Questions tagged [v4l]

video capture and output device API, also driver framework for the Linux kernel, which supports many USB-webcams, TV-tuners, and many other devices.

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Kernel Warnings Using V4L2 in Server 20.04

I have recently upgraded my server from Ubuntu Server 18.04 to 20.04. I have a video capture card which was working fine in 18.04 but now causes a kernel warning on every capture: Although it then ...
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Suddenly unable to install anything after failing to install v4l2loopback-dkms - dpkg insists I must first reconfigure UEFI Secure Boot

Fresh install of 21.10. I decide to install OBS Studio. The guide on https://obsproject.com/wiki/install-instructions#linux says If you want virtual camera support you need v4l2loopback-dkms ...
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Nothing happening after libcamera build?

I am very new to this, so please don't think I am an idiot. PC Model: Thinkpad X1 Tablet Gen 2 I have built libcamera... installing Meson and building with Ninja. My webcam has not worked for a while ...
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Webcam is flipped upside down in Asus, how to run MS Teams via LD_PRELOAD v4l1compat.so?

My webcam is flipped upside down in Asus K52. A year ago there was a working solution to make Teams Activator with added Exec command leading to Teams through libv4l: Exec=env LD_PRELOAD=/usr/lib/...
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Skip Authenticating OBS Virtual Camera

I just installed OBS 27.1.3, and, having used OBS 25.x.x, I was surprised to see that they added a Start Virtual Camera button. This is very useful, but mildly annoying when I want a virtual camera in ...
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My Kodicom 4400R Camera cards are not working after upgrading to 20.04LTS server

These cards were working under a 16.04 server but that server died so I built up a new box running 20.04 and, when I install the cards, they don't work. I was trying to view the camera with zoneminder ...
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v4l2loopback module failing on Ubuntu 20.04

I am trying a new web camera on a workstation that hitherto had no video capture devices attached. It should be plug-and-play but none of the programmes is able to find the camera once connected. ...
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Cam Link 4K - was working, but now it isn't

20.04 on a Lenovo X1 carbon, if it matters I have a Cam Link 4K USB HDMI adapter, the purpose of which is to connect the HDMI output of a camera to a USB input. I have managed to get it working in the ...
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2 votes
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Use custom video to feed camera

What I am trying to achive is to redirect my camera /dev/video0 with a custom video file. Desired Reasult: When opened a application like cheese or websites like jitsi which process the buffer from my ...
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3 votes
2 answers
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Troubleshooting trying to use Canon DSLR as webcam

I'm following this guide trying to use my Canon EOS 550D as a webcam. It is listed as supported by gphoto2. So, I connected my Canon to my laptop using a USB-cable, and I had no problems running $ ...
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How to forcefully remove v4l2loopback kernel module?

I am using ipwebcam-gst to use my phone as a webcam. Sometimes, it does not correctly close the v4l2loopback module (e.g. when the phone was accidentally disconnected), and when I try to remove the ...
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Built-in camera not working on Ubuntu 20.04.1

I have this consistent problem, since Ubuntu 16... The camera on my laptop is just not working. I have this problem since 4 years, I tried every solution google has, and i check regularly for any new ...
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C270 webcam keeps freezing in both cheese and teams

I've bought a Logitech webcam c270 for my online course, for some reason the university uses Teams. Both Teams and the C270 are compatible in my ubuntu 20.04. The webcam works pretty well until it ...
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3 votes
2 answers
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Apps not using full webcam resolution on Ubuntu

I bought the webcam Grandstream GUV3100 which is Full HD capable (1080p video at 30fps) but all the apps for videoconferencing, such as Discord, MS Teams, or Jitsi use only 720p stream from the webcam....
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v4l2loopback device not working with gstreamer

I'm on Ubuntu 20.4.1. I followed the instructions on https://github.com/umlaeute/v4l2loopback e.g. sudo modprobe v4l2loopback to set up a loopback device which I then can also find under ls /dev/video*...
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Why are my colors separated/shifted when using obs/v4l2sink/v4l2loopback?

Im using OBS with v4l2sink and v4l2loopback to edit my video for a remote trainig. The preview in obs looks fine, but the video has some serious color shifts in any tool I try to display the ...
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16 votes
4 answers
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Customizability of (Logitech Brio 4K Ultra HD) Webcam on Ubuntu

Can you control things like viewing angle, zoom, fps, and video resolution for a webcam connected to Ubuntu, through a standard set of commands or API? As a case in point, the Logitech Brio 4K Ultra ...
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how to use ipu3-cio camera in linux

I have a Thinkpad X1 Tablet (gen 2) with a front and back integrated camera running Ubuntu 19:10. The cameras appear to be detected: $ v4l-info v4l2 device info [/dev/video0] general info ...
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Virtual webcam with video4linux2 not available in some videochat services [duplicate]

I am trying to use my Canon 7D as a webcam on Kubuntu 19.10. I managed to connect the camera using gphoto2 and pipe the video stream to a video device with this following command: gphoto2 --stdout --...
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24 votes
6 answers
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Use webcam from laptop on desktop pc

I want to use the webcam on my laptop as video device on my pc to use it for video conferencing etc. So I not just want to stream the video. I actually want to "stream" the entire device over network....
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PS2 Eye Toy and Cheese webcam app

I have a Sony PS2 Eye Toy USB Camera. $ lsusb | grep Sony Bus 003 Device 002: ID 054c:0155 Sony Corp. When I plug it into a Ubuntu 18.04 machine, and start Cheese, then no devices are found. vlc ...
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Skype doesn't recognise v4l2loopback + gstreamer

I recently bought a full HD webcam and I'm running into some troubles using it on Ubuntu 19.10. The main issue is that I get very low fps (about 5-7) unless I run the webcam on relatively low ...
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v4l2 How to trigger automatic exposure adjusting?

