Prototype Analysis of Video Conferencing Function

Open-source video conferencing software is currently not yet mature. Software-based solutions can be constructed using open-source libraries such as FFMPEG, X264, WebRTC, and others. The current MCU (Multipoint Control Unit) needs to support the following capabilities:

 

1. Web Interface: Manage conferences, status, external calls, and the removal of participants, among other functions.

2. SIP Module: Ability to interface with other SIP servers, such as Asterisk, FreeSWITCH, OpenSIPS, etc.

3. Video Support: H264, VP8, H263 series, and support for transcoding between these video formats.

4. Conference Templates: Support for predefined conference templates.

5. Conference Recording: Capability to record conferences.

6. Resolution: Support for resolutions up to 720P.

7. VAD Support: Utilizing WebRTC for Voice Activity Detection.

8. NAT Traversal: Support for STUN, ICE, and other NAT traversal techniques.

9. RTMP Protocol: Ability to stream conference media using the RTMP protocol.

10. FEC and NACK: Support for Forward Error Correction (FEC) and Negative Acknowledgement (NACK) to protect against video packet loss.

 

Video conferencing has transitioned from traditional MCU transcoding to the MCU Relay model, thanks to the emergence of the SVC (Scalable Video Coding) codec. This architecture significantly enhances the load capacity of MCU servers. Traditional MCUs were largely based on hardware transcoding, but with the advent of SVC, it is entirely feasible to implement a Relay-based MCU server using a software solution. Perhaps, at this point, the term MCU should be renamed to MRS (Media Relay Server).