Introduction to Video Output Interfaces: CVBS, VGA, HDMI, TVI, AHD and More-Knowledge Encyclopedia-Shenzhen Kai Mo Rui Electronic Technology Co. LTD

Introduction to Video Output Interfaces: CVBS, VGA, HDMI, TVI, AHD and More

Source：Shenzhen Kai Mo Rui Electronic Technology Co. LTD2026-06-17

I. Overview of Various Video Interfaces

There is a wide variety of video output interfaces on the market. This document systematically sorts out mainstream types and their characteristics as follows:

1. CVBS

CVBS stands for Composite Video Broadcast Signal. As the most classic analog video interface, it was initially applied in radio and television, and later widely adopted for camera signal output.

CVBS delivers interlaced analog video signals with two standard resolutions:

PAL system: 720×576
NTSC system: 720×480
Classified as a standard-definition analog interface, CVBS is gradually phased out and replaced by digital and high-definition video interfaces nowadays.

2. VGA

VGA is the abbreviation for Video Graphics Array, a traditional analog video output interface commonly used for computers. Its mainstream supported resolutions include 1024×768, 1280×1024 and 1600×1200.

Many industrial cameras are equipped with VGA outputs for direct connection to LCD monitors for real-time preview.

For digitized VGA signals, the maximum clock frequency is generally limited to 162 MHz, with a maximum video data rate no higher than 3.7 Gbps.

3. DVI

DVI stands for Digital Visual Interface, another prevalent video output interface for PCs featuring fully digital signal transmission.

Unlike VGA which undergoes DA conversion at the graphics card and subsequent AD conversion inside monitors leading to signal attenuation, DVI preserves intact digital data without quality loss during transmission.

It has gained growing popularity in the computer industry, and some industrial cameras integrate DVI ports for direct monitor connection.

The maximum clock frequency for single-link DVI is 165 MHz, with a maximum image data rate capped at 3.7 Gbps.

4. HDMI

HDMI is short for High Definition Multimedia Interface, a digital high-definition multimedia interface.

Originally deployed in consumer electronics including set-top boxes, media players, televisions and camcorders, HDMI gains extensive popularity for its native DVI compatibility and embedded audio transmission capability. Benefiting from compact connector size, HDMI has become a mainstream output option for industrial cameras.

HDMI 1.2: Maximum video bandwidth of 3.96 Gbps, widely applied in industrial camera products
Consumer-grade HDMI 2.0: Maximum video bandwidth up to 14.4 Gbps, increasingly adopted by high-speed industrial cameras for image output
A notable drawback of HDMI is poor connector locking stability, prone to loose contact and signal interruption when the camera requires frequent movement.

5. SDI

SDI (Serial Digital Interface) is a broadcast-grade high-definition digital I/O interface, standard for professional broadcast cameras, with a maximum transmission rate of 2.97 Gbps.

It utilizes the same BNC physical connector as CVBS, transmitting signals over a single coaxial cable. Featuring convenient wiring and a maximum transmission distance up to 300 meters, SDI was highly favored in traditional radio, television and video surveillance industries.

6. Camera Link

The Camera Link specification standardizes the interface between digital cameras and frame grabbers, with unified definitions for physical connectors and cables. It contains three basic configurations: Base, Medium and Full.

Camera Link Base: 4 data channels
Camera Link Medium: 8 data channels
Camera Link Full: 12 data channels
With a maximum clock frequency of 85 MHz:
Base effective bandwidth: 2 Gbps
Medium effective bandwidth: 4 Gbps
Full effective bandwidth: 5.3 Gbps
A newer variant, Camera Link Full+, has been released, supporting 80 MHz clock, 80-bit data transmission and a peak bandwidth of 6.4 Gbps.

7. HS-LINK

HS-LINK, also named Camera Link-HS, is led and defined by DALSA for ultra-high-speed transmission. Its single-cable bandwidth is four times that of standard Camera Link while maintaining protocol compatibility, delivering a maximum throughput of 12 Gbps.

8. CoaXPress

CoaXPress enables cameras to transmit data to host devices via individual coaxial cables, supporting a single-line rate up to 6.25 Gbit/s; four cables can aggregate a total bandwidth of 25 Gbit/s.

Leveraging mature coaxial cabling infrastructure, CoaXPress is highly suitable for machine vision, medical imaging and security surveillance markets that widely deploy coaxial wiring.

9. High-Definition Analog Interfaces: HDCVI, HDTVI, AHD

HDCVI, HDTVI and AHD represent three dominant high-definition analog transmission solutions. All three transmit progressive-scan high-definition video over conventional analog coaxial cables.

HDCVI (High Definition Composite Video Interface)
Independently developed and released by Dahua Technology at the end of 2012.
HDTVI (High Definition Transport Video Interface)
Developed by Silicon Valley-based Techpoint Inc., and heavily promoted by Hikvision.
AHD (Analog High Definition)
An analog high-definition solution launched by South Korea’s Nextchip.