Updating TMH to accept VP9 input should be very easy; it sounds like the holdup is getting a compatible version of avconv on the Ubuntu 14.04 servers. :(

Producing VP9 output as well would be slightly more work, but not hugely difficult once the avconv situation is worked out.


It sounds like input is a higher priority, as fetching open-licensed videos from YouTube tends to give VP9 by default nowadays...