ScalerCrop controls

[valdemaria]

HI,

I'm working with libcamera and gstreamer on a RPI4. I use gstlibcamera like this : libcamerasrc ! video/x-raw,width=2048,height=1536,framerate=30/1,format=YUY2,interlace-mode=(string)progressive,colorimetry=(string)bt709

I use this resolution to be in 2x2 binned mode.

I can change dynamically differents controls like Brightness, Contrast, AeEnable etc ...

But when I try to change the ScalerCrop, it doesn't work all the time. I send my rectangle correctly to libcamera. Is there a specific timing to send this ? Is the way to send the scalercrop correct ?

I have implemented a function in gstlibcamera to send controls, and it works perfectly for all the other controls.

default scalercrop value : 2 0, 4052, 3040

try to set scalercrop value to : 1521, 1140, 1013, 760

Thanks for your help ! :)

[kbingham]

Hi @valdemaria, as this is on a Raspberry Pi 4 - could you ask this to RPi4 developers please? https://github.com/raspberrypi/libcamera/issues perhaps - or the raspberry pi forums.

This is just my 'personal development repository'.

Though it would be interesting if you could share a patch for your implementation of the ScalerCrop control to gstlibcamera - it could be something we could integrate into libcamera to support this for others.

[valdemaria]

Thanks for your response.

Do you know if there is a way to debug the controls to see where the problem come from ?

If you want it I can send you my gstlibcamera, maybe you could find a problem, or it could be a good patch. There is only functions to get and set controls.

[kbingham]

Sending the patch would be good - at least I can check if it has any obvious issues. The best option is to send it to the libcamera development mailing list where all of the developers can help in the review process.

https://libcamera.org/contributing.html has the information about submitting to the libcamera mailing list which is [email protected].

If you want to see all of the internal libcamera debug you can run your application/command with the following environment variable set:

LIBCAMERA_LOG_LEVELS=*:0

That will show you far more information of what is happening inside - and if you want to further debug, you can self build libcamera and add further debug to the raspberry pi pipeline handler where the controls are being processed.

You mentioned this is through gstreamer - do you have an example application that is using the control? Your issue doesn't actually state what problem you are seeing. Are the scaler crop controls being ignored completely? Not applied smoothly? Something else?

[kbingham]

haha - of course you are already self-building libcamera as you're updating gstlibcamerasrc ;-)

[valdemaria]

First, I made my pimped gstlibcamera from a v0.0.3 ( higher doesn't work on my rpi, I didn't try to find out why). I join it here, if you think that it could be helpful. I have translated the meson build into makefile, to build gstlibcamera on my project.

I want to make a digital zoom, so I want to crop the good area on my sensor to do it. When I send the control from my gstreamer app to libcamera, most often nothing appears. But sometimes it works, particularly when I send many times the same control. I would like to use this way of cropping instead of videocrop from gstreamer, to avoid issues due to the pixel-aspect-ratio differences.

My pipeline is, globally : libcamerasrc ! video/x-raw, 2048*1536 (to use 2x2 binned mode) ! videoscale ! video/x-raw [1920,1280,640] * [1080,720,360] ! v4l2h264enc ! h264pay ! udpsink.
Currently I use libcamera ! video/x-raw .. ! videocrop ! videoscale ... to make my digital zoom.

Gstreamer1.0_Libcamera.zip