ffmpegX problem

[air]

please help
when I try to encode a .mov file to .avi file in ffmpegX it sais:
Output video width is not divisible by 16.

where I can define that width value please?

what should I do?

[Case]

In the upper half of the window is a bar with six tabs: Summary, Video, Audio, Filters, Options, Tools.
Click the Video tab. The window changes to show video parameters, specifically on the right side. The Video Size fields show the width and height of the output. Change the width to the closest multiple of 16. E.g. if the value was 622, change it to 624.