gspca-kinect2-loopback.service

# https://github.com/yoshimoto/gspca-kinect2/pull/8#issuecomment-642292281

[Unit]
Description=Loopback to enable Kinect v2 compatibility with webcam applications.

[Service]
ExecStartPre=/bin/modprobe v4l2loopback video_nr=9 card_label="Kinect v2"
ExecStart=/usr/bin/ffmpeg \
    -i /dev/video0 \
    # don't do vsync, for less delay
    -vsync drop \
    # drop half the frames, and scale to 720p -- good enough for webcam use
    # also mirror horizontally for webcam use -- other cams do this intrinsically but we need to do it ourselves
    -filter:v fps=30,scale=1280:-1,hflip \
    # good general-purpose pixel format supported by many apps
    -pix_fmt yuyv422 \
    # convert the colorspace, so the colors look better (not blown out too much)
    -color_trc bt709 \
    -color_primaries bt709 \
    -color_range tv \
    # output device format
    -f v4l2 \
    # output device
    /dev/video9
SuccessExitStatus=255
Restart=always
RestartSec=2

[Install]
WantedBy=default.target