VLC

It began as a student project at École Centrale Paris in 1996 to stream video across the campus network — VLC stands for VideoLAN Client. Released freely in 2001 under the GPL. It carries its own decoders (much of it via libavcodec) rather than relying on the system's.

It can also stream, transcode, play back damaged files and nudge audio sync. Run by the non-profit VideoLAN association, it has never shown an advert. The traffic cone comes from a collection the student society liberated from the streets of Paris.