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SDI(1) See software-defined infrastructure, Single Document Interface, Strategic Defense Initiative and Switched Digital International.
(2) (Serial Digital Interface) SDI is a unidirectional video interface. Standardized by SMPTE in the late 1980s, SDI has been the primary interface for transmitting uncompressed digital video signals. SDI will eventually be replaced by IP-based NDI, and the many cables used in broadcasting facilities will be replaced with an Ethernet topography. See NDI.
SDI uses a high grade of coaxial cable and a BNC connector with Teflon insulation. It also supports optical fibers with ST, SC and FC connectors. Following are the common formats transmitted over SDI. See ITU-R BT.601, BNC connector, fiber-optic connectors and serial interface.
SD-SDI Aspect Transfer(Standard Definition) Ratio Rate Digitized NTSC (4FSC) 4:3 143 Mbps Digitized PAL (4FSC) 4:3 177 Mbps Component ITU-R BT.601 4:3 270 Mbps Component ITU-R BT.601 16:9 360 Mbps HD-SDI (High Definition) See HD-SDI. Component ITU-R BT.709 16:9 1,485 Mbps Dual-link (two cables) 2,970 Mbps 3G-SDI (3 Gbps) One-cable version of HD-SDI 2,970 Mbps
|Blackmagic SDI Capture Board|
|Two sockets are input, and two are output. At 4:2:2 color sampling, SDI uses one line for in or out. However, HD-SDI at 4:4:4 requires two lines. See chroma subsampling. (Image courtesy of Blackmagic Design Pty. Ltd, www.blackmagicdesign.com)|