ArchLinux ElGato FaceCam - Chrome V4L2Loopback

README.md

ArchLinux ElGato FaceCam - Chrome V4L2Loopback

IMPORTANT

This is not required any more, you need upgrade your firmware to the version +4.09 using ElGato Cammera Hub

https://help.elgato.com/hc/en-us/articles/4406041241997-Elgato-Facecam-Firmware-Update

Changes in firmware 4.09

• Added MJPEG as a fallback video format. MJPEG requires less USB bandwidth and improves compatibility with programs that cannot handle uncompressed video.

Loopback Config

I'm creating 3 Loopback devices, if you only need do this for the Facecam you can define only one like this:

options v4l2loopback video_nr=11 card_label="ElGato FaceCam"

WebCam Path

I'm using my serial as a path to not conflict with my another input devices /dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW42K1A07115-video-index0 on the facecam-init.sh.

You can check what is your correct path with this command:

ls /dev/v4l/by-id/

WebCam Config

On my facecam-init.sh, I set some parameters that make sense for my enviroment, this maybe cannot fit for you, so you can remove this line.

v4l2-ctl -d /dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW42K1A07115-video-index0 --set-ctrl="brightness=180,contrast=3,saturation=35,white_balance_temperature_auto=1,power_line_frequency=2,sharpness=1,exposure_auto=2,zoom_absolute=5"

or adjust the parameters that you want.

Run

You need start the script to create the pipe from the FaceCam Device to the LoopBack Virtual Device

• Add execution permissions:

chmod +x facecam-init.sh

• Run

./facecam-init.sh

facecam-init.sh

#!/bin/bash

v4l2-ctl -d /dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW42K1A07115-video-index0 --set-ctrl="brightness=180,contrast=3,saturation=35,white_balance_temperature_auto=1,power_line_frequency=2,sharpness=1,exposure_auto=2,zoom_absolute=5"

ffmpeg -f v4l2 -input_format uyvy422 -framerate 60 -video_size 1920x1080 -i /dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW42K1A07115-video-index0 -pix_fmt yuyv422 -f v4l2 /dev/video11

module.conf

# /etc/modules-load.d/v4l2loopback.conf
v4l2loopback

options.conf

# /etc/modprobe.d/v4l2loopback.conf
options v4l2loopback video_nr=10,11,12 card_label="OBS Virtual","ElGato FaceCam","V4L2Loopback" exclusive_caps=1,1,1

Is this working consistently for you folks? I'm using obs-studio and its virtual camera, but while it works for a while (and needs an occassional usbreset between sessions), it still hangs/freezes mid-stream. I can't get it to work for an extended period of time. This is regardless if using MJPEG, or the frame rate, etc.

Is this working consistently for you folks? I'm using obs-studio and its virtual camera, but while it works for a while (and needs an occassional usbreset between sessions), it still hangs/freezes mid-stream. I can't get it to work for an extended period of time. This is regardless if using MJPEG, or the frame rate, etc.

Using it all day with google meet, no issue here.

Sometimes, the camera will appear as unplugged on boot, but a quick physical disconnect/reconnect fixes the issue.

Is this working consistently for you folks? I'm using obs-studio and its virtual camera, but while it works for a while (and needs an occassional usbreset between sessions), it still hangs/freezes mid-stream. I can't get it to work for an extended period of time. This is regardless if using MJPEG, or the frame rate, etc.

I been using the camera with the new firmware consistently (Without this script) , however as @kouak mention sometimes the camera don't show up on boot (a quick disconnect and connect fix the issue). I think that happen because the cam have in the firmware some logic to detect if is connected to usb2 and show the device as something like "Connect this in a USB 3.0 port".

I'll check out the v4l2loopback method then. I'm already on the latest firmware but maybe this is some interaction with obs-studio.

I have up to date firmware but the camera cuts out, once you stop recording, no other app can get a stream working.

