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JulianGPublicInfo
JulianGPublicInfo
Known Participant
June 4, 2021
質問

Footage is blurry after downscaling from 4K despite Playback Resolution being on full

  • June 4, 2021
  • 返信数 1.
  • 6651 ビュー

Just shot an interview in 4K UHD on a Ninja V with the DNxHR HQX codec. Ingested into Premiere at that resolution and played back with no problems. However, I want to downscale to 1080p since that resolution is not necessary for delivery (just for the edit). Whenever I do though, the footage plays back and exports blurrily, despite the playback resolution being set to full.

 

The sequence is set to 1080p and I select "Set to frame size" for each clip. The renderer is set to Mercury Playback Enginge GPU Acceleration (CUDA). The crispness and clarity I want is there whenever I pause, and yet whenever I play the footage back, large swaths of the image blur (not enormously, but just enough to notice and to look off when playing back and upon export). 

 

Editing on the latest version of Premiere Pro 2021 (V15.2). 

HP Z8 G4 Workstation

Intel(R) Xeon(R) Platinum 8180

32 GB RAM

NVIDIA Quadro P6000

このトピックへの返信は締め切られました。

返信数 1

Richard TOULON
Richard TOULON
Legend
June 4, 2021

Hi,

For playback in Premiere , look what is your playback resolution in the Source and Program Monitor. By default it's 1/2 meaning that you will play half resolution.When you stop playback it gets back to full res ( you can set this up easily )

For export, it always use the full res independently of your playback settings with your monitors...so, it probably come from your exports settings.

Give us more infos with screenshots.

JulianGPublicInfo
JulianGPublicInfo作成者
Known Participant
June 4, 2021

Hi Richard,

 

Thanks for your response. Unfortunately, I've already checked playback resolution, it plainly states "Full" whether it's in playback or pause on both. Upon export, the files seem to match the discrepancy between the paused, unaffected image, vs. the played back, blurrier image.

 

I've attached photos of what they essentially look like when it's downscaled (played back in a 1080p sequence with "set to frame size" checked) vs when it is played back at full resolution in a 4K UHD sequence. There looks, to my eye, a noticeable drop in quality in both the exports and in the playbacks. In the 1080 interview image, that was exported with a bitrate of 20mbps and with Use Maximum Render Quality checked, settings which haven't facilitated such a drastic drop in quality when I've shot in 4K and exported to 1080p before (I've never downscaled to 1080p while working on a project, just edited in 4K and exported straight to 1080p depending on client needs). In the second image, the 4K one, it was exported with the YouTube 2160 settings, nothing else checked.

 

Is the drop in quality supposed to be that noticeable when downscaling? Am I approaching it incorrectly?

JulianGPublicInfo
JulianGPublicInfo作成者
Known Participant
June 8, 2021

After multiple tests ( all tests done with " Use maximum render quality" OFF )  , the only thing I can see is that from an UHD sequence, if you want to export to UHD 2160p, you should better use H265 instead of H264. The render was a little bit more crisp than H264 since this codec is made for UHD exports ( and other stuff ).

Concerning the process, it's pretty simple. If you don't know the client needs at the end ( 4k or HD for example ), always create a 4k sequence and just export in whatever format the client ask. You loose the ability to scale in the frame of course but it prevent to move or re-scale everything back if you had an HD sequence with 4K resized assets inside.

All I can say now, is make sure that your original file was crisp at 100% zoom in your timeline. If it's ok, there is no reason to have a big quality gap on your exports from the original 4k file. Have you tried to increase a little bit more the bitrate of your codec ? 

 


Hi Richard,

 

Thank you for your thorough responses, I've been troubleshooting and haven't understood how to check back with the forums (my apologies for the delay).

 

I exported to H264 in the previous images. For reference, here are two videos of clips of the interview, one in 1080p and one in 4K (once again, sorry for the delay):

https://youtu.be/V0g6f6tio4g (1080p)

https://youtu.be/VYLwEnf4rHA (4K)

 

I do know that my client wants a 1080p file at the end, plus much of the edit is going to be effects/graphics heavy, and I wanted to work with the smaller resolution to expedite render times and make it easier for my machine to work. Since I was going to be jumping back and forth between wide shots and close ups, I wanted the ability to work in 4K, which is why we shot it as such. Given that information, would an H265 export still be recommended, despite there being a 1080p deliverable?

 

I do have a 4K monitor, and once again, to my eye, the interview looks crisp in a 4K sequence. It's possible that it could be a little out of focus around the eye, that much I could concede, but it feels, given the YouTube exports, that the difference in quality between the rest of her face, the hair, and the clothes, is a bit much. Most of the time, I edit in a 4K sequence and export to 1080p depending on the situation (mostly to have a higher bitrate 4K deliverable for myself and my own purposes). I've never used a workflow in which I downscaled to 1080p ahead of the export, so my inexperience in terms of the settings could play a part. One thing that did help was checking an option in the program monitor called "High-Quality Playback," which seemed to give me a little bit more confidence in the image (though that has nothing to do with the eventual export).

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