I am trying to wtrite s a script that will either give mplayer an option to crop an automatic amount determined by if the movie is 4:3, 16:9, or 2.34:1 . Here is wher i am getting confused.

The following data was collected either by mplayer, or avitype. They both got the same (heightxwidth) data:

here is the dimensions and aspect ratio I get when playing a full screen movie
608x448 for a aspect ratio of 1.36

here is the dimensions and aspect ratio I get when playing a widescreen movie, not the "very thin", but the "moderate" widescreen.
688x368 for an aspect ratio of 1.87

here is another of the same type(moderate) of widescreen
672x368 for an aspect ratio of 1.82

This is where nothing is making sence. When I play a very thin wide screen, what I thought has an aspect ratio of 2.35:1 it is not giving me that data according to avitype or mplayer. When I measure my moniter I am getting an aspect ratio closer to 2.4:1, this is in proper proportion. But mplayer or avitype give me these numbers
650x366 for a ratio of 1.78 , but the movie is playing with a ratio of 2.4:1 . All of my 2.35:1 widescreen movies say the aspect rario is 1.78(according to avitype, or mplayer) , but it is in actualliyty closer to 2.35:1

why are my 2.35:1 widescreen movies behaving this way.

I take it you're using .avi files which were ripped from DVDs?

The DVD format supports only one widescreen aspect ratio--16:9, or 1.78. The dimensions of the actual video are 720x480, with squashed pixels. The movie itself usually has an aspect ratio of 1.85 or 2.35, with black bars at the top and bottom to fill it out to the standard DVD aspect ratio of 16:9.

(Don't ask me why DVD widescreen aspect ratio is 16:9 when no movies are made in that exact ratio.)

When someone rips DVD video to an .avi file, it's usually rescaled to something with square pixels but retaining the original 16:9 aspect ratio. 640x360 is convenient, but really any dimensions could be chosen, arbitrarily.