3G-SDI vs 6G-SDI: What's the difference?

3G-SDI vs 6G-SDI: What's the difference?

As applications such as broadcast, live events and fixed installations demand higher bandwidths (4K, 8K...), SDI standards are also evolving, including HD-SDI, 3G-SDI, 6G-SDI, 12G-SDI. To learn more, check out: SDI, HD-SDI, 3G-SDI, 6G-SDI, 12G-SDI: What are the Differences? This article will briefly introduce what is SDI? 3G-SDI vs 6G-SDI between them difference?


SDI (Serial Digital Interface) is a family of digital video interfaces (SDI, HD-SDI, 3G SDI, 6G SDI and 12G SDI), that was first standardized in 1989 by SMPTE (The Society of Motion Picture and Television Engineers). The standard has been widely adopted by the broadcast industry, and is used for transmission of uncompressed, unencrypted digital video signals in TV studios and facilities. In the live event industry, SDI is also a trusted technology – due to its rugged connector as well as signal distribution lengths.
As the world changes, so has the SDI standard. Additional versions of the SDI standard have been developed to support continuously increased resolutions (HD, UHD, 4K, 8K), higher bitrates and more colors. The latest additions to the SDI family of interfaces made their debut in March 2015, when 6G SDI and 12G SDI standards were published. 12G is now ready for mass market and there are numerous products supporting it.

What Is 3G-SDI?

3G-SDI has been widely used in the radio and TV industry. With the continuous development of the security industry, its advantages, high speed and without digital uncompressed, are gradually found. At present, a large number of 3G-SDI series products have been introduced in the market, including SDI conversion equipment, SDI digital switching matrix equipment and SDI distributor. These devices use 3G signals, and can also be compatible with 1.5G signals for long-distance transmission to meet the diverse needs of users.
3G-SDI digital video optical terminal device with ultra high definition is an upgraded version of the HD-SDI optical terminal device. The signal format is from 19.4Mbps to 2.97Gbps, and the system is accorded with the signal of digital TV formats such as SMPTE424M, SMPTE292M, SMPTE259M, SMPTE297M, SMPTE305M, SMPTE310M, DVB-ASI (EN50083–9) and so on.

What Is 6G-SDI?

6G-SDI: This standard defines a bit-serial data structure, electrical signal and coaxial cable interface for the transport of signals with a total payload of 5.940 Gb/s or 5.940/1.001 Gb/s. This standard also specifies the electrical and physical characteristics of coaxial cables and connectors. This standard defines several mapping modes for the carriage 2160-line and 1080-line image formats and associated ancillary data into a Single-link 6 Gb/s [nominal] SDI bit-serial interface.

3G-SDI vs 6G-SDI: Differences

Although 3G SDI appeared much earlier than 6G SDI, 6G SDI is superior in all aspects and is more suitable for digital video display. 6G-SDI has a higher transmission rate and better clarity than 3G-SDI.
4K content can be distributed via 3G-SDI, but the solution is not as elegant as 6G-SDI. 3G-SDI supports a 1080p signal, so a Quad Link of four separate cables is required to send one 4K signal, which also means the 4K signals requires four inputs on a 4K-capable 3G-SDI video switcher or router. Each cable is responsible for one-fourth of the image, so the cables must be attached in the correct order to recreate the 4K image correctly. While there are other options available on the market, 6G-SDI offers numerous advantages for content creators.


SDI, widely used in SDI encoder, SDI converter and other equipment, has been used in radio and television, security monitoring and other fields. We have witnessed the evolution of video standards from SD-SDI, HD-SDI to Ultra HD standards of 3G-SDI, 6G-SDI, 12G-SDI and 24G-SDI. At the same time, it also promotes a new era of digital video display in the fields of surveillance and broadcasting.
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