[BUG] preserve_ar unintended zoom/crop with IMX900 Framos GO Module

[kovin-md]

Describe the bug
When preserve_ar is set to True, image is SUPER zoomed in. When preserve_ar is set to False, image is as expected.

To Reproduce

• Follow Framos instructions for IMX900 driver install
• Follow Framos instructions for Framos Libcamera install.
• sudo apt install python3-picamera2 python3-opencv
• Run the attached imx900_test.py script and change the flags to see the difference/bug.

imx900_test.py

Expected behaviour
When preserve_ar is set to True, image will be SUPER zoomed in, and frame rate will be close to what is expected (higher, close to the hardware limit). When preserve_ar is set to False, image will look normal and frame rate will be alot lower.

This behavior tracks for all resolutions and camera configurations I've tried. Also for both preview_configuration and video_configuration.

Console Output, Screenshots
see test_false.jpg (1st picture) and test_true.jpg (2nd picture) - these pictures were taken with the camera pointing at the blinds by my window. Note just how mch more zoomed in test_true.jpg is. I was holding the camera with my hand during both pictures, so they are not pointing at the EXACT same spot in both pictures.

Hardware :
I'm using a Pi Compute Module 5, with the official Compute IO board, and using an IMX900 Framos GO module.

This is the version of bookworm on the module:
https://downloads.raspberrypi.com/raspios_arm64/images/raspios_arm64-2024-11-19/2024-11-19-raspios-bookworm-arm64.img.xz

PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
NAME="Debian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
VERSION_CODENAME=bookworm
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

Additional context
None at this time.

[davidplowman]

Hi, and thanks for the report.

Unfortunately we can only provide general help when people are using 3rd party cameras and 3rd party versions of libcamera, as we have no idea what may be behaving differently. Also it's not entirely clear to me where you are using perserve_ar. It's usually helpful to post a simple rpicam-apps command, or a really short Python script, that demonstrates the problem, although that may be of limited use if we can't use it with an official camera and the official software.

In this case probably the first thing to do would be to post the console log for the working and non-working case. That way we can check that it's not choosing a different camera mode. That's a common problem, though in this case I suspect it may not be the explanation as the zoom effect is so extreme.

There was a period many months ago when the image crop logic was broken and caused an effect like this, so this feels a bit more likely. Obviously we fixed it ages ago, but I wonder if this 3rd party libcamera is not fully up to date?

We do try hard to encourage third party vendors to upstream their camera drivers and contribute their work to the wider Raspberry Pi camera ecosystem as it benefits everyone, so I don't know if they could be persuaded to follow this direction?