Broadcasters are in the midst of a giant transition — from creating and distributing one version of one channel to one delivery system, to delivering multiple versions of multiple channels through many delivery systems. The simple days of a single analog channel are gone forever.
Today's viewers expect their content over every delivery platform — appropriately branded, edited and conformed. This puts broadcasters in the curious position of having to determine the best formats and distribution techniques for each channel on each delivery system. Call it multiplatform or multiscreen delivery, today's broadcasters are challenged with the same moving targets of providing more and more different types of program feeds all in different formats.
Additionally, there is the challenge of fitting these new tasks into existing workflows. Technology aside, broadcast operations typically are governed by strict organizational and management responsibility domains. Which department holds the responsibility for reformatting and distributing in all these different formats?
Problem solved
To address these new challenges, Harris has developed a media convergence platform that simplifies your multidistribution workflows and signal flows. The Selenio media convergence platform combines traditional baseband video and audio processing, compression and IP networking features — all in a single, space-saving 3RU frame. A GUI based on Microsoft Silverlight technology simplifies the management and monitoring aspects, and keeps the configuration process workflow-oriented by following a series of graphical block diagrams instead of being weighed down with user manuals and bespoke commands. (See Figure 1.)
The media convergence platform quickly aligns broadcasters with the moving targets of the multimedia explosion for audio/video, analog/digital, baseband/broadband and, most importantly, the high-quality signal processing and compression for which Harris is well known.
Case study
Let's look at an example application in more detail. A broadcaster has three programming channels prepared for distribution: two HD entertainment channels and an SD news/weather channel. Outputs are required for an ATSC terrestrial transmitter, local cable headends, IP mobile feed for the ATSC M/H system, internal monitoring IP feeds and Internet distribution feeds. To complicate things further, various audio configurations exist for the different feeds.
Using traditional equipment, with a degree of redundancy, 45 separate functional items are required. This includes frame syncs, video format/aspect convertors, Dolby E decoders, MultiMerge processors, loudness processing, and a variety of video and audio compression encoders and multiplexers. IP processors, Ethernet switches and redundancy management controllers round out the rack infrastructure. A total of 25 rack units, more than 130 cables and around 2500W of power are typical for this approach. Configuration, management and monitoring of all this equipment present an additional operational challenge.
United States Europe Figure 2. Using the Harris Selenio media convergence platform, a typical multiplatform system is reduced from 25RU to 3RU.
Taking the functional convergence mindset of Selenio, all these functions are consolidated into a high-density integration platform, as shown in Figure 2. Space, power, cabling and operational complexity are reduced by 75 percent. There is no reason to waste the equipment cost, real estate and doubling of functions when the sensible alternative is finally at hand.
Benefits
Looking at the complex requirements for each delivery platform illustrates the advantages of taking the convergence-platform approach:
- Signal preparation preparation: Video and audio signals from the plant arrive as HD-SDI but over fiber due to the distance involved. The fiber needs to be terminated, the signals synchronized to plant timing and static delay adjustment applied to the audio to compensate for the plant. The video requires format conversion and ARC for some delivery systems, as well as the associated reformatting of the captions and other ancillary information in the video signal.
- Audio preparation: HD network programming typically has 5.1 audio; the local newsroom produces stereo only, and syndicated content is all over the map. Playout and master control use Dolby E to facilitate the multichannel audio. At this end of the chain, the Dolby E must be decoded to PCM. A MultiMerge algorithm is used to create a consistent 5.1 upmix of the audio, and also a stereo downmixed version; these are each subsequently loudness-managed for CALM-act compliance. Visual Description Service audio is also processed for each program.
- OTA transmitter feed: A heavily compressed statistical multiplex is used to fit the two HD signals and one SD signal into the ATSC modulator, while leaving room for a mobile service. The HD programs for the OTA transmission are crossconverted to 720p to optimize picture quality at this high-compression ratio. MPEG-2 encoding with Dolby Digital audio is used.
- OTA mobile transmission feed: The mobile feed is also created, including downconversion of the source video and downmixing of the 5.1 audio into stereo. CALM-compliant loudness control is applied on all audio signals in this transmission multiplex. This feed uses H.264 video encoding and AAC audio.
- CATV headend feed: The delivery to the local cable operator is not constrained by the same bandwidth limitations as the OTA transmitter. Many stations today create an alternative multiplex for delivery to cable headends, with a lower compression ratio. In our example, while the HD programming on the OTA channels is in 720p, the cable delivery is in 1080i format.
- In-plant monitoring feed: In the old days, an analog in-house CATV was used so everybody in the building could watch the air signals. Now that PCs and LANs have invaded the facility, an IP version of the feed, suitable for decoding on desktop PCs, is another version to be generated from the TX room.
- Internet distribution feed: Increasingly, a live feed of the station is streamed for online viewers. H.264 video with AAC audio also is used for this feed.
A complete redundancy architecture is enabled by consolidating all of the processing into the media convergence platform. Every element of the air chain can be backed up 1:1 or 1:N as appropriate, and management of redundancy changeovers is accomplished through the convergence platform. Further, the media convergence platform exports a unified management interface, including a unified dashboard suitable for operations monitoring. Alarms and alerts are clearly displayed, identified down to interfaces and modules.
A tool for the 22nd century
The media convergence platform provides savings of space, power, cabling and operations monitoring/management complexity. This example clearly illustrates the TCO savings of the convergence platform mindset: 2500W to 600, 25RU to 3RU, and 131 cables to 14.
Similar savings are documented at other workflows in the plant, including content acquisition/prep and signal processing for newsrooms and remote feeds. The Selenio media convergence platform is designed to be the next generation of infrastructure for the 22nd century television operation.
Stan Moote is vice president of business development, and John Mailhot is director product architecture at Harris Broadcast.
