Recommending an easy way to add logo or text to videos without command line is to download a watermarker like Bigasoft Total Video Converter. I used it and it can add watermark to AVI, Xvid, DivX, H.264, MP4, 3GP, MKV, WMV, RM, FLV, MOV, WTV, MXF, MVI, F4V and so on.