@@ -102,3 +102,24 @@ register programming sequences shall initialize the :ref:`V4L2_CID_HFLIP
values programmed by the register sequences. The default values of these
controls shall be 0 (disabled). Especially these controls shall not be inverted,
independently of the sensor's mounting rotation.
+
+Embedded data
+-------------
+
+Many sensors, mostly raw sensors, support embedded data which is used to convey
+the sensor configuration for the captured frame back to the host. While CSI-2 is
+the most common data interface used by such sensors, embedded data can be
+available on other interfaces as well.
+
+Such sensors expose two internal sink pads (pads that have both the
+``MEDIA_PAD_FL_SINK <MEDIA-PAD-FL-SINK>`` and ``MEDIA_PAD_FL_INTERNAL
+<MEDIA-PAD-FL-INTERNAL>`` flags set) to model the source of the image and
+embedded data streams. Both of these pads produces a single stream, and the
+sub-device routes those streams to the external (source) pad. If the sub-device
+driver supports disabling embedded data, this can be done by disabling the
+embedded data route via the ``VIDIOC_SUBDEV_S_ROUTING`` IOCTL.
+
+In general, changing the embedded data format from the driver-configured values
+is not supported. The height of the metadata is device-specific and the width
+is that (or less of that) of the image width, as configured on the pixel data
+stream.