[SOLVED] Logitech C270 webcam problems with guvcview

kenb1000 · 02-11-2017, 11:53 AM

Greetings:

I'm trying to get my Logitech webcam working with guvcview but not having much luck. The green light on the camera lights up when I launch guvcview and I get audio but the video window is black. I tried plugging the camera into all of the various USB slots on the computer - front, rear, USB powered hub, and USB 3.0 expansion card. I also tried adjusting the video settings using Video4Linux control panel and in the application as well, as one person reported that lowering the contrast setting solved the same problem.

I can get video using VLC but the quality is pretty bad and no audio. I've stayed away from Cheese because many users seem to have problems with it.

The camera works fine on Windows 7 using the Logitech software but I'm trying to depend on Windows as little as possible these days.

I'm currently running Mint 17.3

Any advice will be appreciated. Thanks.

Shadow_7 · 02-11-2017, 12:19 PM

I have that webcam. Works great. And you can turn that light off.

Code:

$ uvcdynctrl --device=video1 --set 'LED1 Mode' 0
$ v4l2-ctl --device=/dev/video1 --set-fmt-video=width=1280,height=960,pixelformat=MJPG --set-parm="5"
$ mpv --ao=null --vo=opengl --demuxer-lavf-format=video4linux2 /dev/video1

And various other ways to use the webcam. You might check the settings on guvcview and select auto where possible.

Shadow_7 · 02-11-2017, 12:21 PM

On my laptop guvcview defaults to the built in camcorder (/dev/video0). Which shows up green because I have a dollar bill folded over the lens to block it's view.

kenb1000 · 02-11-2017, 12:46 PM

@Shadow 7: Thanks for the reply. All the auto boxes are checked (I only see two). Does the green light have any effect on whether or not I get video?

Shadow_7 · 02-11-2017, 12:47 PM

Quote:

Originally Posted by kenb1000

@Shadow 7: Thanks for the reply. All the auto boxes are checked (I only see two). Does the green light have any effect on whether or not I get video?

No. But it will reflect off a window if you have it pointed out one. And required to be on by law if you are recording, depending on region.

kenb1000 · 02-11-2017, 12:57 PM

Interesting. I suppose that light is for people walking into a room to let hem know they're being recorded.

Shadow_7 · 02-11-2017, 07:02 PM

The /dev/video# is assigned to the video group, so if your user isn't in that group, might be why you're seeing black.

$ groups

kenb1000 · 02-11-2017, 07:27 PM

When I run that command I get the following output:

adm cdrom sudo dip plugdev lpadmin sambashare debian-tor

I ran:
$ useradd -G video {my user name}

Results:
useradd: user 'my user name' already exists

I assume that means I'm in the video group?

Shadow_7 · 02-11-2017, 07:48 PM

Groups are changed with "usermod". Also, you need to be root the change permissions, and relog to have the changes take affect.

$ sudo usermod -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,debian-tor,video,audio {my user name}

Sefyir · 02-11-2017, 08:03 PM

Quote:

Originally Posted by Shadow_7

Groups are changed with "usermod". Also, you need to be root the change permissions, and relog to have the changes take affect.

$ sudo usermod -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,debian-tor,video,audio {my user name}

You may also use gpasswd.

Code:

       -a, --add user
           Add the user to the named group.

eg

Code:

gpasswd -a your_username your_group

kenb1000 · 02-11-2017, 08:07 PM

Well, unfortunately that did not work. Have audio and still no video. Rebooted and changed USB slot. Tried fiddling with the brightness and contrast.

Any other possible solutions you can think of?

kenb1000 · 02-11-2017, 08:09 PM

Will try your other suggestions and let you know.

Thanks.

kenb1000 · 02-11-2017, 08:15 PM

@Sefyir: Thanks for your reply. Ran the command and I was successfully added to the group but problem persists.

kenb1000 · 02-11-2017, 08:51 PM

OK - problem solved.

I originally installed guvcview using the Synaptic Package manager. I tried uninstalling and reinstalling the same way but no difference. So I decided to uninstall and then reinstall using PPA. Now everything works. My guess is that Synaptic installed an older version which for some reason my system did not like.

Thanks to all for you help. I did learn a few things.