New Broadcast TV System Might Be Coming Soon
If all continues to move smoothly, the United States could see a new digital television broadcasting system in as little as five years, eventually bringing with it up to 8K resolution images, high-dynamic range, a wide color gamut, 3D video, 3D object-based immersive audio, interactivity and over-the-air broadcasting to mobile devices as well as the home.
And unlike the last digital transition, which took decades and billions of dollars to develop and implement, the next generation Advanced Television Systems Committee (ATSC) 3.0 system should come about much more swiftly, and possibly rolling out on a market-by-market basis.
More on the ATSC 3.0 platform after the jump:
One of the obstacles facing system implementation is that it won’t be compatible with the current ATSC 1.0 broadcast system, which means another full-scale system transition, like the analog-to-digital conversion.
But this time around there won’t be the kind of money or available bandwidth to provide for set-top converter boxes or simulcast channel broadcasts. In addition, the transition might not be accomplished on a nationwide plan but by broadcasters working voluntarily in each given market, using channel spectrum sharing and other methods, among some of the proposals.
As for hardware, the designers of the ATSC 3.0 platform are currently looking at proposals that could make receiving the broadcasts on a TV today as simple as connecting a thumb-drive-like dongle to a USB or HDMI input. This would provide a more elegant solution than the digital set-top boxes that the government handed out the last time around.
In addition to providing TV viewers with a range of new capabilities and features, ATSC 3.0 is being developed to keep over-the-air (OTA) TV broadcasters competitive with wireless companies like AT&T and Verizon. The wireless mobile providers also have large IPTV-based telco-TV pay television platforms and provide video services to mobile devices.
Although today’s ATSC 1.0 platform supports OTA broadcasting to mobile devices, that system was bolted on to the original home-based broadcast system and has not seen the broad-based support originally expected. Mobile transmission and reception will be more thoroughly integrated into the ATSC 3.0 standard, and will feature enhanced reception by moving devices. The robust signals are even expected to penetrate deep into buildings and other structures.
Balloting This Week
Representatives for the ATSC said the development process is moving along nicely, and a recommended ATSC 3.0 standard, called a candidate standard, could be in place soon. From there, implementation decisions will have to be made, including how to build the capabilities into equipment and determining the approvals that will be needed from Congress and the Federal Communications Commission.
This week balloting concluded on the first of a dozen different elements to the “physical layer” of the ATSC 3.0 system, which includes the modulation system, error correction algorithms, constellations and other aspects. There are three layers to the overall system, and voting on proposals for each element are going on in parallel. This first ballot for the physical layer covered the bootstrap (or preamble) signal, which provides the basic information that allows an ATSC 3.0 device to tune and lock onto a signal very quickly. The core elements of the physical layer are expected to be balloted for ATSC Candidate Standard status this summer. The bootstrap signal portion of the physical layer needed for ATSC 3.0 transmission will remain a Candidate Standard for nine months while prototype equipment can be built and tested in advance of balloting for the entire system, the ATSC said.
“Many other services, at least some of which have likely not yet even been conceived, could also be provided by a broadcaster and identified within a transmitted signal through the use of a bootstrap signal associated with each particular service,” said Mark Richer, ATSC president. “This new capability ensures that broadcast spectrum can be adapted to carry new services in the years ahead.”
Unlike today’s 8-VSB (vestigial sideband) modulation-based OTA broadcast system, which was originally designed for reception by stationary devices in living rooms, ATSC 3.0 is expected to use cell-phone-like single frequency network transmissions based on orthogonal frequency-division multiplexing (OFDM).
The OFDM system, used today in parts of Europe and elsewhere, is optimal for mobile reception because it uses a large number of closely spaced orthogonal sub-carrier signals to carry data on several parallel data streams or channels. It’s also much better at penetrating buildings and being received with fewer interference issues, because it will involve placing multiple transmission towers in a given city or market instead of just one.
“The ATSC’s progress on the 3.0 standard has been excellent. It’s the result of industry collaboration within the open process of ATSC,” Richer told HD Guru. “This week’s announcement that the first ingredient in the physical layer has reached candidate standard status is a good measure of steady progress.”
Interacting with Interactivity
In case you were wondering what happened to ATSC 2.0, which was a proposed system developed essentially to bring internet capabilities to the ATSC 1.0 system, with back-channel and interactive capabilities. Because technology was progressing so rapidly and work was advancing at the same time on ATSC 3.0, it is felt by some that the work that had gone into ATSC 2.0 should be implemented into ATSC 3.0, eliminating a transition step on the road to the future of television.
From 4K to 8K
Today the hybrid system is being designed with a focus on supporting broadcasts with up to 4K Ultra HD resolution, but theoretically it could support all the way up to 8K (along with multiple streams of mobile and other data) if the industry ever decides that’s a practical option for home TV viewing.
Using a system called Non-Real Term (NRT), one of the data streams in the signal could also be used to transmit metadata to a television or receiver outfitted to store a host of applications including DVR-like functionality, or targeted advertising, where ads specific to the interests of the viewer could be played back for maximum benefit to the viewer and the advertiser.
Another element of ATSC 3.0 will be expanded immersive sound. Major proponents for immersive audio for ATSC 3.0 adoption include — Dolby (AC-4), DTS (DTS:X) and a system from an alliance of Fraunhofer/Technicolor/Qualcomm (MPEG-H). The three proposed formats will be able to deliver 2.0- and 5.1-channel audio to TVs as well as “3D” object-based surround sound supporting 7.1+4 and 22.2 speaker systems transmitted as a metadata layer. The formats will be participating in audio tests throughout the summer prior to a selection process.
