4K files, but FullHD editing and export

Hello!

Iam just about to start to edit a project I have shot in 4K, but I already know that the final video file will be in Full HD.

If I remember correctly I don't have to transcode all my files from 4K to 1920x1080 to start editing first.
Since I just set my timeline settings to HD.

Would be great if someone could confirm me this. Or let me know if there are some general concerns and common mistakes.

Greetings from Berlin!

Henning

if you transcode it to a smaller file before editing, it will become easier to handle for your computer (if transcoded correctly) so thats a big plus. i mostly did that too, but since i have a new setup im editing more and more in 4k/5K, even when the final video will be ''just'' HD. i just export the final result to HD. though i still notice a big difference in performance while editing.

it really depends on what kind of project it is. for example when im editing with alot of multicams, transcoding to smaller files really boosts the workflow since its just easier to handle.

With a fast enough computer, it's not necessary to transcode first. You can also elect to use Optimized Media to do this automatically.

Just make sure you change the timeline to 4K (or whetever the files' native resolution is) prior to the render, to make sure you're scaling from the maximum resolution. This doesn't make a difference all the time, but it will make a difference in blow-ups and repo's.

Just make sure you change the timeline to 4K prior to the render, to make sure you're scaling from the maximum resolution. This doesn't make a difference all the time, but it will make a difference in blow-ups and repo's.

Say what now?

I am still new to Resolve, but that seems...wrong.

If you're editing UHD media in a 1080 sequence, you'll have to scale down the clips to 50% to see the entire image. Which is fine. Scaling down is no problem.

That means you can go up to 100% for a punch-in/reframe without actually scaling the image at all, thus keeping all the original quality.

But if you change the sequence to 4K before export, those punch-ins will be scaled up to 200%. Scaling up is bad. That's what loses quality (beyond a certain point).

No?

Just make sure you change the timeline to 4K prior to the render, to make sure you're scaling from the maximum resolution. This doesn't make a difference all the time, but it will make a difference in blow-ups and repo's.

Say what now?

I am still new to Resolve, but that seems...wrong.

If you're editing UHD media in a 1080 sequence, you'll have to scale down the clips to 50% to see the entire image. Which is fine. Scaling down is no problem.

That means you can go up to 100% for a punch-in/reframe without actually scaling the image at all, thus keeping all the original quality.

But if you change the sequence to 4K before export, those punch-ins will be scaled up to 200%. Scaling up is bad. That's what loses quality (beyond a certain point).

No?

Yes. You are correct. For a HD 1080 timeline output to HD 1080, no further output scaling is necessary or desirable.

Say what now?

I am still new to Resolve, but that seems...wrong.

If you're editing UHD media in a 1080 sequence, you'll have to scale down the clips to 50% to see the entire image. Which is fine. Scaling down is no problem.

That means you can go up to 100% for a punch-in/reframe without actually scaling the image at all, thus keeping all the original quality.

But if you change the sequence to 4K before export, those punch-ins will be scaled up to 200%. Scaling up is bad. That's what loses quality (beyond a certain point).

No?

Hey Jim.

its all in how Scaling is set, either individually in clip inspector, or in Settings.

The default Scale entire image to fit will treat your UHD source in an HD timeline as HD. So new 100% to clips instead of 50%.

You need to change it to Center crop with no resizing if you want source to be treated at its original resolution and scaled accordingly.

To stick to the OP, if 4k won't ever be required at any moment (including just a single export for whatever reason), I'd still transcode to a good profiled ProRes or equivalent... Doing it by the "optimize media" way or real transcode doens't really matters, but in the end the project would be smoothened for sure.

The default Scale entire image to fit will treat your UHD source in an HD timeline as HD. So new 100% to clips instead of 50%.

That's good to know. And...unfortunate.

Here some tests :

(allways output scalling => Mismatched Resolution files : Scale entire image fit. Test are only for a delivery 1080p with my system)


Clip UHD @50fps
TL resolution 1080p
Monitoring HD 1080p 50 (full monitor)
Input Scalling : Scale Entire image to Fit
Output Scalling/resolution: Match TL setting => ON
delivery is 1080p full image
Playback : 50fps / CPU 45%


Clip UHD @50fps
TL resolution UHD 50p
Monitoring HD 1080p 50 (full monitor)
Input Scalling : Center crop with no resize
Output Scalling/resolution: HD => ON
delivery is 1080p full image
Playback : 50fps / CPU 45%


Clip UHD @50fps
TL resolution UHD 50p
Monitoring UHD 50p (crop by 4 monitor)
Input Scalling : Center crop with no resize
Output Scalling/resolution: HD => ON
delivery is 1080p full image
Playback : 16fps / CPU 29%


Clip UHD @50fps
TL resolution UHD 50p
Monitoring UHD 50p (crop by 4 monitor)
Input Scalling : Scale Entire image to Fit
Output Scalling/resolution: HD => ON
delivery is 1080p full image
Playback : 16fps / CPU 29%


The best is (if you are sure to keep fullHD in delivery) :

Clip UHD @50fps
TL resolution 1080p
Monitoring HD 1080p 50 (full monitor)
Input Scalling : Scale Entire image to Fit
Output Scalling/resolution: Match TL setting => ON
delivery is 1080p full image
Playback : 50fps / CPU 45%


and for a small benchmark:

Clip UHD @50fps
TL resolution 1080p
Monitoring HD 1080p 50 (full monitor)
change playback Frame Rate to 100
Input Scalling : Scale Entire image to Fit
Output Scalling/resolution: Match TL setting => ON
delivery is 1080p full image
Playback : 77fps / CPU 96%

clip IS from Sony FS7 :

Code: Select all

Format                                   : MXF
Format version                           : 1.3
Format profile                           : OP-1a
Format settings                          : Closed / Complete
File size                                : 381 MiB
Duration                                 : 6 s 520 ms
Overall bit rate                         : 491 Mb/s
Encoded date                             : 2017-09-30 05:07:56.000
Writing application                      : Sony util 1.00

Video
ID                                       : 2
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High 4:2:2 Intra@L5.2
Format settings, CABAC                   : No
Format settings, GOP                     : N=1
Format settings, wrapping mode           : Frame
Codec ID                                 : 0D01030102106001-0401020201323001
Duration                                 : 6 s 520 ms
Bit rate                                 : 481 Mb/s
Maximum bit rate                         : 500 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 50.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:2
Bit depth                                : 10 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 1.161
Stream size                              : 374 MiB (98%)
Transfer characteristics                 : BT.709