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Questions tagged [v4l2loopback]

v4l2loopback is a linux kernel module to create V4L2 loopback devices. usage questions should be asked on "Unix&Linux".

If you are having troubles using the v4l2loopback module, you probably should ask on Unix & Linux instead.

Upstream: https://github.com/umlaeute/v4l2loopback

112 questions
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How to write/pipe to a virtual webcam created by V4L2loopback module?

I have written an application which reads from a webcam and processes the frames using OpenCV on linux. Now I want to pipe the output of my application to a virtual webcam that has been created by the V4L2loopback module so other applications are…
user477519
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GStreamer + V4L2loopback as Chrome compatible webcam

I am trying to create a virtual camera in Chrome using v4l2loopback where the incoming video is H264 via RTP. I have has some success in getting a GStreamer test video recognized in Chrome with MediaStreamTrack.getSources: $ sudo modprobe…
Ross
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1 answer

How to change mjpeg to yuyv422 from a webcam to a v4l2loopback?

Backstory: One livestreaming site I use isn't smart enough to detect the capabilities of my webcam (Logitech Brio, 4k), and instead just uses the default frames per second settings, which is 5fps. (full solution walk-through in the answer) The best…
Dev Null
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1 answer

Unknown V4L2 pixel format equivalent for yuvj420p

I am trying to pipe a mp4 video located in Videos/video.mp4 to a virtual webcam device located at /dev/video0. I tried running: ffmpeg -re -i Videos/video.mp4 -map 0:v -f v4l2 /dev/video0 and I keep getting the following error: [video4linux2,v4l2 @…
c10ud
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6
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2 answers

FFmpeg change output to specific pixel format?

I am working on an openCV project, I have a stable running variant that is taking input from an HDMI capture card and using FFmpeg to output to a v4L2 loopback device (/dev/video0) my openCV project takes its input from /dev/video0. The issue comes…
R.martinez
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3 answers

Dummy video device - v4l2loopback - webRTC

I need to play multiple video for test a video server. I'm using lubuntu 14.04 and have installed V4l2loopback to make the device file ( /dev/videoN ) I am using mplayer to play video from this device as described mplayer cam I have done the modify…
Al3
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2 answers

Running two v4l2loopback devices with their individual properties

Working with v4l2loopback devices I can run these two virtual devices: a) running the preview image from a Canon DSLR via USB through v4l2loopback into OBS: modprobe v4l2loopback gphoto2 --stdout --capture-movie | gst-launch-1.0 fdsrc fd=0 !…
Max N
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5
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5 answers

loopback "lb4" command is not working after successfully installation of loopback CLI using "npm i -g @loopback/cli"

I have successfully installed loopback CLI using npm i -g @loopback/cli after that I'm trying to create app using lb4 app command terminal and it shows me Command 'lb4' not found. Only lb app works for version 3 and 2 but I want to create…
ranjit redekar
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4
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2 answers

Google chrome cannot detect v4l2loopback device

I'm trying to transmit my screen using ffmpeg and v4l2loopback, more when running the commands: sudo modprobe v4l2loopback devices=1 video_nr=2 card_label="Camera Loopback" and ffmpeg -f x11grab -framerate 30 -video_size 1366x768 -i :0.0 -f…
Gabriel
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2 answers

v4l2loopback device detected by Chrome, not seen by Zoom or Firefox

I am trying to create a loopback device from my webcam to be accessible from both Zoom and a browser. I created three v4l2loopback devices: sudo modprobe v4l2loopback devices=3 video_nr=10,11,12 card_label="Loopback_1","Loopback_2","Virtual_cam"…
uri sh.
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1 answer

loopback 4 integration with socket.io

I'm working on a project which is built on loopback 4, and now the client is asking to have notifications and messaging. I searched a lot to find the best way to integrate socket.io with loopback 4, no luck, I found nothing Any ideas?
Raeef Refai
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How do I add a delay to a live stream sourced from webcam (v4l2) with FFMPEG?

How can I use FFMPEG to add a delay to a stream being sent from a (v4l2) webcam to a media server? The use case here is something like a security camera where I want to be able to stream video to a server when something is detected in the video. The…
David
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modprobe: ERROR: could not insert 'v4l2loopback': Unknown symbol in module, or unknown parameter (see dmesg)

I am trying to set up virtual v4l2 devices on an AWS EC2 instance. I did apt install for v4l2loopback-dkms and v4l2loopback-utils. I get the following error when i try to set up devices with sudo modprobe v4l2loopback device=8 modprobe: ERROR: could…
k0342
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Stream static image to v4l2loopback using obs with v4l2 plugin, ffmpeg or gstreamer

I want to stream a static image to the android studio emulator. To do that I created a virtual camera using v4l2loopback v.12.5 in linux ubuntu 20.04. The virtual camera is created in /dev/video2. I can stream there using obs and a plugin, ffmpeg or…
ykasur
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3
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1 answer

v4l2loopback doesn't create the /dev/video/ files

im trying to make v4l2loopback work on my desktop PC (no hardware camera) with mint 19.3, kernel 5.4.0-42-generic x86_64. I followed the official instructions and compiled from git the v4l2loopback module and everything seem to run correctly, as no…
KiraraVS
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