Low quality for two people when use videobrige

Hi, I got some trouble with the bandwidth I had when use lib-jitsi-meet and join room with 2 people through videobridge. The first person will get low downloading bandwidth after the second come in. What is the problem?

Do you wait for them to ramp-up? Do you select the participant that joined video to inform jvb to send you high resolution stream?

Ya, my custom UI call function selectParticipant to get higher resolution stream