mp4 or avi

[cootmaster]

i used to convert EVERYTHING with different extensions
because my dvd players played AVI XVID One played MPG1 and one played VCD.
but now , 700 meg discs are ridiculously small , i haven't burned anything since 2012.
now keeping EVERYTHING on external drives one which i took down which was only 140 gigs and moving it to a 256 gig jump
and soon to my internal terabyte when i dump windows 7.
so i just use chromecast to watch EVERYTHING on my tv.

i was wondering, now im not burning anymore
which is the BEST format to convert to , with best picture and sound .
one my downloaders uget has AVI where 5kplayer has mpg4 as default
but by editor the editor i use is avi
i noticed a few videos in mp4 where somewhere between 7 and 10 megs , AVI XVID were a whopping 15 to 18 megs !!
is going MP4 a better extension when i get rid of w7? and format it for storage?

[stevo]

Yes, mp4 is a container that can use more advanced codecs than AVI, like h.264 (the defacto standard now) or even better ones like h.265, vp9, or even the extremely-slow-encoding-now-but-may-get-better-in-the-future AV1. You might want to try Handbrake for encoding to newer formats.