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Old September 9th, 2015, 01:27 AM   #1
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Downressed 4K comes out blurry

My 4K to 720p exports from FCP-X all come out very blurry, almost as if out of focus. I shot 1080p for a bit, but it was soft as well exporting to 720p, so I ended up staying on native 720p60.

I attached a demonstration of this. Left side is the 720p export, the right is the 4K file resized via the player box. The 4K one looks much better, even though it is squished down to a 720 size box. Anyone familiar with 4K downressing have any tips to correct this, hopefully in camera? I would increase the detail level, but not sure how "detail" subsamples all the way to a squished 720. If it involves another long process in the NLE, then looks like shooting 4K is out for this camera.

Also, FCP-X throws a warning that my computer is too slow to edit 4K. Takes only 1-2 minutes per minute of raw video to spit out 720 files, not much different than 720 raws, except I can bake an egg on my Macbook case!

Thanks!

Paul
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Old September 9th, 2015, 05:23 AM   #2
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Re: Downressed 4K comes out blurry

It doesn't look like blur to me on your stills, it looks more like heavy graining due to the camera not being able to handle tha low light, or not set up correctly. It looks like very high ISO to me and the 4k in your example doesn't really look noticeably better.

Roger
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Old September 9th, 2015, 05:54 AM   #3
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Re: Downressed 4K comes out blurry

Wow that is really full of noise isn't it ... wouldn't be worth even using that! I would try to eliminate the downsize process by shooting some 4K outdoors in bright light and THEN compare the footage.

Your downrez, especially from 3840x2160 to 1920x1080 should actually look a lot better due to chroma sub sampling!! Just a small point ..are you shooting full 4K ?? If so it doesn't have the same aspect as 1080 or 3840 UHD
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Old September 9th, 2015, 06:02 AM   #4
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Re: Downressed 4K comes out blurry

It does look better, but I have to apply a sharpening filter in FCP-X, which makes my export times quadruple. Just finished exporting 13 minutes of video, took over an hour to make it 720p60.

Yes grain looks bad, but even on bright things such as reflective license plates, they are blurred, the colors are more dull as well. 4K is about 3db less sensitive, but it has a completely different color and look. My raw 720 mode has a lot of GREEN when gained up. The 4K mode doesn't, if only it didn't take an eternity to export with sharpening. :(

Paul
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Old September 9th, 2015, 07:40 AM   #5
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Re: Downressed 4K comes out blurry

Process it through Neatvideo with a 4K intermediate (ProRes HQ) then down rez it. It will look better that way: https://www.neatvideo.com/

These are compression artifacts arising from down rezzing the 4K footage (which is only a measly 60mbps) when you convert to a lossy format like H264 for FTP delivery. If I were you, Shoot XAVC-L 50mbps 720p60 since that image holds up way better. (1080p60 if you want room to digitally zoom) Remember 4K needs 4 times as much data to compress, so 50mbps XAVC-L at 1080p60 would equal 200mbps XAVC-L at 4K60p. 4K30p only holds well at 100mbps. The X70 only uses 60mbps, which means at a 1:1 pixel evaluation, it looks worse than AVCHD. (ESPECIALLY WITH STROBING POLICE LIGHTS!)
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Old September 9th, 2015, 09:32 AM   #6
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Re: Downressed 4K comes out blurry

Unfortunatly, with my deadlines to get footage "in house" from the field, even simple sharpening is not an option. I am going to crank up the detail level to some REDONCULOUS level tonight,a nd see how it exports out to 720. I primarily want the 4K for better blacks (no green hue problem anymore!), and much much better over 12x ClearImage zoom clarity at high gain levels. Everything i shoot, EVRYTHING, airs and broadcasts at 720p60, so I could care less what it looks like in native 4K :)

Paul
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