Pixel Aspect Ratio and ciphering type of footage-CS6

CS6- updated 12\18\13  V-11.03

Hi All,

A few questions about:

Pixel Aspect Ratio and ciphering type of footage. Bare with me as I touch on two different aspects of what I feel are related:

1. Setting up a Comp-

Having AE decide on the correct footage being used- Via >Import footage,.(to Folder) then drag it on, or into the 'make comp icon' where AE is supposed to do a 'best guess' for the comp settings. Be it square pix or otherwise. What are the second value in brackets ? See pic

2. Interpolation-

When using two diff footage sources- If using two different source footages in a comp. Is this where I should interplolate my footage to match the existing footage and the comp settings (If I have choosen NOT to pre-comp that secondary footage?)

3. Seperating fields-

How come footage that a camera manufacturer claims to be shooting in Progressive 30 or 24p is showing up as interlaced in my comp's CP? The manual to the cam says 30p or 24p or 60i The footage was shot at 30p (for sure)

Here is a screen grab of AE's 'best guess' of that footage, showing it with an UPPER field render; indicative of HD Interlaced footage and then in the inerpolate settings - 'kinda confirming it.

Now for the way out- Render:

4. If that is in fact Interlaced and I then want to reduce the size of that 1920 footage to 66% size... Do I need to do anything in particular at this point?

For some reason I am getting an error on my end when trying to export as an AVI and reducing size to 1280

5. Is this from the Field render of interlaced challenge?

I ended  up with a couple of errors and then aborted the whole file and re-imported to start over with this error. Which happend again after a redoux

So I sent it over to Prem Pro to export those MTS Files as a movie and noted AGAIN the reference to Interlaced video. "upper and lower" Prem Pro was able to use the same MTS files and export a working movie. (so those files were not corrupt BTW) Yet Note PP's output reference to that footage again as Interlaced would be...

Thanks for any clarity on those "5" questions... NC