Larger campus needs for delivering video content can be more varied than at first appearance.
The instinctive choice is to utilize a category cable solution. While these systems do deliver quality video and a host of other data over a convenient simple topology, there are times when something more is needed.
SDI can provide broadcast quality video suitable for situations where HDMI or Category cable topology limitations are problematic. Often this can be done over existing copper lines or with minimal upgrades to a facility
What is SDI/ HDSDI
SDI stands for Serial Digital Interface. As the name implies this SMPTE 259M standard can transport digital video over coax with multiple channels of PCM audio. HDSDI, the high definition version,(SMPTE 292M) provides 1080p and beyond via single 75 Ohm coax connection.
The standard is used a good deal with the broadcast environments and institutions where synchronization is an absolute need, provides tools to manage distribution and single wire transport is required.
Copper is fairly inexpensive to install and the intermediary connection devices often have a lower cost over time used. Is implementing SD/HDSDI right for you? In order to answer this we need to look at some of the relative advantages and disadvantages.
Advantage SDI
SD/HDSDI has some major advantages over HDMI or the category cable transport topologies.
First and foremost, SDI was designed for use in broadcast and does not have any provisions for DRM (Digital Rights Management) or the dreaded HDCP (High-Bandwidth Digital Content Protection) security. Having no concerns for the verification and calculation of data keys, handshakes, and checksums frees up bandwidth and reduces processing overhead on the chip sets.
One cable carries multiple channels of audio. While HDMI and CAT cable systems can deliver surround sound channels, SDI has sixteen to 32 channels of discrete audio. Having individual channels which are not encoded, or steered provides flexibility consumer based systems cannot.
If you have any experience in editing together multiple clips of video which require accurate synchronization then you know the value of timecode. The timecode is delivered on the same single cable thereby eliminating the need for additional runs. Having TC on one wire insures that incompatible lengths do not skew the timing between content and timecode.
The fact that the signal is a digital serial format also means that it can be adjusted via relatively low cost boosters, repeaters and equalizers. A very handy option to have when needed.
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