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NAB special: Internet broadcasting
Getting started in Internet broadcasting roadcasting on the Internet is here now and is getting bigger by the day. The technology has created opportunities for anyone to reach millions around the world, whether by staging live webcasts of rock concerts, distributing corporate videos to the investment community or merely enlivening static websites with video clips. Conventional broadcasters are on notice: they must join the Internet bandwagon or get left behind.
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So how easy is it for potential and conventional broadcasters for that matter - to set up shop in cyberspace? The answer: it has never been easier. Within the last few years broadcasting equipment manufacturers have introduced a raft of editing, coding and content management tools to streamline the tasks of re-packaging or repurposing broadcast content for streaming delivery via the Internet. And a number of specialised streaming media server companies have emerged to handle the business of broadcasting to the Internet. These companies can accept live video satellite and landline feeds or tapes, encode the broadcast material in real-time into a compressed video format suitable for the Internet, and stream it to end users via the global Internet or a corporate Intranet. The emergence of a video streaming industry means that if they want, broadcasters can choose to focus on their primary interest of developing programme content. But not surprisingly, many
Even
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of the larger organisations have made it their business to deploy Internet broadcasting technology. Here we take a look at the various steps in the Internet broadcasting chain, using some leading vendors for examples of the products used in the studio, through the encoding and video streaming process, to its delivery via an Internet browser. In the studio
Ideally, Internet broadcasting should integrate seamlessly with the broadcaster’s production set-up. This goal has been greatly assisted by the move from dedicated analogue hardware systems to a digital production set-up in which editors, sitting at PC workstations, can access video material stored on networked video servers. For example, CNN, the 24-hour video news network, made a strategic decision to move all its news operations to a compressed digital production environment based on the MPEG-2 video broadcast standard. Grass Valley, a leading US manufacturer of broadcast equipment, services this market with its Profile XP video server solution. In operation, editors can view incoming news, work on the video files and return the edited version to the server. They can also call up archive material held on the network using Grass Valley’s ContentShare media asset management software. To re-format video content for the Internet, they use WebAble, a Grass Valley software package
concentrate
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content production need to understand the basics of Internet broadcasting. Here Kevin Smith looks at the processes and technologies needed in the field, in the studio, and in the delivery networks page twenty eight
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that is designed to work with ContentShare. With WebAble, they can access and view media assets, then transfer them to a web server in a simple drag-anddrop operation. And parameters for video streaming such as bit rates and frame rates can be setup using an on-screen template. WebAble also lets users embed video clips or streaming video into conventional web pages together with textual information, interactive elements and graphic overlays. A video clip then becomes just another file in a conventional HTML page and can be composed using conventional web-editing tools such as Macromedia’s DreamWeaver or Microsoft’s Front page. In the field
When Madonna strutted her stuff for an international pop event, a few thousand fans crammed into Brixton Academy in London to see her in person, but an estimated nine million viewers watched her live webcast, or viewed the web archive, later. NTL Broadcast provided outside broadcast facilities for the gig. With a 46-year history in conventional broadcasting, NTL sees live Internet broadcasting as a major business opportunity. In September 2001, it launched a real-time video streaming service aimed at taking the fuss out of live video broadcasting via the Internet. According to Tony Orwin, sector manager of business and events television at NTL, live events of this sort are one of the fastest growing sectors of the Internet broadcasting business. This market also includes corporate broadcasts, as more and more companies use the Internet to broadcast annual meetings, issue video releases or make corporate broadcasts via their intranet. NTL provides TV production equipment and crews, satellite uplinks connecting to its main Cable & Satellite International
satellite teleport at Winchester, streaming servers and archiving services. “We are a professional broadcasting service that just happens to use the Internet,” says Orwin. Although the end result today is a small, low quality image on a PC screen, it is nonetheless important to produce master content of the highest quality. Since video compression involves a loss of quality, archived source material needs to be stored in the best form possible. Streaming media services
Internet broadcasting is about providing individual choice on demand. For a popular website featuring streaming video, aggregate demand and hence bandwidth can add up quickly, and the infrastructure to support this can be costly. So there is a strong economic case for broadcasters to hand this function over to specialist media streaming companies. “Video streaming,” says Peter Millar Hagerty, head of technology for Virtue Broadcasting, “ is a very specialised market requiring heavy capital investment in transcoding, media streaming servers and broadband networks.” The bigger the event, the greater the capacity that will be needed. To that end, Virtue Broadcasting owns and operates a high capacity Pan-European network that can be configured from a single control centre just like a local area network. "To match capacity to demand wherever it arises, we can escalate streaming video resources in a matter of minutes,” explains Millar Hagerty. “Ideally, streaming media servers should be sited in close proximity to the end user." Sometimes more than one media streaming company will be needed to meet the demand. MSN, organisers of Madonna’s concert, employed NTL to provide
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the outside broadcast for the event, a live satellite feed and landline feeds. And it then commissioned a number of video streaming companies, each serving different geographical zones, to stream the concert to an anticipated audience of several million potential viewers worldwide. Virtue Broadcasting streamed the concert to audiences in Canada, Australia and across Europe. The relationship between video streaming companies and broadcasters looks set to get closer as the media streaming firms take on more and more functions. Virtue offers its streaming servers for off-line encoding of archived material. It also provides video archiving services and, to facilitate the exchange of information, it provides gateways to its content management system. Digital Rights Management and micro-billing services can also be offered.
