and 4K files on the same timeline.

I think 1080p files will lose some quality on a 4K timeline if I go that route.

I also did a test using Davinci Resolve 12 free and it does a much better job with allmost

no lost of quality with 4K files in a 1080p project.

Tom Wolsky

Level 10

152,815 points

Aug 3, 2017 5:49 AM in response to drokeby

Are you looking at the rendered output set to Hugh quality playback?

Can you post a piece of the original video that does this? Perhaps to Dropbox or WeTransfer.

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Why is spatial conform of 4k footage so soft?