I'd like to build some kind of display appliance that plays videos and displays some text. I'm thinking of a diskless system running a Knoppix derivative loaded into RAM. There will be a few scripts in the background that handle the scheduling of displays. For showing video clips I'm thinking of mplayer in full screen mode.

But right now I don't have anything for the text overlays. Here are the requirements:

• mode 1: reads text file and displays text line by line, more or less like subtitles in a movie
• mode 2: scrolls the text like on some of the news channels on TV
• Unicode compatible, in particular traditional Chinese
• background transparent, the mplayer should show through, not the root window. Configurable alpha settings are optional.
• foreground (text color) not transparent, color configurable
• fonts configurable
• refresh rates, scroll speed configurable
• smooth scrolling (not character by character as in the 'ticker' app that's available in the Debian & Ubuntu distros)
• always on top, no matter whether this app or the mplayer was started first
• preferably open source

Does anyone know whether such a thing exists anywhere? If not, and if I'd have to build my own (in Perl or Python), which widget set and windows manager would you recommend?

That is a lot of requirements.

The only thing I have seen come close is the Pygame programming environment (http://www.pygame.org). You can move things around, scroll text, use transparency and truetype fonts. As the name suggests you write your application in python.

It also has facilities for playing movie clips (MPEG format) but I never tried that out, so I don't know if you can overlay text.

Pygame is built on top of SDL multimedia library (http://www.libsdl.org/). MPlayer can output to SDL, so you may be able to incorporate other video formats somehow, or use SDL directly. Never been there, so can't offer much advice.