# presence-detect.sh mirrors the real webcam into this virtual device so its
# 20s-interval motion checks never contend with other apps (Zoom, howdy, ...)
# for exclusive access to the physical camera.
#
# video_nr is fixed so the device always lands at /dev/video42, regardless of
# how many physical webcam nodes (including UVC metadata nodes) get enumerated
# first at boot.
#
# exclusive_caps=1 makes the device report standard single-purpose webcam
# capabilities, which most capture apps (ffmpeg, OpenCV, browsers) expect.
options v4l2loopback video_nr=42 card_label="presence-loopback" exclusive_caps=1