Problems when using 2 Webcams on Mint 20.3 with OBS 28

[crapman]

I used to work with 2 USB webcams simultaneously (1xLogitech C922 Pro (primary cam) and 1x Logitech QuickCam Pro 5000 as secondary cam) on my old Mint 19.3 Mate platform with OBS 27.2.4 and I never had any problem with it. On my Mint 20.3 (Cinnamon) I managed to establish the same arrangement with OBS 28.0.1 but sadly after a removal of the QuickCam Pro 5000 (needed somewhere else) and a reboot of the PC the webcams in the scenes where either gone or swapped.

Without the secondary QuickCam Pro 5000 I found this device mapping under /dev/v4l/by-id :
usb-046d_C922_Pro_Stream_Webcam_5CB212DF-video-index0 (mapped to video 0)
usb-046d_C922_Pro_Stream_Webcam_5CB212DF-video-index1 (mapped to video 1)

After I plugged in the QuickCam Pro 5000 and rebooted the PC I got his:
usb-046d_08ce_3C9C41A2-video-index0 (mapped to video0)
usb-046d_08ce_3C9C41A2-video-index1 (is mapped to video1)
usb-046d_C922_Pro_Stream_Webcam_5CB212DF-video-index0 (mapped to video2)
usb-046d_C922_Pro_Stream_Webcam_5CB212DF-video-index1 (is mapped to video3)

That means that the video0/1 – mapping of my primary webcam C922 was shifted to video2/3.
Then I checked the terminal output of OBS and found, that OBS seems to select the webcam by using the video-(n) device.
Does this explain my problem?

Questions:
1. Is OBS ignoring the hardware behind the video-(n) device?
2. If yes, can this be changed (of course only if this makes sense)?

I was assuming since OBS 28 that the hardware behind a video(n) device must be known to OBS in order to support special settings/features of a certain camera type. It seems that this is not the case.

Is there an easy way to set a primary webcam as "default webcam" (video0) in Mint 20.3? Are there other solutions? Is this possibly a bug in OBS?

Best regards
Crapman

 

[Tuna]

Check https://github.com/obsproject/obs-studio/pull/6493

Alternatively could add some udev rules to ensure cameras are mapped to a static order.

 

[crapman]

Thanks for your quick reply!
As I understand, I just have to wait until the "OBS-solution" is offered as an update in the ppa, correct?
I would prefer udev rules because it solves the problem also for other apps.
Would this be a solution?: https://www.djsadhu.com/software/li...tting-mixed-up-after-reboot-using-udev-rules/
I am asking because I read somewhere, that OBS doesn't accept other symlinks than "videox".
If this is true, I wouldn't know how establish udev rules, or shall I use higher index numbers like video5/6 for the primary cam and video7/8 for the secondary cam?
Best regards
Crapman