It is limitation in the camera source. It cannot generate 1920x1080 in 30 fps. Suggest use another USB camera which can support 30 fps.
I just check my capturing device. If it uses YUYU, yes, it only has 1920x1080 5fps.
Is it possible to use Motion-JPEG , MJPG instead? ‘MJPG’ has 1920x 1080 30fps
Yes, I bought another capture device and it works at 1920x1080 x 30fps.
Thanks for your help DaneLLL. :>