400 x 222 or 720x480 ?

[deleuze3]

Hi, i have a footage of 400x222. I did my editing in Premiere, When i export it in MP4, the titles are a blurry.

When i upscale it to 720x480, the titles appear better. How come ?

Usually when you have a footage smaller than 720x480, do you tend to upscale it to 720p or 1080p ?

THANKS IN ADVANCE,
Have a good day,
Deleuze3