Can't access webcam settings

I am using Ubuntu 18.04.4 LTS, Gnome version 3.28.2. I am struggling with my built-in webcam. I can use it with Zoom, but I can't seem to find how to change the webcam settings; I suspect I may have deleted something important when I was trying to "clean up" my computer. Specifically, I'd like to be able to zoom out since it shows an XL version of my face when I have the computer close enough to type on. The colors are fine.

According to the Zoom settings, it is using "Camera: USB2.0 VGA UVC WebCam: USB2.0 V". In the attached screenshot I've hidden my face for privacy, but you can see the list of settings and that the color is working correctly.

Zoom settings and camera example

I went to my application list for programs on my computer and didn't see anything related to webcam, camera, etc.

Ubuntu program list page 1

Ubuntu program list page 2

I tried running from my terminal sudo apt-get install --reinstall xorg; it didn't throw any errors but it also didn't fix the problem (didn't seem to change anything).

I went into my Ubuntu settings but there didn't seem to be anything there about cameras.

Ubuntu settings list

Based on Ubuntu's webcam help page (https://help.ubuntu.com/community/Webcam), I tried entering in my command line: ls /dev/video* and got /dev/video0 /dev/video1. Great, looks good. Then I tried entering vlc v4l2:///dev/video0 from later in their instructions and I got:

/usr/share/libdrm/amdgpu.ids: No such file or directory
VLC media player 3.0.10 Vetinari (revision 3.0.10-0-g7f145afa84)
[00005603e0c8aa00] main libvlc: Running vlc with the default interface.
Use 'cvlc' to use vlc without interface.
Qt: Session management error: None of the authentication protocols specified are supported
/usr/share/libdrm/amdgpu.ids: No such file or directory
[00007f30a00010e0] v4l2 demux error: cannot open device '/dev/video0': Operation not permitted
[00007f30a00010e0] v4l2 demux error: cannot open device '/dev/video0': Operation not permitted
[00007f30a0002750] v4l2 stream error: cannot open device '/dev/video0': Operation not permitted

Edit: Hi @sc608, I installed guvcview as you suggested. However, when it installed the video was already zoomed out all the way, as shown here

gucview screenshot

and my face is not any larger. The Zoom video still looks the same unfortunately.

I am not sure if it will solve your issue with Zoom but the package guvcview contains zoom controls for most webcams. The package is in the Ubuntu repos and can be installed with sudo apt install guvcview. Once installed it will appear in your list of applications.

The application launches in two windows. One window is the view from your webcam the other is an extensive assortment of webcam controls including zoom. I hope this helps solve your issue.

There's a handy CLI tool to control webcams in ubuntu: v4l-utils.

Install

sudo apt install v4l-utils

Find you webcam

you might have multiple. Also, for some reason, it may list two devices per camera, pick first.

v4l2-ctl --list-devices

The output should be something like

HD User Facing: HD User Facing (usb-0000:05:00.3-1):
    /dev/video1
    /dev/video2

BRIO 4K Stream Edition (usb-0000:05:00.3-4):
    /dev/video3
    /dev/video4

Tweak

Get Controls

Let's see what we can control

v4l2-ctl -d /dev/videoX --list-ctrls  # X -- for your device number

The output should be something like

                     brightness 0x00980900 (int)    : min=0 max=255 step=1 default=128 value=128
                       contrast 0x00980901 (int)    : min=0 max=255 step=1 default=128 value=128
...
                     focus_auto 0x009a090c (bool)   : default=1 value=1
                  zoom_absolute 0x009a090d (int)    : min=100 max=500 step=1 default=100 value=100

Example: zoom in

v4l2-ctl --device /dev/video3 --set-ctrl=zoom_absolute=120

I had the same problem. The solution was to change a setting in Zoom. Zoom then respected the tweaks made in guvcview, including camera zoom.

Zoom > Settings > Video > Camera > Original ratio: Checked

OP screenshot shows the opposite setting (Original ratio: Unchecked).

I also have this problem. Using guvcview normally works as mentioned by sc608 & james-h. However in Zoom the behaviour is erratic. It seems that when changes happen in Zoom (eg someone new enters the meeting, or a breakout room) the image from my webcam changes back from the original ratio to full zoom. I have to manually go to the settings, turn off "Original Ratio" and then turn it back on again. I'm not sure if this is an issue with guvcview or Zoom.