1 - C/Cpp, Python. Knowledge in other languages is a plus! ( exept php :) )
3 - Front-end stuff - QT, HTML5 & co. Know how on working with these in multimedia applications is a big plus!
4 - Tools like FFMpeg, Transcode, Mencoder & various AV codecs, containers, muxers, streaming,...etc
If you feel you are good with the above, please feel free to reachout off-list.
If you are not well versed in the last requirement (#4) but are confident you can learn quickly, still feel free to reach out & let me know.
Cheers!