I have automatic exposure set, but it reacts very slowly and sometimes not at all (but with cheese it works fine). I'm taking timelapse pictures with following command: ffmpeg -f video4linux2 -s ...
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VideoCapture.read() using OpenCV. Why is USB Camera faster than CSI Camera? (NO GPU)

I am using NanoPi Duo 2 for the real-time image acquisition project. I have noticed a significant performance (speed) difference between using CSI camera and USB camera. The performance difference ...
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4 votes
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Supply correct pixel format & parameters from gphoto2 feeding into ffmpeg using v4l2loopback

I have Nikon D3300 camera and want to feed video output into my computer as part of live streaming with OBS. I successfully installed v4l2loopback as well as gphoto2 on my Ubuntu 18.04. I already had ...
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USB video grabber works with camera, not with VHS recorder

I'm trying to get rid of all my old videotapes using a USB grabber (Fushicai USBTV007 Video Grabber [EasyCAP]). When I use VLC or Open Broadcaster Software I can get the video stream from /dev/video2. ...
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1 vote
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Analog video capture (Hauppauge Live USB) Error - vidioc_qbuf: message too long

I know about Hauppauge 610 Analog Video Capture Script or Command and Script to Capture VHS Tapes Using the Hauppauge 610 USB-Live 2 Analog Video Digitizer and Video Capture Device. I run their ...
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4 votes
1 answer
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gspca_zc3xx webcam does not work with skypeforlinux

I have an old Creative NX Pro webcam. In short, guvcview and v4l2ucp work perfectly; cheese can't find the webcam; and Skype can find the webcam but shows a black screen. Diagnostics: $ cat /etc/lsb-...
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Run script when virtual camera is turned on

I know that using the v4l2loopback it is possible to create a virtual webcam or video device, which we can feed by sending streams using tools like ffmpeg. It would be very nice to run a script ...
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2 votes
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"No space left on device" issue in using multiple cameras

When I try to capture video from two usb (uvc) cameras connected on a single usb port, there is an error: libv4l2: error turning on stream: No space left on device Unable to start capture: No space ...
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2 answers
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asus webcam is flipped upside down everywhere [duplicate]

I've been having this problem and I haven't been able to solve it for days now. It should be very simple, but I'm also very much a novice. My webcam is flipped upside down. Tried flipping it back ...
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1 vote
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Avermedia AverTV Volar HD 2 Model TD110

recently I bought this card, and there is no way to have it working in Linux Mint. Looking at the windows inf file, looks like the card uses the IT9135 driver [Strings] AVERMEDIA = "...
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2 votes
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Trying to get a RTL2832U DVB-T and a TBS 5922SE DVBS2 DVB-S2 to "cohabit"

Trying to get two DVB devices working at the same time and struggling. One's a TBS 5922SE, which is a dvb-s device and is now working and the other is a RealTek RTL2832U, a dvb-t, both USB. The ...
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1 vote
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Polaris AV Capture USB analog TV device drivers needed

I already have a Mecer-branded USB analog TV tuner that I've been using under Windows. Now that I'm moving to Lubuntu I'd like to use it there as well. The product's minimalistic web page is here. ...
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1 answer
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How to assign a fixed device number to a camera?

I need my usb video camera (A4Tech) to take /dev/video0 and the capture card (analog converter) to take /dev/video1 regardless of the order I connect them to PC.
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Problems with Logitech Orbicam webcam image

I have a problem with this webcam (ID - 046d:0892, driver gspca) on Acer Travelmate 8200 with Ubuntu 14.04. When using cheese or skype with preloaded v4l1compat.so library, it has bad image - it has ...
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4 votes
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avconv pipe to v4l2loopback device

I use v4l2loopback module to create two video device. My intention is to pipe output from primary video device to these two virtual devices. I can do that using ffmpeg: ffmpeg -f video4linux2 -s ...
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1 vote
1 answer
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Error while compiling OpenCV in Ubuntu 14.04

I followed the instructions for compiling opencv2.4.9 from Install OpenCV 2.4.9 in Ubuntu 14.04, 13.10 I am getting the following error during the build process. Can someone point out to me how to ...
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1 vote
1 answer
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How can I work out what v4l2 driver/module my webcam is using?

I've got a fault with how my webcam is being handled (awful framerate). I'd like to diagnose this and possibly dig into the code but I can't tell which v4l2 driver the thing's actually using. How do ...
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