Closed LaurentDelaon closed 6 months ago
umlaeute
commented
6 months ago the loopback camera is not a USB-device. it doesn't attempt to be one.
also, if your application requires a metadata device, then i think it is broken.
i'm closing this as "out-of-scope" resp "won't fix". sorry
LaurentDelaon
commented
6 months ago Hi Umlaeute
As I write is it perfectly work when I connect the application to video0 directly
but don't if I connect on video4 which is a copy of video0 thru v4l2loopback+ffmpeg
ffmpeg -f video4linux2 -i /dev/video0 -codec copy -f v4l2 /dev/video4
So how I can obtain via v4l2loopback the device video1 which isn't 'videocapture' ?
umlaeute
commented
6 months ago as i said, you cannot.
your assumption is, that your application works only with /dev/video0 because there is an accompanying /dev/video1 metadata device.
if this assumption is correct, then i believe the application is broken (because there is no valid reason why there has to be a metadata device at all. i have seen plenty of real hardware capture devices that do not have a metadata device).
in this case, i'm closing this bug-report as "out-of-scope".
if your assumption is wrong, then there is no reason to duplicate the metadata device, and the problem is something else. in this case i'm closing this bug-report as "off-topic" (because then you should start a new bug report, that describes the actual problem)
umlaeute
commented
6 months ago totally off-topic (and unrelated to your problem), but could you please explain why you chose to ignore the template-text of the bug-report? i try to get information about the environment early, because it is usually important.
i'm not asking you to provide this information right now, but wonder why you did not provide it in the first place. i am asking because you are not alone, so i would like to improve my communication in this regard (to keep frustration levels low)
LaurentDelaon
commented
6 months ago I am not english well readers speaker. I haven't clearly understand pre writing. Suggest simpler way : Put in terminal commands and send : sudo dmesg | grep -i v4l2loopback....
sudo dmesg | grep -i v4l2loopback
[sudo] Mot de passe de laurent :
[ 2444.843240] v4l2loopback: loading out-of-tree module taints kernel.
[ 2444.843337] v4l2loopback: module verification failed: signature and/or required key missing - tainting kernel
[ 2444.844988] v4l2loopback driver version 0.12.7 (0.12.7-412-g850a2e3) loaded
[ 8244.940513] v4l2loopback driver version 0.12.7 (0.12.7-412-g850a2e3) loaded
laurent@laurent-NL40-50GU:~/programme/lazarus/pblireUsbCamFfmpeg$ uname -a
Linux laurent-NL40-50GU 5.4.0-150-generic #167~18.04.1-Ubuntu SMP Wed May 24 00:51:42 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
laurent@laurent-NL40-50GU:~/programme/lazarus/pblireUsbCamFfmpeg$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.6 LTS
Release: 18.04
Codename: bionic
Hi everybody,
I want to create and use multiple duplicate usb-camera. This hardware is on device0 ans device1 who desn't have "Video Capture" property. Look at this link : https://bugzilla.kernel.org/show_bug.cgi?id=199575
Reason todo that is that you cannot have multiple access on hardware device0 but possible with duplicate hardware. I have a usb webcam on which define two devices : device0 and device1. I do that and test read video4 and video 6 with vlc , it's works:
Can also use for test :
ffplay /dev/video4My problem come with an application who is perfectly working on video0 (and usage of video1) but unable with video4 because ,according to me, it's can't found the equivalent duplicate of video1... say video5. How can I solve this issue ? possible to do this (simultaneous?) : video0 copyto video4 video1metadata copyto video5metadata ?
[Here I put a code sample under Lazarus : https://forum.lazarus.freepascal.org/index.php/topic,66702.0.html of application sample can read video0 directly but not is duplicate ffmpeg video4]
Thanks to help me on this. Regards. Laurent.