MPEG Streamclip is one of the most COMPLETE and FREE media encoder of the market. You can use it especially to encode your video in .mp4 format with H.264 codec. It works both on a Mac and on PC. Here is a quick demonstration on how to encode a video in .mp4

Anyone who has been trying to view some videos knows probably the VLC video player. In our case, we are going to use the ability of VLC to encode any kind of video file into a ogg video file. Here is a quick demonstration on how to encode a video in .ogg with the VLC

A great tool for a great browser. If you are using HTML5 and firefox as a browser, you may have heard of this Addon that enable to encode any kind of video onto .ogg format. Without any desktop app to do the conversion, Firefogg will help you in creating an ogg file.