when resizing your video youve got two options: cropping the original video (and resizing as appropriate - in this case, h10 5g screen size is 128x128px) OR stretching your original video vertically - so its height is the same as its width - then resizing as appropriate (again, h10 5g is 128x128px). see attached pic for mspaint-y explanation
(extra: mspaint in wine!)
edit: sorry i cant recommend a program to resize your video. there are hundreds and the majority are crap