Dolby’s AC-4 soundtracks could be output as two-channel, 5.1-channel, or object-based audio through a TV’s HDMI audio return channel (ARC) to a home audio component. Two-channel linear PCM could also be passed through a TV’s optical output. Dolby has said that to play back multichannel content through a home audio system, the signal would be converted inside the TV to a codec an AV receiver could support. If the AC-4 soundtrack incorporates object-based audio, the soundtrack could be decoded by an HDMI-connected A/V receiver incorporating a Dolby Atmos decoder, with necessary metadata passed over the HDMI cable to the AVR.
Today’s Dolby Atmos receivers that don’t yet support AC-4 would be able to handle the object-based metadata passed through over HDMI.
DTS has also said that its newly announced DTS:X object-based surround sound system would be proposed for adoption in ATSC 3.0. The signal could be decoded on the receiving device; passed through the device’s HDMI out connection; or transcoded to DTS 5.1 and passed out the device’s optical or HDMI ARC connection. One high-quality signal would be sent out supporting objects and other capabilities for multiple playback configurations based on the abilities of the format and decoder.
The Fraunhofer/Technicolor/Qualcomm system is based on the new MPEG-H Audio international standard. Among other things, it would offer viewers the ability to choose different audio presentations, such as “home team” or “away team” commentary for a sports event, or volume control over specific audio elements in a program such as sound effects. Viewers also would be able to experience immersive sound over loudspeakers, new 3D soundbars, tablet computer speakers, and headphones. Additionally, it would automatically adjust playback for the best sound on a range of devices and listening environments from home theaters to earbuds worn on a loud train.
Whether or not implementation of ATSC 3.0 can begin within the next five years will depend on a number of variables, including how much support it receives from broadcasters.
On the good side, noted those involved with the ATSC process, broadcasters have been much more involved in the development of the standard than they were a few years ago. For one thing, several large broadcasting groups have started to approach it as an opportunity to get into the mobile broadcasting business. But the challenge will be convincing mobile device manufacturers and service providers to incorporate the new receiving chips for the broadcasts.
The technology is also expected to support conditional access capability so broadcasters could control access to certain programming for incremental revenue opportunities.
Business Model Confusion
One potential stumbling block to ATSC 3.0 acceptance is a varied level of support among some of the major networks. While all have been involved in developing elements of the system (some more than others), not all have been in agreement on the business model. But system proponents said their hope is to devise a system that broadcasters could implement voluntarily and without the requirement of a huge investment.
Where support appears to be growing is on the station ownership group level, where Pearl, a partnership comprising eight major station groups: Gannett, Hearst, Cox, Scripps, Graham Media, Meredith, Raycom and Media General, is actively involved with others in the system development. Pearl represents TV stations in 43 of the top 50 U.S. markets
Also to be determined in completing the final system are bandwidth needs. On the plus side, new compression systems like HEVC H.265, VP-9 and other standards will enable broadcasters to squeeze much more data into their spectrum allocations. At a time when broadcasters are being pushed by the FCC and others to give up some of their spectrum for auction to wireless services, the improved efficiency of ATSC 3.0 would give broadcasters greater incentive to do so.
Using the new system, broadcasters could potentially offer the same kinds of services they have today but do it with far less bandwidth. They might still be able to have a feed in 4K, HD and SD and do it in half the space. Some reason that this could give broadcasters more incentive to sell back a portion of the spectrum they have today.
One suggestion is for broadcasters who have multiple 6MHz channels today on VHF and UHF channels in a given market is to combine those channels onto a single channel. That way the broadcaster could return some of its spectrum to the FCC. This wouldn’t be feasible with ATSC 1.0, but could be with the advanced compression systems that will be employed in ATSC 3.0.
Among the transmission and reception systems under consideration for the physical layer of the ATSC 3.0 standard is “Futurecast,” a system developed by a team of LG, Zenith and GatesAir (formerly Harris Broadcast) and a system developed by the Sinclair Broadcast Group and Technicolor.
Both systems were recently demonstrated transmitting 4K, HD and SD images under a variety of conditions. Each system is comprised of different elements that are being developed and added to the candidate. Potentially, different elements from different systems could be selected and merged together into the finished standard.
Futurecast moves on from the 8-VSB modulation scheme developed by Zentih and Harris for the ATSC 1.0 system in favor of aforementioned OFDM technology. A primary goal in developing the system was to deliver a robust broadcast stream that could be received in areas with difficult terrain and receiving conditions.
In addition broadcasting 4K, the system can simultaneously transmit data streams carrying 480p and 720p video. The system can carry up to 26 Mbps on a standard 6 MHz TV channel. Using HEVC encoding Futurecast can carry 4K/30p video and several lower-resolution channels, in a similar fashion to the way TV stations offer secondary channels over ATSC 1.0.
Futurecast supports single-frequency networks, meaning that additional transmitters can be used on the same channel to fill in reception gaps.
The Sinclair/Technicolor has also demonstrated a system based on an OFDM transmission scheme, in order to add a large number of closely spaced orthogonal sub-carrier signals carrying data on several parallel data streams. The system is based on open standards (HEVC, SHVC, 3D Audio from MPEG-H) plus High Dynamic Range (HDR), with MMT and DASH transport streaming standards, and Technicolor’s Staggercast and Fast Channel Change technologies.
The demonstration under real-world conditions was said to have successfully delivered to fixed and mobile receivers high-quality HDR content broadcast at HD and 4K/UHD resolutions in a single-layer with backwards compatible standard dynamic range.
The broadcast met the most ATSC 3.0 requirements of any previously demonstrated system. Mobile tests yielded a received signal at up to 60 miles away and, separately, the receipt of the mobile broadcast signal at up to 120 miles/hour.
By Greg Tarr
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