Export for differents camera resolutions.

[lkmlkmln68567018]

Hi Adobe community, 

I have one question. During a shooting vidéo i have filmed with  différents caméra. Some in full HD and some in 4K. So my question is on the export. I would like to know if there is a solution for uniform the video quality of the editing during the export. (optimise the transitions between videos)

Thanks in advance for your help ! 

Best

[R Neil Haugen]

Full HD is normally 1920x1080, while most "4k" is actually only UHD ... 3840x2160. Full 4K is 4096x2160.

As scaling up is always problematical, when mixing HD/UHD media, the normal practice is to work on a 1080 sequence, with the scaling option in Preferences set for "set to frame size" so Premiere automatically sets the UHD media to show on the HD sequence. Yet doesn't scale the clip internally, so you can re-size the image (zoom) as you like without problems.

Neil

[lkmlkmln68567018]

Thanks for your fast reply,

Of course, that's have done. But the the probleme is that for some 4k vidéo i doesn't resize enough (because my composition doesn't ask more resize)  for uniform the editing. For this raison we see a différence of "sharpness".

[R Neil Haugen]

Putting 4k or UHD media on a 1080 sequence should not present any issues with sharpness. Putting 1080 on a 4k/UHD sequence would.

With the preferences option set at "set to frame-size" you can re-size/scale without troubles, as you are still using the full pixel data of the original media to create whatever scaling you ask for. It will initially place the media on the sequence at the size that completely covers the image of the sequence frame-size with the image of the clip.

And if you then say zoom in more or less, it still recalculates from the original pixel data, not the pixels used for the 1080 view of the image.

However ... if the preferences is set to "scale to frame-size" ... then Premiere recalculates the image pixels to that frame-size. This means, with a 1080 sequence, that Premiere takes a say 3840x2160 pixel image and re-scales that down to 1920x1080 pixels as the new image. And if you then up-scale, it upscales from the 1080 image, not the original file data.

So in that case, with 'scale to frame-size' used, you would have sharpness/resolution issues on upscaling/resizing the images. Because you've used the wrong method to place on the sequence.

Neil

[salvo34]

Normally when multiple cameras are used for a scene they are the same type cameras. If they are different ( for stunts and special effects ) they have similar settings as much as possible. Usually the specialty camera(s) will only give a second or less of 'footage' for the scene, so it's very fast and audience sees the effect ( slo mo etc. ) more than they notice difference in Quality or Sharpness.

4K (DCI) is for movie theatre projection and is wider than 16:9 ... which is what UHD and 1080p is.

So, if shooting that as your 4k then you'll scale it up to get rid of letterbox in a 1080p timeline.

Between that upscale and the different lenses on cameras ( lenses have a lot to do with sharpness ) you may see some differences between the two cameras you have used.