4K rendering to 1080p

Maybe a silly question but :

Say, I shoot all my clips in 4K - HEVC with my iPhone 7 to capture the most out of my camera…

But my tv (older on) only plays 1080p.
So anyway, if I want to play my edited videos on my tv, I must render in HD (1080p).
But what if I import all 4K clips on a 4K timeline, make all my edits and then finally render it all to 1080p…

Would that give me more quality output or not…?

That’s my question.

Thanks for your replies.

There are several options:

  1. 4K footage, 4K timeline, 4K export. Then connect a computer to the TV and use a media player for your videos. The media player will downscale 4K to 1080p to accommodate the TV. When you later upgrade to a 4K TV, your footage will be 4K ready to go. This would be my personal vote.

  2. 4K footage, 4K timeline, 1080p export using bicubic or Lanczos interpolation. This will create a fantastic 1080p. Since the source material has 4x the data as the final export, there will be fewer artefacts such as edge roll when doing rotation, or pixelation when zooming in. Averaging four pixels into one for export also has the nice side effects of averaging out some ISO noise and achieving smoother, more accurate-looking colors. This is the second best option.

  3. 1080p footage, 1080p timeline, 1080p export. The least inspiring option. There is a highly noticeable difference between 4K -> 1080p versus 1080p -> 1080p. All image capture techniques have problems, such as inaccurate colors, photon shot noise, dark current, ISO noise, and so on. When the whole chain is 1080p, those sample errors are exaggerated when filters are added (such as size stretching or color grading). But if the source is 4K (more generically, if the input has 4x more data than the output), then per-pixel sample errors can be averaged closer to the true colors when downscaled for final export, and the result looks much better.


Thank you so much for all these advices.
Well explained and appreciated.
I will try both first and second options soon.

Could you please be more precise about lanczos and bicubic…?
Is that something inside Shotcut…?

Yes, it is a drop-down box on the Export > Advanced > Video tab. I am mobile and can’t take a screenshot at the moment.

Lanczos will create a sharper image than bicubic. For average footage, this is a good thing. But if the source footage came from a computer rendering or has lots of harsh lines and geometric shapes and such, then Lanczos can sometimes create ringing or halo artefacts. Bicubic is a little softer on the edges and will avoid problems in those scenarios.

Thanks, I thrilled to test these settings.

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