I am comparing the output of the raw data captured through v4l2 on the Xavier NX and Nano platforms, and found an unexpected difference.
I configure the camera to create a very bright image (to better see the data), and using the command
v4l2-ctl --stream-mmap --stream-count=1 --stream-to=raw.dat
I get the following output on the Nano (seen in a hex editor):
FF 0F FF 0F …
This is consistent with the RG12 pixel format, that v4l2 declares to deliver when asking for formats. The information is in the 12 least significant bits.
However, when doing exactly the same test on a Xavier NX (same camera, same driver software, same device tree modifications), I get the following output:
FF FF FF FF …
When interpreting that image data in further processing, it becomes clear that it is in fact not RG12, but the most significant 12 bits contain the information from the camera sensor (which would be the RG16 format, if I am not mistaken).
Is this a known difference in behavior between the Nano and the NX, or is there some kind of configuration that I might have changed unknowingly that can cause this change in the data?