Editing 4K Video in a 1080p Timeline, then exporting as 4K Video
I am wondering if there is a difference here. I have a mix of 1080p footage and 4K footage. Is it better to:
1. edit everything in a 1080p timeline and then when in export settings, set export to 4K (4K footage at 50% scale and 1080p footage at 100% scale)?
OR
2. edit everything in a 4K timeline and then when in export settings, set export to 4K (4K footage at 100% scale and 1080p footage at 200% scale)?
Basically what I am wondering is if Premiere Pro is smart enough to recognize the 4K footage in the 1080p timeline and not "upscale" it when exporting a 1080p timeline to 4K.