The term upstream user refers to the user who is currently publishing audio and video streams. After the user successfully publish the local stream by callingstartLocalVideo() | startLocalAudio() | startScreenShare(), the user becomes an upstream user. After the user unpublish the local stream by calling stopLocalVideo() & stopLocalAudio() & stopScreenShare(), the user is no longer an upstream user.
Limit on the Number of Upstream Users
The real-time audio and video backend server limits the number of upstream users in a single room to 50. If there are more than 50 upstream users in a room, the 51st user who attempts to publish a local audio and video stream will fail to publish. If the App business layer wants the 51st user to publish a local stream, it should first let other users stop publishing local streams by calling stopLocalVideo() to make room for the new user to become an upstream user.