Manually upgrading an outdated v4l2loopback-src on Alpine Linux

placeholder snippy one-liner, as I couldn't think of one at the time

• Updated 2024-09-21

Similar to OBS, sometimes I want to update a package before it gets updated upstream (if ever). I use the v4l2loopback-src package to build kernel modules to support v4l2loopback devices, mainly for droidcam/droidcamX on android and droidcam-gui on Alpine, to use my android phone's camera in OBS.

V4l2loopback fails to build for me on recent linux-edge kernels (6.9+) for version 0.13.2 (the current version as of this writing). LTS kernels still work fine, for now, but are on 6.6+ kernel versions.

What does work for me is a manual download and install from git, so I will do that until the actual package fixes itself somehow.

tl;dr

# Clone the git repo; read the readme for better and more detailed
#   instructions
git clone https://github.com/umlaeute/v4l2loopback && cd v4l2loopback

# (Optional) Good to do after kernel upgrade, clean install
make clean

# Make and install
make && doas make install

# Modprobe the kernel module
doas modprobe v4l2loopback

# Droidcam should now work to send to a /dev/videoX device
# droidcam &

# (Optional) create/edit config file in ~/.config/droidcam
# e.g. I changed the "size=" value to 3840x2160 to work with 4K from the
#   DroidCamX Android application on my phone.