Tony Orwin, sector manager of business and events television, NTL
Specialised media servers
Streaming servers provide a ready interface between content providers and the Internet. They are purpose-designed to encode and stream webcasts to hundreds - and thousands - of viewers in real-time, whether the webcast originates from a live event or an archived media file. For live events, the transmission cannot be saved on the viewer’s computer and true video streaming is essential. There will be a short delay on the client side as the
Grass Valley’s Profile XP video server
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streaming server buffers the content, then there should be no further interruption. This assumes that the network bandwidth matches the video streaming data rate. Modern media streaming servers can take an incoming MPEG-2 video signal and simultaneously encode it into the three compressed video formats in general use today, in real-time. These servers will also generate video streams at all common data rates including that for broadband cable, ISDN and dial-up modem. Then, when Internet viewers select the appropriate feed from an on-screen menu, they are attached to a port on the nearest streaming server. HTTP servers, used to host conventional Internet sites, can also deliver short video clips, but they are ill-suited to streaming live events. That is because the HTTP transmission protocol incorporates heavy error-correction mechanisms that force the re-transmission of lost data on web pages. This progressive download operation interrupts the playback process. Streaming media protocols such as Real Network’s RealSystem, Microsoft’s Media Player or Apple’s QuickTime dispense with the overhead of heavy error correction and are optimised to achieve high data compression ratios. Fortunately, the two technologies are complementary. For example, a conventional HTTP server can host a website while a separate video streaming network inserts streaming videos. The join between the two is hidden from the viewer. When the viewer clicks on a streaming video frame, a hot link connects him or her to the nearest streaming video server. Future distribution channels
Internet broadcasting is still at an early stage of development. Among those making the early Cable & Satellite International
HTTP servers are ill-suited to streaming live events. But they can host a website while a separate video streaming network inserts streaming videos. The join between the two is hidden from the viewer. running are CNN and the BBC which both incorporate sound and video clips on their websites to bring an immediacy to their news services. Clips can be viewed as low quality images on a PC using standard browsers, but audiences are still limited. The spread of broadband, based on cable modems and DSL technology, will open the market for Internet broadcasting. Today cable modem services from the likes of Telewest and NTL, the UK cable operators, offer bandwidths of 0.5 Mbps or 10 times that of dial-up modems. This is sufficient to support high fidelity sound, and is ideal for Internet radio. But acceptable full screen video services need a minimum bandwidth of 1.5 Mbps. In addition to the PC platform, other distribution channels and platforms are emerging. 3G mobile, PDAs (Personal Digital Assistants), pagers, games machines, set-top boxes and home gateways all create opportunities for new Internet broadcasting products and services. The prospect of repurposing content to fit each of these platforms might appear daunting, but the industry has already come up with a solution. The MPEG-4 international standard is intended to support the delivery of rich multimedia experiences over IP networks such as the Internet or 2.5G and 3G mobile radio. It supports video encoding from 5 Kbps up to 2 Mbps, while for audio streaming it is scaleable to cope with variable bandwidths. Thus it spans a range of applications
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from very low bit-rate mobile devices to full screen TV. Significantly, the MPEG-4 standard is platform-independent, so the same content can be displayed on a computer, a TV or a web tablet without modification. And as new Internet appliances become available, existing content can be displayed by porting an MPEG-4 decoder to the device. However, it is still early days. The Philips group was one of the first companies to come up with a complete MPEG-4 solution. Its WebCine product includes content authoring, encoder and player software. According to Shailendra Jain of MP4Net, the Philips Digital Networks unit formed to exploit the new standard, “MPEG-4 is already the encoder of choice for new mobile, set-top and other new platforms.”
ContentShare from Grass Valley Group
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