Fiber Optic Video Distribution:
Why SDI over fiber?
Latency is one of the prime reasons to use fiber. As the high speed serial signal
enters the converter, that input is used to directly drive a laser circuit. There is no
manipulation or buffering of the signal at all. The only delay is the time it takes the
laser to respond to the input signal, and for the delay in fiber. Fiber delay is typically
around 5 microseconds per kilometer and we don’t have very much. The end to end
delay of this system will likely measure less than 100 microseconds. Far below 1ms.
SDI transmitters use 3 Gbps optics (twice the bandwidth of a DVI link.) 10-bit TMDS
link (DVI) operates at up to 165 MHz and offers 1.65Gbps of bandwidth. This is
enough to operate a digital flat panel display at 1920 x 1080 resolution refreshed at
60 Hz.” A duel link will double this .
Deployment of 3G-SDI links in a network array allows for future integration of higher
resolution displays such as 2k and 4k video systems.
No codec / No IP/No packetizing means no latency nor network collisions/delays
High speed SDI optical network allows Digital video to be pulled down/uploaded
from any station on the network.
SDI was developed for the pro video industry with the goal being performance,
while DVI is a consumer standard designed around content protection.
Many professional routing and switching systems are available for SDI to allow
further control and management features to be integrated in the future.
Uses single BNC cable. Less real estate on a unit and pushed pin, etc are not any
The proposed system combines a
dedicated high speed optical Ethernet
network with a purpose built SDI
broadcast distribution system
Unlike other software approaches
(Video over IP ,PC over IP) this is a
hardware solution that multiplexes
Audio , Video and IP Over Fiber for
exceptional capacity and speed.
Supports 1920 x 1200 video
Can be used together with any other IP
Utilizes the Fiber Optic Links already in
Deltacast 3G-SDI cards are able to output
SDI video at 1920×1200…up to 4k!
Provides real time video and audio with
less than 1ms delay.
Employs Wavelength Division
Multiplexing of Video and ENET(IP) for
Minimize Subsystem Impact
1920 x 1200 video Resolution
Utilize in place Fiber Optic links
Consider Long Term Goals::
– Co-locating all of the display servers/processors
– Move to Larger ,Multiple (5) Display areas (40in)
with attendant Higher resolution
Reduce Display area Footprint (ORP)
To combine many SDI on one fiber ,CWDM multiplexation could be use :
The Thor system uses CWDM filters to control the flow of optical channels.
Two channels are used for IP communication between an SFP based optical switch
and the chassis Enet cards. These two wavelengths are filtered off at the input to the
The remaining wavelengths are combined via a common Optical PLC coupler.
Any optical signal inserted at any Chassis station will be available to all other
stations with the proper receiver card installed.
Optical wavelengths are independent from each other and can be sent to different
places. Each wavelength functions as an independent optical channel and can carry
any type of data.