
It's a program totally free video converter, which supports an incredible amount of audio and video formats, and can convert between them with ease: 3GP/3G2 (Nokia, Siemens, Sony, Ericsson) asf, avi (DivX, H263, H263+, H264, XviD, MPEG4), dat, fli, flc, flv (used in Flash), mkv, mpg (Mpeg I, Mpeg II), mov (H263, H263+, H264, MPEG4), mp4 (H263, H263+, H264, MPEG4), ogg, qt, rm, ram, rmvb, str (Play Station), swf (Flash), ts (HDTV), viv, vob, wmv. Similarly, many audio formats are supported (ac3, amr, mp2, mp3, mp4, mpc, ogg, ra, wav, wma).
It can also convert between avi video, for example, but created with different codecs (for example, created a video with H.264 and AAC can be converted into a normal divx with mp3 audio, executable in any reader board, or vice versa).
The graphical interface has been that a few years ago, and is not the best (to say the least).
Super was the first program to allow free conversion video/audio between many formats. Today is a good program (especially because it still supports many formats), but suffers a little bit of competition, mainly because of the graphical interface which, as mentioned, is not the best.
Sometimes there can be problems after the conversion, synchronization between audio and video (especially if you convert a 720p or 1080p MKV to AVI), but I have not encountered problems with Xvid4PSP.
NOTE: The download link is a bit hidden around the site, you need to look carefully.
Unfortunately, though years ago it was the best program category, has recently lost several points.
Super