5.2. Design Overview

5.2.1. System Architecture

• Display Device

In SDK, UHD, HD and SD display devices are labeled as DUDx (3840x2160), DHDx (1920x1080) and DSDx (720x576) respectively to indicate the capability of the device.

X is the index number, which starts from 0 to distinguish the display devices.

For example, channel 0 HD device is labeled as DHD0, and channel 1 UHD display device is labeled as DUD1. UHD, HD and SD display devices can be referred to as UD, HD and SD devices respectively.

CV181x has a high definition display device DHD0

• Video Layer

For the corresponding video layer fixed on each display device, the SDK also adopts the way of corresponding display device, marked by VUDx, VHDx and VSDx.

The processor supports display device, video layer and graphics layer. Please refer to table 5.1.

Refer to Table 5.2 for functional comparison of processor devices.

The function comparison of video layer is shown in table 5.3.

The maximum timing supported by the video output interface on the device is shown in table 5.4.

The actual display resolution of video layer and display device depends on the specific output interface.

Table 5.1 supports display device, video layer and graphics layer

Processor	Subitem	HD display device DHD0
CV183x	Name	Video layer VHD0	Graphic layer G0
	Description	Supports a maximum of 1 screen
	Output interface	BT.112 0/BT.656, MIPI Tx, LVDS, I80
CV182x/CV181x	Name	video layer VHD0	Graphic layer G0
	Description	Supports a maximum of 1 screen
	Output interface	BT.112 0/BT.656, MIPI Tx, LVDS, I80, RGB

Table 5.2 display device functions

Processor		Maximum output time sequence	Output interface	Overlay display
CV183x	DH D0	1080p@60	BT0112 0/BT.656/MIPI Tx/LCD	Not support
CV182xCV181x	DH D0	1080p@60 720p@60	BT0112 0/BT.656/MIPI Tx/LVDS/RGB	Not support

Table 5.3 video layer functions

Processor	Dynamic binding capability	Zoom capability	Number of channels supported		CSC
			SINGLE mode	MULTI mode
CV183x	Not support	Not support	1	1	support
CV182x CV181x	Not support	Not support	1	1	support

Table 5.4 the maximum output timing of the device interface

Processor		Maximum output time sequence
	MIPI Tx	1080P@60
	BT.1120	1080P@60
	BT.656	1080P@60
	LCD	720P@60
CV182x CV181x	MIPI Tx	720P@60
	BT.1120	720P@60
	BT.656	M720P@60
	LCD	M720P@60

• Channel

The SDK attributes the channel to the video layer management.

A video layer can display multiple videos.

Each video display area is called a channel, and the video is restricted within the channel and the channel is restricted within the video layer.

For a video layer, the channels above are independent.

At the same time, the channels on different video layers are also independent.

• Resolution

There are two main concepts of resolution:

Device resolution is determined by device timing and determines the number of effective pixels output by the device.

Display resolution refers to the effective display area on the display device, which is determined by the stDispRect member in the video layer properties.

The display resolution must be less than or equal to the device resolution.

• Graphic Layer Binding

Graphics layer binding means that the processor supports binding specific graphics layer to video layer.

CV181x supports one graphics layer (G0 is bound to DHD0, that is, G0 can only overlay VHD0.

• Rotation

VO supports rotation of input images.

You can also do rotation first, and do subsequent processing in the access channel.

Usually, it is applied to some vertical screens, and the roatation is set to 90 or 270 degrees to reach full screen and maintain image scale.

• Input and Output Data Formats

The input data formats supported by the VO modules in processor are shown in table 5.5 below.

The PIXEL FORMAT and VIDEO FORMAT in the table respectively list the input pixel format and video format supported by the processor.

The data format in the table can refer to the chapter “2 system control”.

Table 5.5 input data formats supported by processor

Processor		Input
CV183x	PIXEL FORMAT	YUV PLANAR 444 YUV PLANAR 422 YUV PLANAR 420 YUV 400 RGB PLANAR 888 BGR PLANAR 888 RGB Packed 888 BGR Packed 888
	VIDEO FORMAT	LINEAR
CV182xCV181x	PIXEL FORMAT	YUV PLANAR 444 YUV PLANAR 422 YUV PLANAR 420 YUV 400 NV12 NV21 NV16 NV61 YUYV YVYU UYVY VYUY RGB PLANAR 888 BGR PLANAR 888 RGB Packed 888 BGR Packed 888
	VIDEO FORMAT	LINEAR