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Questions tagged [v4l]

Video4Linux is the linux kernel video capture subsystem, with a set of userland utilities.

2
votes
1answer
101 views

Get video device on embedded Linux SoC

I'm trying to find the camera module device of an IP camera (running Linux), without much success. My main objective is to find the camera stream, so I can attach an RTSP server. Update 26/02/2019 ...
0
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0answers
55 views

Simulating UVC webcam from v4l2loopback stream

Is there any way to emulate a USB camera device (UVC) from my v4l2loopback stream at /dev/video0, so my linux can recognize it as a real USB device?
1
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0answers
113 views

When i plug in usb camera i get 2 devices

When I plug in the camera to Linux then I get 2 devices /dev/video0 and /dev/video1 Why is that happens and is that normal? Odd numbered devices do not work. /dev/v4l/by-path looks like that: ...
2
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0answers
36 views

Webcam and Desktop composite with v4l2loopback?

Is there anyway to do a composite video setup where the webcam is overlain onto the desktop and output as a video device (simulated webcam)?
0
votes
1answer
142 views

Using Roxio VHS to DVD 3 Plus on Arch Linux

I bought https://www.roxio.com/en/products/easy-vhs-to-dvd/standard/ with the goal of converting VHS tapes to a digital format. https://superuser.com/questions/234026/video-from-vhs-via-usb-capture-...
0
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0answers
14 views

Unable to crop camera input using standard v4l tools

I need to crop my camera input for usage with Skype/hangouts (unfortunately all cameras are "wide angle", nowadays). I tried several ways, most notably using qv4l2; here the "Cropping & Compose ...
1
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0answers
205 views

v4l2loopback Devices Not Showing Up In Linphone 'webcam list'

My setup: Raspberry Pi 3 (armhf) Raspbian Jessie (basically Debian) Kernel 4.4.13-v7+ I'm not using the Raspberry Pi for anything other than convenience of a testing platform. The hardware could be ...
2
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0answers
349 views

Use guvcview to setup Logitech C920 webcam and keep configuration

I have a Logitech C920 webcam connected to my computer running Debian Linux. I want to access the stream by using mplayer (/dev/video0) and it works out of the box. However, the saturation/brightness/...
1
vote
1answer
86 views

How can I have concurrent read access to video devices on Linux?

I want to be able to have multiple readers on a video device file - one using it to stream video and another using it for computer vision processing. How can I do this?
0
votes
1answer
280 views

webcam - xawtv & mplayer

Folks, I am running through a weird problem. I am running Debian stretch on my thinkpad t430. When I try to capture video using my integrated webcam, I am able to view a streaming video, if I xawtv -...
1
vote
0answers
88 views

Live capable highspeed camera for Linux?

I am tasked to set up a number of highspeed cameras on top of a foosball (? aka. table soccer ?) table to allow for slowmotion replay of interesting moves and goals. So far a test setup is ok by all ...
2
votes
1answer
1k views

Understanding media-ctl output

I am working with a Dragonboard410c and I am trying to using a gstreamer pipeline to generate an mp4 video from a Logitech C270 USB camera. For this task I am following the instructions reported here ...
2
votes
1answer
1k views

Adding and removing v4l2-loopback devices?

I have different lxc containers running on my machine and a webcam is also attached. I want all of the lxc containers to access this camera. I came across 'v4l2-loopback' devices and found a way to ...
1
vote
1answer
644 views

Adjusting keyframe rate ffmpeg/v4l2 Logitech C920 to YouTube Live

I am trying to stream video from a Logitech c920 to YouTube live via ffmpeg. I have a setup that works in Twitch, but YouTube rejects the stream with the message: Please use a keyframe frequency ...
1
vote
0answers
489 views

ffmpeg with v4l2, scale and still use OpenMAX hw acceleration

I got ffmpeg compiled with OpenMAX encoding acceleration support on RPi--yay! Now my problem is, I'm working with a protocol that insists on specifying its required resolution. As soon as i specify -...
2
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0answers
125 views

What is the proper encoding for a v4l device, what chromium can accept?

