If you are looking for a simple way to convert DVD files, as well as DV and DVB videos into a compressed format, StaxRip is what you are looking for.
It's a free and open source application that lets you convert any video in the formats mentioned above into a compressed video format file.
StaxRip supports video files in DivX, XviD, x264, MPEG-2, and MPEG-4; and audio files in MP3, AC3, MP2/MPA, AAC, DTS, and WAV.
You just have to choose the file you want to convert and the resulting format. You can also adjust some parameters to modify the resulting file settings and size. In a relatively short amount of time, depending on the original file's size, you can be enjoying an excellent video quality file, with a much smaller size.
