Connection issue in China

yusuke-takaku-60c97a

I am considering using Airelink to communicate with a customer in China, but I am facing what seems to be a communication issue and would like your advice. Specifically, the audio is fine, but the resolution of the video call and application screen is extremely poor. We have confirmed that the wifi we are using has no communication problems at all with Microsoft Teams.

petr_kazda

Hello, the quality is adjusted automatically based on the available bandwidth. In your case there may be an issue with the relay server than needs to route traffic through AWS datacenter in Frankfurt increasing latency and decreasing quality.

I would recommend to try different network as on other network there may be chance for P2P connection that does not use relay server. Ideally you can try 4G data or something similar.

yusuke-takaku-60c97a

petr_kazda
Thank you so much for your reply. I will try different network. By the way, can the app do something to reduce the frame rate in order to speed up the transfer rate over the network?

petr_kazda

Hello, by default WebRTC uses Opus and VP8 codecs which both supports adaptive streaming. Adaptive streaming means they are capable of changing resolution and/or framerate according to network conditions. The real implementation varies between browsers and overall it is non trivial problem where many factors comes into play. We are using state-of-the-art implementation that should work under most conditions.
The issue in China may be caused by the “great China firewall” that may throttle connection to TURN server. Solution would be to deploy TURN server instance directly in China, but that is potentially time consuming task to do due to China government requirements.

yusuke-takaku-60c97a

petr_kazda
Thank you very much for the detailed explanation, it helped me understand the situation.