cktool -s 参数为0，1都可以运行。但是如果是3以上就出错，encode出错，我已经安装了ffmpeg

出现如下问题：
+++ Capture opened
!!! Set crop to (0, 0, 640, 480) failed. Don't panic, not all capture device support crop!
!!! VIDIOC_S_INPUT failed
+++ Device initialized
+++ Capture Opened
+++ Convert Opened

• failed to open vchiq instance