Flicker Period?

[bhjelstrom]

Looking for an example utilizing the RPI IPA AGC's SetFlickerPeriod(). Getting pretty bad banding at low exposures which is a regression from the legacy stack.

[davidplowman]

Just out of curiosity, what do you mean by "low exposures"? The legacy stack had no ability to suppress flicker when the exposure time was less than 10ms. Would you be able to report the exposure time and gain you're seeing in both the "good" and "bad" cases? Thanks!

In the meantime I'll look into this problem. The principal issue, I believe, is that libcamera has no controls that plumb into the SetFlickerPeriod() method.

[bhjelstrom]

Hi David, I was most likely mistaken about this being a regression. We are exploring a fundamentally different use case that simply highlights the flicker issue. Our old use-case called for completely black images which made flicker unnoticeable, and our new use-case calls for slightly brighter images. We are definitely always under 10ms. Will play with the frame period in the meantime, but access to SetFlickerPeriod will surely help!
Thanks!

[naushir]

This has now been merged into libcamera. The accompanying change for libcamera-apps to enable flicker control is at #544.

[naushir]

Flicker control is now available with the --flicker-period command line option. Note that you need the very latest libcamera + libcamera-apps top-of-tree builds for this to be available.