HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded
DVD to MPEG-4 converter, available for MacOS X, Linux, Windows and
FreeBSD.

Supported sources:

    * Any DVD-like source: VIDEO_TS folder, DVD image or real DVD
      (encrypted or unencrypted, but protection methods other than CSS
      are not supported and must be handled externally with third-party
      software), and some .VOB and .TS files
    * PAL or NTSC
    * AC-3, DTS, LPCM or MPEG audio tracks

Outputs:

    * File format: MP4, MKV, AVI or OGM
    * Video: MPEG-4 or H.264 (1 or 2 passes or constant quantizer/rate
      encoding)
    * Audio: AAC, MP3, Vorbis or AC-3 pass-through (supports encoding
      of several audio tracks)

Misc features:

    * Chapter selection
    * Basic subtitle support (burned into the picture)
    * Integrated bitrate calculator
    * Picture deinterlacing, cropping and scaling
    * Grayscale encoding

WWW: http://handbrake.m0k.org/