Miro video Converter is a very simply app to convert your video files. You can convert any video that can be played on your mobile phone Android or iPhone. There are supported also these formats: MP4,WebM(vp8), Theora, Ogg etc. This software is free and open source.
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.