I've been researching this one for quite a bit but haven't found any solid leads.

I have a Wowza/Flash app with video chatroom functionality and would like to combine the streams server-side into one video/audio stream in order to be sent to a live Youtube channel.

I've found a couple projects such as jMixer and some helpful keywords such as "vision mixer" to help with my search but looking for any previous experience or new ideas.

The other option is building something like it myself with a commercial video decoding/encoding library to raw frames, stitching the frames together, then encoding it. I was originally going down this route but put project on hold.

What are some ideas, keywords, or existing software (open source preferred) to take those live streams and combine them into one in real-time? Or is coding it myself the required route?

Thanks!