I tried this method, and it looks like this on my end:

# modprobe.conf
options v4l2loopback devices=1 video_nr=1 card_label="OBS Cam" exclusive_caps=1

These are options from the obs setup but OBS is not running to I tried to repurpose /dev/video1:

$ ffmpeg -f v4l2 -input_format uyvy422 -framerate 60 -video_size 1920x1080 -i /dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW49K1A04697-video-index0 -pix_fmt yuyv422 -f v4l2 /dev/video1
ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
  built with gcc 14.2.1 (GCC) 20250322
  configuration: --disable-static --prefix=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1 --target_os=linux --arch=x86_64 --pkg-config=pkg-config --enable-gpl --enable-version3 --disable-nonfree --disable-static --enable-shared --enable-pic --disable-thumb --disable-small --enable-runtime-cpudetect --disable-gray --enable-swscale-alpha --enable-hardcoded-tables --enable-safe-bitstream-reader --enable-pthreads --disable-w32threads --disable-os2threads --enable-network --enable-pixelutils --datadir=/nix/store/nbs8kinkznw795sbw5mabfn1980hjr8w-ffmpeg-7.1.1-data/share/ffmpeg --enable-ffmpeg --enable-ffplay --enable-ffprobe --bindir=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1-bin/bin --enable-avcodec --enable-avdevice --enable-avfilter --enable-avformat --enable-avutil --enable-postproc --enable-swresample --enable-swscale --libdir=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1-lib/lib --incdir=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1-dev/include --enable-doc --enable-htmlpages --enable-manpages --mandir=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1-man/share/man --enable-podpages --enable-txtpages --docdir=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ffmpeg-7.1.1-doc/share/doc/ffmpeg --enable-alsa --enable-amf --enable-libaom --disable-libaribb24 --disable-libaribcaption --enable-libass --disable-avisynth --enable-libbluray --disable-libbs2b --enable-bzlib --disable-libcaca --disable-libcdio --disable-libcelt --disable-chromaprint --disable-libcodec2 --disable-cuda --enable-cuda-llvm --disable-cuda-nvcc --enable-cuvid --enable-libdav1d --disable-libdc1394 --enable-libdrm --disable-libdvdnav --disable-libdvdread --disable-libfdk-aac --enable-ffnvcodec --disable-libflite --enable-fontconfig --enable-libfontconfig --enable-libfreetype --disable-frei0r --enable-libfribidi --disable-libgme --enable-gnutls --disable-libgsm --enable-libharfbuzz --enable-iconv --disable-libilbc --disable-libjack --disable-libjxl --disable-libkvazaar --disable-ladspa --disable-liblc3 --disable-liblcevc-dec --disable-lcms2 --enable-lzma --disable-metal --disable-libmfx --disable-libmodplug --enable-libmp3lame --disable-libmysofa --disable-libnpp --enable-nvdec --enable-nvenc --disable-openal --enable-opencl --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-opengl --disable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-libopus --disable-libplacebo --enable-libpulse --disable-libqrencode --disable-libquirc --disable-librav1e --enable-librist --disable-librtmp --disable-librubberband --disable-libsmbclient --enable-sdl2 --disable-libshaderc --disable-libshine --disable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --disable-librsvg --enable-libsvtav1 --disable-libtensorflow --enable-libtheora --disable-libtwolame --enable-libv4l2 --enable-v4l2-m2m --enable-vaapi --enable-vdpau --disable-libvpl --enable-libvidstab --disable-libvmaf --disable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-vulkan --disable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --disable-libxavs --disable-libxcb --disable-libxcb-shape --disable-libxcb-shm --disable-libxcb-xfixes --disable-libxevd --disable-libxeve --disable-xlib --enable-libxml2 --enable-libxvid --enable-libzimg --enable-zlib --disable-libzmq --enable-libzvbi --disable-debug --enable-optimizations --disable-extra-warnings --disable-stripping
  libavutil      59. 39.100 / 59. 39.100
  libavcodec     61. 19.101 / 61. 19.101
  libavformat    61.  7.100 / 61.  7.100
  libavdevice    61.  3.100 / 61.  3.100
  libavfilter    10.  4.100 / 10.  4.100
  libswscale      8.  3.100 /  8.  3.100
  libswresample   5.  3.100 /  5.  3.100
  libpostproc    58.  3.100 / 58.  3.100
# HANGS AT THIS POINT
# I have to CTRL+c just to get it to continue
Input #0, video4linux2,v4l2, from '/dev/v4l/by-id/usb-Elgato_Elgato_Facecam_FW49K1A04697-video-index0':
  Duration: N/A, bitrate: 1990656 kb/s
  Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1920x1080, 1990656 kb/s, 60 fps, 60 tbr, 1000k tbn
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
Press [q] to stop, [?] for help
# also hangs here, the only thing that kills it is ctrl+c three times

hangs in the two places I described.