I\'m using Nitrogen6x board with ov5640 camera(mipi).
The camera is not using standard v4l/v4l, but we can stream video using GStreamer for its driver (mfw_v4l):
Just for reference, this works in OpenCV 3.0:
VideoCapture cap("souphttpsrc location=http://root:admin@192.168.5.123:80/mjpg/video.mjpg ! decodebin ! videoconvert ! appsink")