Avidemux is a very powerful tool for editing video files. It supports almost every type of video file as input. It can do lots of things: cut, remux, convert, etc. It contains its own decoders and encoders for all common audio and video formats, so it does not need any external codecs.
ImgBurn is a versatile tool for burning DVDs.
DVDStyler is a basic DVD authoring tool. With this you can create your own video DVD, complete with a custom menu.
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