Open source video converter HandBrake and others.
Formally known as MediaFork, Handbrake is an open source, GPL- licensed, multi platform DVD to MPEG-4 converter. The most recent version, released 8 October, 2007 came out with many additional features. HandBrake 0.9.1 takes your DVDs and video sources like VIDEO_TS folder, DVD image , PAL or NTSC, AC-3 or MPEG audio tracks and and gives them back to you in major file formats like MP4, AVI, OGM and video formats like: the pro iPod MPEG-4 or H.264 and audio formats like : AAC, MP3, Vorbis or AC-3. Its worth mentioning that the ripped files can be played by Zunes and many other devices.
For Linux platforms, this final release is available for download as source code.
Two free Web Applications that serve as efficient video encoders are Hey!Watch and VidDownloader
Hey!Watch converts video uploaded from your desktop as well video on sites into wide variety of formats like H264, MP4, WMV, DivX, HD Video, Mobile 3GP/MP4, iPod, Archos and PSP. Above 10MB of upload per month, the service becomes commercial.
VidDownloader could be used to make a save and personal copy of video found around the web. It picks-up video from streaming sites like YouTube, Google Video, Yahoo etc and converts them to playable video formats and it gives it back for download in the popular AVI format, thus compatible with DivX.