I just learnt of this program through an e-mail I received that makes things a lot easier, called GSpot and available from the main download section of http://www.doom9.net The program displays most of the necessary details for the AVI in one easy step, simply open the AVI file into GSpot and note down the highlighted areas shown below.

AVI filesize in bytes.
Video CODEC required.
Frame resolution in pixels.
File duration in hours/minutes/seconds