This summer I will be again happily involved with the Google Summer of Code inside the LibAV project. This year I have been accepted to accomplish one of the proposed tasks of the project: Rewrite avserver.
On the last three weeks I have been implementing the RTSP ANNOUNCE/RECORD. With this enhancement, the avconv can listen to an ANNOUNCE REQUEST which followed by SETUP and RECORD will allow to receive a stream and then handle the new incoming data.
The implementation is by today at my github https://github.com/nenjordi/libav/commits/rtsp-announce-preparepatch for those of you who want to take a look at its current status.