Kollege Helmchyn programmed a video editor in python: VIPER
It uses mplayer and mencoder to play and encode videoclips. this way, it reads almost every video codec and can create various outputs. The frontend is programmed in Python and TK GUI-lib. you can combine multiple videoclips in a timeline and select their length and in/out points. it plays all those clips in preview windows – very nice TK video widget!
so far the interface is not complete and there are no effects or transitions built in. if you know mencoder/mplayer options, you can put your own filters by specifying command-line parameters. i like the timeline, but there are no multiple layers and its not so easy to define the length and start/end points of the clips without seeing at which frames they will cut.
the export works very well and the dialog gives useful hints on the codecs and encoding options. It is already stable and you can use all functions of the interface.
this software is specially interesting for me, because i want a VJ player in python with mplayer, to trigger clips live on parties.. i go investigate the source code… 🙂