Changing the Video Stream Size ? ? ?

[Brand-New]

I’m trying to append one AVI file to another. Both files originated from the same source; but when I attempt to append the second file to the original file, an error message complains that the video streams are different sizes, and will not allow me to proceed. As a Brand-New novice, my reaction was to modify the size of the video stream.

Is modifying the video stream size the way to go? If so, how should I do that? If not, what is a more workable and appropriate solution? (Please specify the all steps I need to take.)

Thanks a 1,000,000

[MilesAhead]

Get MediaInfo
load the videos into it and post a screen shot.