Having the same issue.
OS: Windows 10 (1909)
CPU: Intel J2900 @2.4GHz (Quadcore)
RAM: 4 GB
Webcam: Logitech C270
As soon as the Jitsi meeting starts, the Video Capture process shows up with a high CPU load in Chrome Task Manager (Shift ESC). This is already the case when I’m the only one in the meeting.
When the someone joins, the CPU load of the Video Capture process increases slightly and the CPU load of the tab Jitsi Meet also goes up a lot.
On this PC this makes using Jitsi with video unuseable.