Q&A: Technicolor’s Alan Stein on Las Vegas ATSC 3.0 Tests

Methodology accommodates receiver diversity
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PRINCETON, N.J.—The storied name “Technicolor” continues to break ground in media development, most notably in recent technology trials for an entirely new method of transmitting television over the air known as “ATSC 3.0.” Technicolor contributed content and prototype reception technology to the simulations, which took place last month in Las Vegas with Sinclair Broadcast Group and ONE Media. (See “Sinclair Demos HDR 4KTV Over ATSC 3.0 in Vegas.”)

Alan J. Stein, vice president of Technology, Corporate Development and Technology Office for Technicolor USA, fielded questions from TV Technology about Technicolor’s participation in the trials.

TV Technology: Alan, tell us the nature of Technicolor’s contribution the test of ATSC 3.0 transmission in Las Vegas earlier this month with Sinclair. Technicolor essentially wrote the algorithm used in the Ateme single-pass decoder, correct?

Stein: Technicolor contributed several components to the Sinclair Las Vegas test. We provided the pre-encoded SHVC [scalable high-efficiency video codec] HDR [high dynamic range] content, which utilized a base layer at 1920x1080 resolution and a spatial enhancement layer, increasing the resolution to 3840x2160.
We also provided a streaming server employing MPEG-MMT [MPEG media transport] transport, a real-time SHVC decoder/player for the UHD 4K display, and a real-time HEVC decoder/player for the HD and mobile receivers.
Ateme’s live broadcast encoder was used in an offline mode to create the streams; we did not shoot live UHD+HDR video in this test, but stay tuned.

TV Technology: Why is SHVC an important component to the new standard? Why not ordinary HEVC?

Stein: SHVC refers to a set of tools standardized in HEVCv2 that enhance HEVC to offer scalability. ATSC has focused on spatial scalability to efficiently address ATSC 3.0’s UHD and mobile TV requirements.
As we have shown in previous over-the-air tests, having an HD base layer video stream transmitted on a robust PLP [physical layer pipe] provisioned for mobile reception, plus a UHD enhancement layer transmitting on a highly efficient PLP designed for only fixed reception, offers broadcasters a way to reach all ATSC 3.0 devices simultaneously, with far greater efficiency than simulcast.

TV Technology: So SHVC allows a broadcaster essentially to tier a signal into a base layer and an enhanced layer that would allow simultaneous broadcast and OTT payloads, for example. Would you elaborate further?

Stein: Some broadcasters have expressed strong interest in ‘hybrid’ delivery schemes, to conserve their [over-the-air] bandwidth and supplement this transmission with OTT streams.
One example is as you note: an HD base layer signal would be broadcast, and an enhancement layer would stream OTT. These would be combined at the receiving device.
Another use case of interest is to offer alternate language or enhanced-quality immersive audio signals via OTT streaming. The MPEG-H audio codec proposed for ATSC 3.0 is capable of such scalability.

TV Technology: Is the dividing line between those those layers dynamic, similar to adaptive bitrate technology?

Stein: Encoders can dynamically adjust the bitrates of each layer, such that statistical multiplexing could be supported. If by “adaptive bitrate technology,” you refer to HTTP streaming such as MPEG-DASH or Apple HLS, I’d note that the use of scalable video in broadcast is addressing a slightly different paradigm.
Scalable video assumes a point-to-multipoint delivery mechanism and different classes of service, and offers robustness to overcome the “cliff effect” we see with a single broadcast stream (e.g. ATSC A/53.) That is to say, if a two-layer signal is broadcast and the receiving device is only able to receive the base layer, that base video can still be decoded and displayed, instead of experiencing a total loss of signal.
Internet adaptive streaming addresses robustness as well but solves a different problem, that is, one where the bandwidth available is varying due to network congestion. Since Internet streaming is unicast to each device, the service switches between streams of different bandwidths. This technique is very effective when multicast is not available.

TV Technology: Are there any other applications or implementations of SHVC?

Stein: Previous scalable video coding standards (e.g. SVC) have been deployed commercially for Internet videoconferencing applications.
In the broadcast space, Ateme is the first encoder company announcing support for SHVC. Technicolor first demonstrated real-time SHVC decoding capabilities at NAB 2014 and it is expected that commercial SHVC decoders will become available in time for ATSC 3.0 trials.

TV Technology: Are there any other flavors of SHVC in development?

Stein: The HEVC extension activity that brought SHVC tools into the standard is now complete.

TV Technology: What did you learn from the Las Vegas ATSC 3.0 transmission test? Where might the technology bear improvement or modification?

Stein: This was our first experience with integrating with ATSC 3.0 physical layer equipment. While it is similar to DVB-T2 (European digital terrestrial television standard), obviously, it is less mature.
In this test, we were working with prototype equipment at the physical layer. From the ATSC point of view, itwas very important that the physical layer be proven. What we saw for the first time is that the ATSC 3.0 physical layer is able to transmit IP video and audio efficiently. That had not been done before.To my knowledge, this was the first time an ATSC 3.0 physical layer implementation had actually carried video and audio on a live, over-the-air system.

TV Technology: When will we see a public demonstration of this ATSC 3.0 transmission methodology?

Stein: A public demonstration is imminent, but it is up to others to make that announcement.What I can say is that we are well beyond the proof-of-concept phase for ATSC 3.0. The Las Vegas test proved that we are abletodevelop practical and implementable television applications based on ATSC 3.0.

TV Technology: Can you give us an idea how much it will cost broadcasters to transition to 3.0?

Stein: While that is a great question, it is not a simple one. The goal of investing in ATSC 3.0 is not simply to replace the functionality of existing technology. This is about introducing an entirely new system supporting a variety of business models that will allow broadcasters to reach new markets in new ways.
Therefore, the investments need to be viewed in the context of the opportunities that will be raised and created.A number of analysts are in the process of quantifying the required investment and potential return of various deployment scenarios.