It appears to me as SD quality (subjective feeling). YouTube runs 4k videos even on my
Sony full HD
tv and displays 4k only in settings. So I am sure sure it either compresses or runs lower resolutions in boxes or TVs it can't run 4k. So not sure if we are really running 4k even in TVs which support 4k . If you check Jiofibre set top box detailed specs in Droid info it displays 1080p only on my
Marq Android TV which is 4k. I will check stats for nerds tommorow and post again