v4l2loopback-ctl set-caps hint uses deprecated format

[ntorresalberto]

Overview
Droidcam suggests how to change the format but the message uses an oudated command on v4l2loopback-ctl.

I provide the complete log as well as the final command that fixes it.

LOG

[user@fedora ~]$ droidcam
Fatal: droidcam video device reported pixel format 34524742 (BGR4), expected 32315559 (YU12/I420)
Try 'v4l2loopback-ctl set-caps "video/x-raw, format=I420, width=640, height=480" /dev/video<N>'

[user@fedora ~]$ v4l2loopback-ctl set-caps "video/x-raw, format=I420, width=640, height=480" /dev/video<N>
bash: syntax error near unexpected token `newline'

[user@fedora ~]$ v4l2loopback-ctl set-caps "video/x-raw, format=I420, width=640, height=480" /dev/video
WARNING: 'v4l2loopback-ctl set-caps <caps> <image>' is deprecated!
WARNING: use 'v4l2loopback-ctl set-caps <device> <caps>' instead.
ERROR: GStreamer-style caps are no longer supported!
ERROR: use '<FOURCC>:<width>x<height>[@<fps>] instead
       e.g. 'UYVY:640x480@30/1' or 'RGBA:1024x768'

[user@fedora ~]$ v4l2loopback-ctl set-caps /dev/video "I420:640x480@30/1"
unable to set requested format: Invalid argument

[user@fedora ~]$ v4l2loopback-ctl set-caps /dev/video "I420:640x480"
unable to set requested format: Invalid argument

[user@fedora ~]$ v4l2loopback-ctl set-caps /dev/video "YU12:640x480"

System is running droicam 2.0.0 and Fedora 38 (with v4l2loopback from repos).

In conclusion

• The original command has a <N> that should not be there.
• v4l2loopback-ctl was updated and the command is wrong anyways, droicam should suggest something along the lines of: v4l2loopback-ctl set-caps /dev/video "YU12:640x480"

PS: Thank you for this great app!

[sergiotca]

This!

Your suggestion v4l2loopback-ctl set-caps /dev/video "YU12:640x480" actually fixed the issue I had this morning when updating to 6.3.6 under Fedora

*EDIT: I just realized I need to do this again after every system reboot for droidcam to work.
Any way to make this survive reboot?

[aramg]

• Video devices are usually numbered, /dev/video0, /dev/video1, ..., which is why the <N> is there.
  I have not verified, but I assume the /dev/video you are seeing is a symlink to the default device.

• The set-caps format does need to be updated in the error message

[ntorresalberto]

• Video devices are usually numbered, /dev/video0, /dev/video1, ..., which is why the <N> is there.
  I have not verified, but I assume the /dev/video you are seeing is a symlink to the default device.
• The set-caps format does need to be updated in the error message

I'm not sure why it works but there's no /dev/video there:

$ ls -lha /dev/video* 
crw-rw----+ 1 root video 81, 0 Jun 11 23:11 /dev/video0

I can confirm what @sergiotca says. I also need to run the v4l2loopback-ctl command after restart to fix it (and I'm also on Fedora).

[sergiotca]

Sorry to bump this but I still need to do this every time I reboot for droidcam to work.

Anyone know a way to make this fix permanent?

[aramg]

Will have to carve out some time too look into this in a Fedora dev env.

The only option I see is trying to set keep_format to 1, and see if that makes it survive reboot.
https://github.com/umlaeute/v4l2loopback#attributes

There isn't a module option to set the format at load time (https://github.com/umlaeute/v4l2loopback#options), which is btw the main difference with the version of v4l2loopback that comes with the droidcam client.

[mak448a]

Sorry to bump this but I still need to do this every time I reboot for droidcam to work.

Anyone know a way to make this fix permanent?

Try adding it to bashrc

[mak448a]

Any way to fix the error that happens now with the command v4l2loopback-ctl set-caps /dev/video "YU12:640x480"?
It says this:

VIDIOC_G_FMT: Invalid argument
unable to set requested format: Invalid argument

[aramg]

Try v4l2loopback-ctl get-caps /dev/video, if the caps are already set then you may not be able to change it.
The latest droidcam client release essentially does a set-caps now.

[mak448a]

I just had to update droidcam. Thanks!