Audio Level Delivery in the SIP Express Media Server (SEMS)
GSoC Student: Mihaita-Alexandru Leoveanu - (Romania)
Mentors: Stefan Sayer (Germany), Raphael Coeffic (France/Germay)
Project Requirements ( )
First term:
- Item 1
- Item 2
Second term:
- Item 1
- Item 2
Since recently SIP Communicator is able to send, receive and display to users the audio level of every participant in a conference call. The feature is pretty useful as it allows you to easily identify speakers or sources of noise (e.g. the guy who pushed the mike under his nose and whose breathing is now preventing you from hearing anything at all :) )
Well, the folks from the SEMS project agree with us on how handy these levels are and would like to have them too. You may be wondering why a media server such as SEMS would need to care about something that is clearly a User Interface concern. Well, the reason is that when you participate in a conference call audio data from all participants is mixed in a single stream before it is sent to you. It is therefore almost impossible for your client to determine the audio levels of the other participants by itself.
You can find more details about how all this works in these slides and the rest of the references in the bottom of this page.
This project is therefore about adding the following list to SEMS:
- Support for audio level analysis in SEMS that would allow determining the level of audio streams
- Support for the RTP header extensions that are necessary to send the information to the other participants
- Support for SDP negotiation of the above.
This project will be mentored by members of the SEMS development team.
References:
SIP Express Media Server
http://www.iptel.org/sems
Support for audio levels in SIP Communicator
http://sip-communicator.org/gsoc2010/SIP.Communicator@FOSDEM-2010-02-06-updated.pdf
The audio levels RTP extension
http://tools.ietf.org/html/draft-ivov-avt-slic
A SIP Event Package for Conference State
http://tools.ietf.org/html/rfc4575
A Framework for Conferencing with SIP
http://tools.ietf.org/html/rfc4353
Other Jitsi GSoC Projects
http://gsoc.jitsi.org
Jitsi Developer Documentation
http://www.jitsi.org/index.php/Documentation/DeveloperDocumentation
The official Jitsi website
http://www.jitsi.org