Here is a nice software for video thumbnail and supports of practically any videos-formats. Is called Video Thumbnails Maker and allows you to make thumbnails (caps, previews) of video files. The utility can be used for home-video cataloging and for network video sharing support.
Video Thumbnails Maker is small size program with customizable fonts, colors , contours, shadows, frames, background etc. Available in 5 different languages and very simply to use.