HDMI Port vs SDI Port?What is the difference?

HDMI Port vs SDI Port

We often use SDI ports and HDMI ports in our daily life. We are often familiar with HDMI port, but not familiar enough with SDI port. To understand the difference between the two, you need to have a basic understanding of the SDI port and the HDMI port.

SDI Port

SDI port is a "digital component serial interface". SDI port is an acronym for digital component serial interface (serial digital interface).

The SDI interface is a "digital component serial interface", while the HD-SDI interface is a broadcast-level high-definition digital input and output port, where HD stands for high-definition signal. Since the SDI interface cannot directly transmit compressed digital signals, the compressed signals recorded by digital video recorders, hard disks, and other devices must be decompressed and output through the SDI port to enter the SDI system.

HD-SDI is widely used in non-editing post-production, broadcast stations, etc. It is based on SMPTE292M, which is an interface specification for transmission at 1.485Gb/s or 1.485/1.001Gb/s signaling rates. The specification specifies the data format, channel encoding method, signal specifications for coaxial cable interfaces, connector and cable types, and fiber optic interfaces. The HD-SDI interface uses a coaxial cable, while the BNC interface is used as the cable standard. The effective distance is 100M.

The SDI serial port is an interface that sequentially transmits each bit of the data word and the corresponding data through a single channel. Because the data rate of the serial digital signal is very high, it must be processed before transmission, and it belongs to the digital baseband signal. The SMPTE organization officially released 6G-SDI and 12G-SDI of the serial data interface in 2015. 6G-SDI is oriented to 2160p 30 applications, corresponding to 30 frames per second refresh. And 12G-SDI is oriented to 2160p 60 (commonly known as true 4K) applications, corresponding to the refresh of 60 frames per second.

12G-SDI is for 2160p60 (commonly known as true 4K) applications, bai12G-SDI can integrate 4 lines for transmitting 3G-SDI signals into one, and directly transmit 4K audio and video. Corresponding to 60 frames per second refresh, with 12G-SDI, one cable can handle 4K transmission. In this way, fewer cables are needed, the system is simpler, and the image quality is more guaranteed. Moreover, 12G is backward compatible with 3G/HD/SD, so it is not a problem to access existing systems such as high-definition switchers.

HDMI Port

The full name of HDMI (High Definition Multimedia Interface) is a digital video/audio interface technology. It is a dedicated digital interface suitable for image transmission. It can transmit audio and video signals at the same time. The maximum data transmission speed is 48Gbps, and there is no need for digital/analog or analog/digital conversion before signal transmission.

In simple terms, HDMI is a high-definition video interface, which is more common in mainstream laptops, LCD TVs, graphics cards, and motherboards. The HDMI interface can support 4K, 8K, and 10K full HD format video output. It is currently the most popular high-definition interface, which is unmatched by ordinary VGA display interfaces. Just like telephone line broadband and fiber optics, the ability to transmit data is very different.

Advantages Of The SDI Port Compared To The HDMI Port

SDI is more stable than HDMI transmission

Select the standard transmission method (SDI signal) for the radio and television industry. The self-locking buckle design of the SDI interface is more stable and reliable, not easy to fall off, and will not cause signal interruption due to human factors, which is very important for live broadcasting activities.

SDI has a longer transmission distance than HDMI

A serial interface refers to the sequential transmission of bit-by-bit data. It is characterized by simple communication lines. As long as a pair of transmission lines can realize two-way communication, it is especially suitable for long-distance communication. Theoretically speaking, the transmission distance of SDI can reach 100m, while the transmission distance of HDMI is usually within 30m.

SDI is cheaper than HDMI

SDI costs less than HDMI! Therefore, from the perspective of the particularity of live broadcasting, using the SDI interface is still more stable and reliable.