Crappy CGI?

Now the first thing that must be said about this 2nd hit footage is that it has a truly miraculous zoom: the camera operator rapidly zooms out and stops his zoom JUST IN TIME to catch the "plane" coming in. Really, people had the most AMAZING LUCK with their cameras on 9/11.

But more relevant to this post, note how crappy the "plane" image is here. The question is-- if someone is going to go through the trouble of adding a CGI "plane" to a 2nd hit video-- why make it so crappy?

This thing is clearly missing one wing and a tail section -- this is not a simple matter of resolution-- and it is too short for a Boeing 767 (roughly 137 feet as opposed to 159-- so about 14% too short).

Was this the real object that hit the tower whose appearance was "fixed up" in other 2nd hit videos? Or a CGI plane-like image designed to look bogus?

What is most confusing is the planes in the "live" videos (e.g. #1 here)-- if they were CGI, they were clearly better quality, but how could they cover-up a real object with CGI so quickly in real-time? But if the planes in the "live" videos were real, how come they have normal starboard wings and tail sections? Although for whatever reason, the live planes ALSO seem too short for a Boeing 767.