2.14.4. Metadata Layouts

The metadata layout control specifies the on-bus layout of the metadata on pads with a generic metadata mbus code independently of the bit depth.

2.14.4.1. MIPI CCS Embedded Data Layout (V4L2_METADATA_LAYOUT_CCS)

MIPI CCS defines a metadata layout for sensor embedded data, identified by V4L2_CID_METADATA_LAYOUT control value V4L2_METADATA_LAYOUT_CCS, which is used to store the register configuration used for capturing a given frame. The layout itself is defined in the CCS specification.

The CCS embedded data format (code 0xa) definition includes three levels:

  1. Padding within CSI-2 bus Data Unit as documented in the MIPI CCS specification.

  2. The tagged data format as documented in the MIPI CCS specification.

  3. Register addresses and register documentation as documented in the MIPI CCS specification.

The V4L2_METADATA_LAYOUT_CCS metadata layout value shall be used only by devices that fulfill all three levels above.

This metadata layout code is only used for “2-byte simplified tagged data format” (code 0xa) but their use may be extended further in the future, to cover other CCS embedded data format codes.

Also see CCS driver documentation.

2.14.4.2. Omnivision OV2740 Embedded Data Layout (V4L2_METADATA_LAYOUT_OV2740)

The Omnivision OV2740 camera sensor produces the following embedded data layout, indicated by V4L2_METADATA_LAYOUT_CCS metadata layout. The format conforms to CCS embedded data layout up to level 1.

Omnivision OV2740 Embedded Data Layout. Octets at indices marked reserved or unused have been omitted from the table. The values are big endian byte order.

Offset

Size in bits (active bits if not the same as size)

Content description

4

16 (10--0)

Analogue gain

6

16

Coarse integration time

10

8

Dpc correction threshold

15

16

Output image width

17

16

Output image height

23

8

MIPI header revision number (2)

31

8

Vertical (bit 1) and horizontal flip (bit 0)

32

8

Frame duration A

33

8

Frame duration B

34

8

Context count (2)

35

8

Context select

54

8

Data pedestal bits 9--2

63

8

Frame average bits 9--2

64

16

Digital gain red

66

16

Digital gain greenr

68

16

Digital gain blue

70

16

Digital gain greenb

89

8

Frame counter (starts at 1, wraps to 0 after 255)