(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.)