Traditionally, most video production houses and broadcasters have transmitted their live video feeds over analogue video links and occasionally over DVB (Digital Video Broadcast) satellite links. Recently there has been a lot of talk of this telco service coming to an end and being replaced by a digital ATM offering.
"This has placed a number of industry players in a quandary as to how to cost-effectively replace these links," says Mark Chertkow, MD of Graphic Image Technologies, a company specialising in video transmission solutions over DVB, IP and GSM.
In the traditional broadcast scenario, broadcasters would compress their signals and transmit them digitally using an end-to-end system. DVB encoders (such as a Scopus E1000) with ATM interfaces at the remote site would transmit over ATM to an IRD (integrated receiver decoder such as an IRD2600) at the receive site, providing the broadcaster with an end-to-end video delivery system over a telco platform. These systems would traditionally operate at bandwidths of 2- 8Mbps, says Chertkow.
Setting up these systems can, however, be very expensive for the smaller production facilities, both operationally and from a capex point of view.
"A number of cost-effective options do, however, exist," says Chertkow. By looking at options for streaming over IP, or using store and forward technologies, broadcasters and production houses can cut costs without necessarily compromising quality.
By implementing an IP streaming solution, Diginet or microwave link, we are able to connect our analogue video and audio input to an MPEG compression device (such as an MGW2000) and stream the video over an IP link. Good quality business TV feeds can be obtained at bit-rates as low 1.5Mbps. By setting up an IP set-top box or PC with a decoder at the broadcaster, we can deliver live video feeds cost-effectively while maintaining video quality.
In addition, in non-real-time environments the same infrastructure can be used to deliver very high quality video files via store and forward technologies. This means the production house records the files in high quality and transfers the file to the broadcaster over the same IP infrastructure used for live streaming.
Where the broadcaster has excess IP capacity, options even exist to broadcast DVB over IP, thus saving on the ATM access costs. By carefully evaluating their video delivery requirements, production houses and broadcasters today do have a number of viable options.
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