color grading 4k footage in 4k timeline or 1080p?

A

Alan Ting Judson

Well-known member
Will receive my 7Q+ this/next week for my a7s. Just want to confirm which one is better for editing 4k video.

I would like to export in 1080p at final. So which method is the best for color grading the footage?
1. Just put the 4k footage onto 1080p timeline > colour grading > export in 1080p
2. After convert the 4k footage to 1080p > put the converted footage into 1080p timeline> colour grading > export in 1080p

Cause heard before we can get 10bit luma info when downscaling to 1080p from 4k, so wonder if the 2nd method will be easier and better for colour grade than the 1st method? or both give same result?
 
I found that my PC was unable to handle 4K DPX files in real time, so I ended up creating a 1080P DNxHD proxy, and swapping the media for final render. Source material was an 8-bpc GH4 4:2:0

I was eventually outputting going to 4K, but if you are staying 1080P, as long as you down sample properly to a 4:2:2 10-bpc codec you might as well stay there to save on disk space and performance.
 
If your computer is fast enough, method 1 is the most efficient. You won't see any significant quality difference with either method.
 
Alan Ting Judson said:
Cause heard before we can get 10bit luma info when downscaling to 1080p from 4k, so wonder if the 2nd method will be easier and better for colour grade than the 1st method? or both give same result?
Click to expand...

No that is not the case. You get pixel averaging/smearing that happens when you downscale so you get tonal values that are averaged with the pixels that are combined. it is not true 10 bit colour by any stretch. Does it look better than 8 bit and will it grade better? Depends on who you talk to. Most will say it looks a bit better and 1080 downscaled from UHD seems to appear to resolve the details better. You will see examples online if you google.
 
Method 1 is better, but your computer may not be up to the task. Method 2 will give you better performance but requires an initial transcode (which means both time and a minor quality hit, unless you transcode into lossless 10-bit 444, which I would't do).
 
Alan what hardware and software are you using for all of this? my 2 year old i7 with gtx 670 and 16gb ram is plenty to deal with editing/grading 4k prores footage. i edit in premiere then color in speedgrade (so maybe davinci would be different) seems a lot more efficient than converting it all to 1080 first. applying effects like denoising can be really intense at 4k though, so if you plan on doing a lot of that and mastering at 1080 anyways.... that'd be the only reason i could see it being worth it.
 
Indeed, MB Denoiser II slows to a crawl with 4K footage. Like: if you haven't tried it, you have no idea. Much slower than you still think.
OTOH, if you're shooting 4K in order to reframe in post, then you probably want to work with the original 4K files.
 
Thanks for all the feedback. So conclusion will be method 1, edit 4k at 1080p timeline straight away. I had few macbook pro for editing, 2014 and 2012 version with highest spec. My 2012 macbook prostill ok to handle 4k, customise my internal hard drive and disk drive change to RAID 0 SSD, help a lot in speed.
 
If your computer can handle it I would edit 4k on a 4k timeline and then down scale at the end. I always edit at the highest captured resolution and then export to what ever resolution at the end. It is very easy to down scale at export but not nearly as easy to update the entire project if you later decide you want to output to 4k...
 
In FCPX I edit UHD footage in a 1080 project, it is very fast and efficient. Rendering titles or effects are much faster than a UHD (or 4K) timeline.

Then when it is all done and I need to output UHD, I just change the Projet to UHD. Then "share" it whatever way you need to like Vimeo 4K, or as a "Master file".

This way there is no loss at all and work is fast.
 
olof said:
In FCPX I edit UHD footage in a 1080 project, it is very fast and efficient. Rendering titles or effects are much faster than a UHD (or 4K) timeline.

Then when it is all done and I need to output UHD, I just change the Projet to UHD. Then "share" it whatever way you need to like Vimeo 4K, or as a "Master file".

This way there is no loss at all and work is fast.
Click to expand...

I haven't edited much in 4k (just GH4 footage), so there's no difference in the way the end product looks compared to starting with a 4k project? If not this is really clever. Thanks for the heads up.
 
photochris said:
I haven't edited much in 4k (just GH4 footage), so there's no difference in the way the end product looks compared to starting with a 4k project? If not this is really clever. Thanks for the heads up.
Click to expand...

There is absolutely no difference in the final result. It works great, it how I always work on UHD footage now. And a lot of times all you need is 1080 with some zoned or smoothed footage, then this is great as well for delivering in HD. Big time saver and renders go much faster.

The only downside is if you are monitoring on a 4K monitor, then you will notice the difference. I currently just use 1080 SDI pro monitors for editing, as well as a consumer 1080, just to see how bad consumer monitors really are. Soon I plan to get a 4K consumer monitor and use BM 4K express to view in UHD, then I will probably still use 1080 for most of the editing. You can just copy and paste parts into a 4K timeline and if the original files are 4K then they will play as 4K in the 4K timeline, so you can check critical shots this way to make sure you nailed focus etc.
 
olof said:
In FCPX I edit UHD footage in a 1080 project, it is very fast and efficient. Rendering titles or effects are much faster than a UHD (or 4K) timeline.

Then when it is all done and I need to output UHD, I just change the Projet to UHD. Then "share" it whatever way you need to like Vimeo 4K, or as a "Master file".

This way there is no loss at all and work is fast.
Click to expand...

That is fine if is just a simple edit, but if you use any masking, windows, tracking, stabilization... that may not be the case anymore.
 
olof said:
In FCPX I edit UHD footage in a 1080 project, it is very fast and efficient. Rendering titles or effects are much faster than a UHD (or 4K) timeline.

Then when it is all done and I need to output UHD, I just change the Projet to UHD. Then "share" it whatever way you need to like Vimeo 4K, or as a "Master file".

This way there is no loss at all and work is fast.
Click to expand...

seem like a great tips! thanks!
 
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