More VLC woes

[Prexy]

Since I have two installs (one desktop and one laptop) that are essentially identical, it is confounding to me that I can open a webcam on one computer and not the other. Trying to look at file differences between the two, I got a more confusing situation. The working version (laptop) opens a stream from the webcam and briefly the screen shows "v4l2://" On the desktop, trying the same webcam gives me the error that I cannot open "MRL v4l2://" BTW, I have one usb webcam that I move back and forth between these computers.

Looking for the files or location in question, I see the desktop has many, many more files in the v4l2 directory, including a half dozen rpm files. I cannot delete these. Yast says it has deleted them but they remain. Dolphin will not give me the option to delete when I right-click on them. I copy the file names (copy, not type) to try zypper rm. Zypper says no such file, even though I'm looking at it. All the files/folders related to v4l2 on both machines are owned by root. I was thinking I could delete the v4l2 folder and it would recreate itself properly somehow, even if I had to download some rpm's again. Still that scares me as a sledgehammer approach that might not even work.

So, even if I can't get the webcam working, I'd like to know why these rpm files are permanent.

[deano_ferrari]

Since I have two installs (one desktop and one laptop) that are essentially identical, it is confounding to me that I can open a webcam on one computer and not the other. Trying to look at file differences between the two, I got a more confusing situation. The working version (laptop) opens a stream from the webcam and briefly the screen shows "v4l2://" On the desktop, trying the same webcam gives me the error that I cannot open "MRL v4l2://" BTW, I have one usb webcam that I move back and forth between these computers.

I can only offer general advice here, but it seems to me that you were having these issues weeks ago...
https://forums.opensuse.org/showthre...4-webcam/page5

With respect to the VLC error, I expect it reported something like "VLC is unable to open the MRL 'file:///dev/video0'. Check the log for details". Did you then check the log?

As per the advice in this thread start vlc in verbose mode (for debugging)

vlc --verbose 2

VLC log...

cat ~/vlclog.txt

That might help yield further useful information, otherwise we can only speculate.

More info:
https://forum.videolan.org/viewtopic.php?t=3092

[Prexy]

Thank you deano_ferrari for trying to help.

You're right. I gave up for awhile after the previous posts for help. That's why I tried a new thread.

The vlc --verbose 2 command

gives me a great deal of output. I can post it but it is dozens and dozens of lines. I have to confess my ignorance. I didn't know where to look for the log referred to in the error message. With your advice, I ran

cat ~/vlclog.txt

but the result was

/vlclog.txt: No such file or directory

I did this, obviously, on the problem computer. I'm going to go boot up the laptop and run these again for comparison purposes.

[Prexy]

Booted up the laptop and opened the webcam. It worked as expected. I ran the two commands and looked for differences from the desktop. There still was no vlclog.txt but scrolling back through the verbose output I found errors in the webcam output.

[00007f9ec8001120] v4l2 demux error: not a video capture device
[00007f9ec8001120] v4l2 demux debug: opening device '/dev/radio0'
[00007f9ec8001120] v4l2 demux error: cannot open device '/dev/radio0': No su
ch file or directory

This error is repeated but refers to "no streaming device." These errors do not appear on the laptop where the webcam is working properly. At first, I thought a solution would be to buy a new webcam. But, why would the results be different? Also, the webcam has a built-in mic which works on the laptop. I presume that mic is the source of the error message about radio.

[deano_ferrari]

What does the following report?

v4l2-ctl --list-devices

[Prexy]

What does the following report?

v4l2-ctl --list-devices

I get this:

v4l2-ctl --list-devices
MyPhone Camera (platform:v4l2loopback-000):
        /dev/video0

Webcam (platform:v4l2loopback-001):
        /dev/video1

USB2.0 PC CAMERA (usb-0000:00:1d.0-1.8):
        /dev/video2
        /dev/video3
        /dev/media0

That is the desktop where it fails. On the laptop, where it works, I get only the part starting with USB2.0. Before I found this webcam in the garage, I tried using an old cellphone as a cam with a couple of different apps and files from the repo. I wonder if there is a conflict from this lingering software. I also tried selecting video0 through video3 specifically instead of letting vlc select what it saw as default. There was no option to select media0. The result was always the same: failure.

[deano_ferrari]

What is reported by the following?

ls -l /dev/video*

[Prexy]

What is reported by the following?

ls -l /dev/video*

crw-rw----+ 1 root video 81, 0 Jan 27 15:57 /dev/video0
crw-rw----+ 1 root video 81, 1 Jan 27 15:57 /dev/video1