I was going through the code and noticed this part with comment :
selectSensorConfig(0 /* What ever 0 means */);
That is actually binning mode, as per documentation:
Just to note this is for high quality camera, different modes are for different cameras.
Also interesting thing is that zero is "Automatic" but explenation of that part is missing from documentation except this note for all cameras:
Anything output res below 1296 x 976 will use the 2 x 2 binned mode.
If automatic works then setting resolution to half should activate binning automatically, but I am not sure how to test that. Maybe by picturing fixed long distance target(lamp) with different resolutions but same exposure?
EDIT: i just tried reducing resolution, unfortunately it is only crop in current implementation of driver, but with resolution of 2028x1520, download time is 0.5 seconds.
Also I am unable to build and test this mode by changing modes "selectSensorConfig" could someone try to change that and try?