将usb uvc摄像头作为默认摄像头,需要如何修改

ls -la /dev/v*
0 crw-rw-r-- 1 bluetooth net_bt 10, 48 2013-01-18 08:50 /dev/vendor_storage
0 crw-rw---- 1 media camera 81, 0 2013-01-18 08:50 /dev/video0
0 crw-rw---- 1 media camera 81, 1 2013-01-18 08:50 /dev/video1
0 crw-rw---- 1 media camera 81, 2 2013-01-18 08:50 /dev/video2
0 crw-rw---- 1 media camera 81, 3 2013-01-18 08:50 /dev/video3
0 crw-rw---- 1 media camera 81, 4 2013-01-18 08:50 /dev/video4
0 crw-rw---- 1 media camera 81, 5 2013-01-18 08:50 /dev/video5
0 crw-rw---- 1 media camera 81, 6 2013-01-18 08:50 /dev/video6
0 crw-rw---- 1 media camera 81, 7 2013-01-18 08:50 /dev/video7
0 crw-rw---- 1 media camera 81, 8 2021-01-19 04:21 /dev/video8
0 crw-rw---- 1 media camera 81, 9 2021-01-19 04:21 /dev/video9
0 crw-rw-rw- 1 root root 10, 55 2013-01-18 08:50 /dev/vndbinder
0 crw-rw-rw- 1 media media 244, 0 2013-01-18 08:50 /dev/vpu_service

video8,video9是usb摄像头,其他的摄像头都没插,0-7一直存在,默认的程序调用的是video0和video1,我想把外置的usb摄像头改为video0和video1 需要怎么修改呢?