Let’s check if you can have 720p in this mode.
what is the output of:
sudo v4l2-ctl --device /dev/video0 --stream-mmap=4 --stream-count=1 --stream-skip=150 --set-fmt-video=width=1280,height=720,pixelformat=NV12
/dev/video0 or any other /dev/videoX possible.
I looked at the driver and seems only these resolutions are available in all modes:
640x480@60fps
2560x1920@?fps
1920x1080@30fps
2592x1944@15fps
1296x972@45fps (in theory)
Maybe one way to get 720p is to resize the grabbed image (1080p) with gstreamer using hw acceleration.