Different brightness on NV12 capture from RAW16 capture with same exposure/gain

We have made some tests to verify some ISP functionality.
We came to this conclusion:

Capturing images in NV12 from isp using GStreamer or C++ libArgus gives a much higher brightness than when capturing images with Argus RAW16 format or v4l2. (we divide RAW16 by 256 to get 8bit values.)

RAW16 seems to have much better image-quality. Better black values, etc.

How does this come? What does the ISP do, that it increases brightness so much in a strange way?

Exposure and gain values have been set manually to compare or have been set by AutoExposure in different experiements. When using AutoExposure you can see that the image with NV12 fits better in brightness than the RAW16 format even when they have the same exposure and gain values.

I’d prefer a RAW16 format-like image with correct brightness from AutoExposure. Guess we will stick to RAW16 and increase exposure compensation…

Still I am wondering why und what the ISP makes. Or is it misconfiguration by my side?

Best regards,

NV12 is the output of ISP engine and the result depends on the parameters. Would need to do IQ tuning to get the image fitting your expectation. For IQ tuning, you may contact our camera partners for further information and help.

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