I have a couple of sample DNGs from the DJI Mavic Air 2 which features a 48mp quad bayer sensor. At 48 megapixels it outputs quad bayer DNG files at ~90mb in size.
Running dng_validate on them does not however reveal them to be a quad bayer sensor:
CFARepeatPatternDim: Rows = 2, Cols = 2
CFAPlaneColor: Red Green Blue
CFALayout: Rectangular (or square) layout
I have also checked other quad bayer sensor cameras capable of saving to DNG and they also report a "normal" bayer 2x2 pattern. So I'm trying to determine if the DNG spec actually has a way of specifying a quad bayer pattern.
If it does, great - but then why are all these quad bayer cameras not doing that?
There is a also the possibility that the sensor/camera internally converts ('remosaics') the quad to the regular 2x2 Bayer pattern before saving to a DNG file which can then be consumed by many existing raw processing SW that doesn't understand anything else but 2x2 Bayer (or X-Trans) as of today. The DNG spec itself of course allows for storing other patterns via the CFARepeatPatternDim tag in theory.