I use uv4l driver for Raspberry Pi Camera Module V2, which gives me the possibility to choose the encoding, framerate etc... The following encodings were tested: yuv420, nv21, yvu420, rgb565, ...
1
vote
1answer
494 views

Linux video capture does not work cam3 or Image capture in cam1 fails

I am trying to some solution or run-time fix on this. Problem: After connecting a 3rd camera, Linux video capture does not work cam3 or Image capture in cam1 fails. History: Initially, we ...
1
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0answers
2k views

IDS uEye camera stream

I am using an IDS uEye XS USB camera (https://en.ids-imaging.com/store/produkte/kameras/usb-2-0-kameras/ueye-xs.html) and my problem is that according to the sdk description it does not have V4L or ...
0
votes
1answer
782 views

v4l2-ctl error in script

I can use v4l2-ctl in command line like these: v4l2-ctl -d /dev/video1 -c focus_auto=0 v4l2-ctl -d /dev/video1 -c exposure_auto=0 But it has error when I run them as a script in a file. for example ...
2
votes
1answer
1k views

release/close capture of camera

I have opened webcam for capturing using OpenCV in C++. Then I stopped the program using CTRL+Z; The webcam could not turn off, Because was not defined in program. And I can not start my program ...
4
votes
0answers
2k views

Chroma key (green screen) live for a webcam?

Is there a way to apply chroma key live to a stream that's used in video conferencing. Webcam works fine though v4l (Cheese, Ekiga). This but in Linux.
6
votes
1answer
4k views

How to create dummy webcam?

I would like to join some videoconference, but I don't own a webcam and the conference software requires one. So my question is, can I create a dummy one? I don't care what the cam will cast, I just ...
2
votes
0answers
596 views

Motion command images are jibberish

It seems my motion command config will not take complete pictures. It used to take a few tiny ok images, and a garbled image, now after adjusting it to full resolution it takes a large image of ...
2
votes
0answers
2k views

How to record v4l webcam with ffmpeg? Cannot find a proper format for codec 'none'

Goal is to capture video from my old usb webcam (device 0733:0430). Trying to save video gives this error. (I've tried both ffmpeg and avconv.) Command ffmpeg -f v4l2 -i /dev/video2 -s 160x120 tmp....
1
vote
0answers
359 views

cheese doesn't work in beagleboneblack installed with angstrom, using chipsee LCD

I am using chipsee LCD + beaglebone black and Logitech Webcam C270. I am using the Angstrom OS distribution provided by Chipsee. I wanted to use Cheese to see if the webcam works fine or not. When I ...
8
votes
2answers
9k views

Understanding webcam 's Linux device drivers

As far as I know, device driver is a part of SW that is able to communicate with a particular type of device that is attached to a computer. In case of a USB webcam, the responsible driver is UVC ...
1
vote
1answer
6k views

Install kernel module [V4L2]

In order to build and install V4L2 module, do I have to download it, or it is already part of the kernel (and all I have to do is to choose it, in order to build it, via kernel configuration)? I 'm ...
11
votes
3answers
31k views

How do I find out which process is using my V4L2 webcam?

I tried to run the following: $ vlc -I dummy v4l2:///dev/video0 --video-filter scene --no-audio --scene-path webcam.png --scene-prefix image_prefix --scene-format png vlc://quit --run-time=1 ...
0
votes
1answer
875 views

Multiple FM radio streams from /dev/radio* via v4l2, ices2 and icecast

I have an FM radio USB dongle (Silicon chip), I have managed to stream the radio reception via icecast using the following configuration: the USB dongle is recognized by v4l2 driver and mounted at /...
0
votes
1answer
3k views

Video4Linux installation [closed]

I 'm running Angstrom distribution (console only) on BeagleBoard-xM. Image was build on Narcissus, with Bootloader Files (x-load/u-boot/scripts) added. I want to connect a USB webcam (Logitech Pro ...
1
vote
1answer
2k views

Trying to make my default selection for USB c920 webcam work in Gstreamer, but still opens laptop internal cam

For the past week I have been trying to get my Logitech c920 to act as my default webcam. Despite everything seeming to be in order, it's just not working. I have GUVCview and V4L installed. I have ...
2
votes
0answers
174 views

Hauppage WinTV USB 40001

I have tried, unsuccessfully, to hook up my (very old) video capture device. I have tried making it work with tvtime, but to no avail. I've tried sending messages to th e dsitribution list but I've ...
2
votes
1answer
3k views

Capture raw image from V4L (webcam) device

I'm using a Raspberry pi to monitor a self-service fridge. When the door opens, a shell script is being executed to capture pictures until the door closes again. The problem, however, is the speed of ...