SDI is an acronym for Serial Digital Interface. It is a standard for digital audio and video transmission over coaxial cables. The SDI is a professional video connection that is preferred in production environments because of its outstanding properties, such as its length. It has a length range of 300 feet, which makes it suitable for production and outdoor environments. Also, it comes with a BNC cabling, a strong mechanical structure that ensures that the SDI remains connected despite tough turbulence. This helps to avoid disconnection during live stream broadcasts.

History of SDI

The development of the first SDI professional video standard can be dated back to 1989. This was done by the Society of Motion Picture and Television Engineers (SMPTE). After that, some updates have been made.

Standard Definition SDI (SD-SDI): It was first developed in 1989. It transmits video and embedded audio at bit rates ranging from 177 Mbps and 270 Mbps. It is mostly used for 480i and 576i video formats.

High Definition SDI (HD-SDI): It was first developed in 1998. It transmits video and embedded audio at a rate of 1.5Gbps and is mostly applied for 720p and 1080i video formats.

Dual Link HD-SDI: It was first developed in 2002. It transmits video and embedded audio at a combined rate of two 1.5 Gbps, making a total of 3 Gbps. It is mostly applied for 1080p videos.

3 Gbps SDI: It was first developed in 2006. It transmits video and embedded audio at 3 Gbps bit rate. It is mostly used for 1080p videos.

6 Gbps SDI: It was first developed in 2015. It transmits video and embedded audio at 6 Gbps bit rate. It is mostly used for 1080p video formats at 60 frames per second and 2160p video formats at 30 frames per second.

12 Gbps SDI: It was first developed in 2015. It transmits video and embedded audio at a bit rate of 12 Gbps. It is generally used for 2160p video formats at 60 frames per second.

What is DVI?

DVI, digital video interface. With the development of display technology, especially the wide application of digital LCD, DLP and PDP products, the traditional VGA analog signals are not suitable for the development needs. In many applications, they are replaced by DVI digital signals. In the analog display mode, R.G.B signal in the graphics through the D / A converter into an analog signal, after transmission into the display, the processed drive R.G.B gun, displayed on the screen, the entire process is simulated. Unlike DVI digital display, analog RGB signals arrive at the display device (LCD or DLP, PDP, etc.) through A / D processing, converted to digital signals, followed by the digital signal to control the LCD panel to transmit or reflect light or DMD chip reflected light Or reflected by the plasma to achieve the display effect. In this process, there is obviously a process of conversion from digital to analog to digital with large signal loss and problems such as smearing, blur, ghosting and the like. In today’s devices, computer graphics with digital interfaces have become quite common, and even laptops are equipped with DVI interfaces, and most display graphics processors have even digital signal interfaces on them, and the display device is also the more The more equipment comes with a digital signal interface, so the digital → digital application has matured. DVI signal as a new media, its application is more and more widely.

SDI vs DVI

The Serial Digital Interface cable is not present on most consumer-level audio/video equipment. Found mainly on pro-level gear, SDI is based around simple coaxial cable. SDI, terminated with BNC locking connectors, is capable of multichannel audio and high-definition video. SDI is capable of carrying signals longer distances than DVI, up to 100 feet or more, compared to DVI's 75-foot maximum limitation. SDI is capable of being added to analog equipment without adding more chips to the device, tapping into the audio and video processors directly. SDI is a cable that is relatively easy to field-terminate, unlike DVI which requires machine precision.

Connectors

DVI uses a VGA-style connector, utilizing thumb screws to connect the cable to the jack on the device. This creates a reliable connection that will not pull out through shifting of connected equipment. SDI uses a BNC connector, pushing onto the BNC jack and locking with a twist. SDI coaxial cables do, however, run the risk of disengaging from the BNC connectors, since these are often simply crimped into place. DVI cables have molded strain relief on their connectors, decreasing this likelihood. In both cases, under normal use, the connection to the equipment itself is exceedingly robust.

Prevalence

SDI, despite its seemingly superior capabilities, is rarely found on consumer gear. Typically, aftermarket modifications adding SDI to digital equipment is possible at some expense. DVI is far more common on consumer-level gear. However, most consumer electronics made after 2005 probably will not have DVI connectors, but rather HDMI.