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Is it possible to debug the camera setup ?

Posted: 19 Dec 2018 17:08
by simozz
Hi all,

I am using a IR camera which communicates through UVC on Linux and I am experiencing problems on a ARM embedded board with a C program using V4L2 API.
However, if I open the camera with VLC on my desktop computer on a Debian distribution, I can open it successfully and I can see the frames.

In order to understand what could be wrong in my C program, I would like to debug vlc information in such a way to know what ioctls are being used to setup the camera.
Is there a way to obtain this information with VLC ?

The only information I can retrieve from VLC is from codec information window (pixel format used, resolution and fps) and from v4l2-ctl, which is the following:

Code: Select all

ioctl: VIDIOC_ENUM_FMT Index : 0 Type : Video Capture Pixel Format: 'UYVY' Name : UYVY 4:2:2 Size: Discrete 160x120 Interval: Discrete 0.111s (9.000 fps) Index : 1 Type : Video Capture Pixel Format: 'Y16 ' Name : 16-bit Greyscale Size: Discrete 160x120 Interval: Discrete 0.111s (9.000 fps) Size: Discrete 160x122 Interval: Discrete 0.111s (9.000 fps) Index : 2 Type : Video Capture Pixel Format: 'GREY' Name : 8-bit Greyscale Size: Discrete 160x120 Interval: Discrete 0.111s (9.000 fps) Index : 3 Type : Video Capture Pixel Format: 'RGBP' Name : 16-bit RGB 5-6-5 Size: Discrete 160x120 Interval: Discrete 0.111s (9.000 fps) Index : 4 Type : Video Capture Pixel Format: 'BGR3' Name : 24-bit BGR 8-8-8 Size: Discrete 160x120 Interval: Discrete 0.111s (9.000 fps)
Thank you in advance.
s.

Re: Is it possible to debug the camera setup ?

Posted: 19 Dec 2018 20:42
by RĂ©mi Denis-Courmont
Well, VLC is open source, so yes you can debug it...

Re: Is it possible to debug the camera setup ?

Posted: 19 Dec 2018 20:50
by simozz
VLC is open source, so yes you can debug it...
This is something that doesn't need explanations..
I was wondering if there exists some already implemented options that makes the debug (of v4l2 API ioctls) available without the need of recompiling the software.
That's it.

Regards,
s.