Hello, everyone. I want to share a knowledge of factors of an IP Network That Affect Videoconferencing Services-Jitter

Jitter is the variation in the delay as measured in the variability over time of the packet delay across a network. When data packets are sent to a destination over the network at an interval, the destination may fail to receive the packets at this interval due to network congestion or device processing. For example, the destination does not receive packets in a period of time or receives multiple packets at the same time.

The audio and video must be collected and displayed continuously for video conferences. A large jitter greatly decreases the audio and video quality of videoconferencing services, with the symptoms of discontinuous audio, frozen pictures, fast-forwarded pictures, and video artifacts.

An example is as follows:

Description:

1.       At the 45th millisecond, network congestion causes a jitter and no packet is sent to the endpoint.

2.       The endpoint has no packet to decode and simply displays the last audio and video.

3.       At the 60th millisecond, the delayed packet and new packet arrive at the endpoint together.

4.       The endpoint decodes packets 3 and 4, displays video 4, but discards video 3 because it can have only one frame output at a time. As a result, frozen pictures or discontinuous audio occurs. (Endpoints and the MCU have anti-jitter capability (80 ms by default). However, packet loss still occurs if an endpoint or an MCU receives too many packets at a time which exceed the buffer area.

Conclusion

The above scenarios are completed in the laboratory environment, If you have any questions, welcome to reply and exchange, looking forward to your reply and good comments. thank you.