Simulcast to improve Call Quality for Group Calling

In group calls with three or more users, Simulcast helps to preserve call quality and bandwidth in situations where one user with poor network conditions acts as the lowest common denominator and degrades the video experience for all users.

 

Simulcast is a technique by which a video feed is encoded with different qualities and sent to a selective forwarding unit (SFU). The SFU decides and sends the video feed with the optimal quality to each user based on the receiving user’s respective network. Lower resolution/bitrate content can be sent to the receiver on poor network and higher resolution/bitrate content can be sent to receivers on good network, thereby minimizing the impact of the lowest common denominator.

 

One common use case that demonstrates the benefits of Simulcast is a receiver on a large screen (e.g. desktop) in a call with another receiver on a small screen (e.g. mobile) will not be affected by the quality of the smaller view. Simulcast will send a higher resolution to the desktop receiver and a smaller resolution to the mobile receiver.

 

Learn more: Azure Communication Services Simulcast - An Azure Communication Services concept document | Microsoft Learn