While the current MPEG transport stream has worked well, it’s time for a change that will let over-the-air TV broadcasting break free from its own self-imposed silo and transition into something “that could be thought of as an extension of the internet,” according to Triveni Digital’s Rich Chernock. He details the ways such a change could benefit both broadcasters and viewers.
Six Reasons Why IP Is The Future Of OTA TV
The MPEG transport stream has served the broadcast television industry well for about two decades, providing the container format for transmission of video, audio and other data that makes DTV possible.
But all good things must come to an end, and it appears MPEG TS’s days in broadcasting are numbered.
“To be honest, there is nothing wrong with transport stream. It worked beautifully,” says Rich Chernock, chief science officer of Triveni Digital and chair of the Advanced Television Systems Committee technical group with overall responsibility for ATSC 3.0. “I think it was a brilliant design.”
However, the next-generation TV standard nearing completion by the ATSC and under consideration at the FCC ditches MPEG TS in favor of IP transport.
But why? Why replace a well-proven technology that delivers TV today to millions of over-the-air viewers with IP transport, and in the process ask viewers to make changes to their receivers and require broadcasters to make millions of dollars in new capital expenditures?
In other words, what’s the payoff for viewers and broadcasters alike?
Chernock, who later today will conduct a free online webinar entitled “Considerations for ATSC 3.0 Transport Over IP,” offers half a dozen reasons.
No. 1: Break Free From The Silo
TV doesn’t exist in a vacuum, and at the same time DTV was growing up, the internet exploded onto the scene as a behemoth entertainment delivery mechanism.
“If the internet hadn’t evolved the way it had, we probably wouldn’t have moved away from transport stream,” Chernock says.
By adopting IP transport to move video, audio and data, television can break free from its own self-imposed silo and transition into something “that could be thought of as an extension of the internet,” he says.
IP transport means delivery of digital bits — be they audio, video or other content — in a fashion similar to the internet, and in the process allows broadcasters to take advantage of the speed at which the internet evolves, Chernock says.
No. 2: Enable Peer Delivery Mechanisms
Once IP is used in television as the transport vehicle, some interesting new possibilities become available to broadcasters, Chernock says.
ATSC 3.0 incorporates the idea of the hybrid delivery of content. “Components of television services can come across broadcast, broadband or a combination and be synchronized,” he says.
In an MPEG TS-based system, the bits delivered via broadcasting were considered “kind of precious,” Chernock explains. “The earlier thinking was you don’t want to waste broadcast bits for something that has only a few viewers. You use it for things that have lots of viewers.”
However, when IP is the transport mechanism, the internet is available to augment bit delivery, which makes it practical to deliver niche content to viewers.
For instance, hybrid IP delivery via broadcast and broadband will give stations in markets where many different languages are spoken a way to better serve their audiences. While the video portion and the main and secondary audio channels of a program can be delivered to the mass audience over the air, delivery of less commonly spoken languages in the market can be done via the internet and synced perfectly to the OTA-delivered video.
No. 3: Create New Business Opportunities
Ad insertion is the bread and butter of commercial broadcasters, and here IP transport will create new opportunities.
“The ability to personalize ad insertion at the receiver will likely represent huge income for broadcasters, and this would be a very difficult thing to do using MPEG2 transport stream,” Chernock says.
Seamlessly slicing and inserting ads into a program stream is beyond the capabilities of today’s TV receivers, he says.
“But by switching to IP transport and using segmented delivery via ISO-BMFF [base media file format], it’s relatively simple to insert custom ad content delivered via the internet in a receiver.”
(ATSC 3.0 actually specifies two different IP transport mechanisms, both of which support segmented file delivery where a stream of digital bits is “chunked” into files. One IP delivery mechanism is ROUTE-DASH, or Real-Time Object Delivery over Unidirectional Transport and Dynamic Adaptive Streaming over HTTP. The other is MMT or MPEG Media Transport. Which one broadcasters use will likely be decided on a regional basis, Chernock says.)
No. 4: Access A Broader Development Community
The switch to IP transport and use of World Wide Web Consortium, W3C, technologies in ATSC 3.0 will also open up television to a whole new world of developers that have long built tools and apps for the web.
One of the first places this alignment of web and TV technologies is likely to impact television is interactivity.
“The model for the interactive framework is to use what’s been developed for the internet through W3C with the small changes,” Chernock says.
While a web browser doesn’t “know how to change a channel,” the model for interactivity is “to use exactly what’s being used in the internet,” he says.
Beyond interactivity, many new features and services can quickly be made available to television viewers because of the simplicity of porting apps developed for the internet to TV broadcast under 3.0, he adds.
No 5: Fewer Encodes
Today, TV broadcasters must encode their content for delivery as MPEG TS over the air and for the adaptive bitrate streaming via the internet.
However, in a 3.0 future based on IP transport, what’s encoded for over-the-air delivery is equally suited to streaming delivery via the internet. Thus, how many times content needs to be encoded will be reduced, Chernock says.
While it won’t collapse to a single encode — because different representations of DASH encoded content will be required for different bitrate levels depending on the available bandwidth of an internet connection — eliminating the MPEG TS encode will enhance workflow a bit, he says.
No. 6: Enhanced Non-Real-Time Services
The ATSC television standard has supported non-real-time content delivery since ATSC 1.
This non-real-time (NRT) content can be used to give viewers a sense of interactivity by allowing them to access content pushed and stored on the receiver in advance of the time it is needed.
In an IP-based ATSC 3.0 future, these non-real-time services can be enhanced, offering a new level of flexibility, Chernock says.
NRT service “is a bit easier to do with IP,” he says. “The really funny thing is that even live streaming television is delivered as chunks of files, so everything in ATSC 3 is really file-based.”
While Chernock calls the distinction between MPEG TS and IP in regards to non-real-time service delivery “subtle,” the difference will make NRT content delivery simpler, he says.
Fade To Black
The bottom line when it comes to the transition from MPEG TS to IP delivery is that the change is more about television coming into alignment with the internet and a “more natural growth path” that “has taken over the world,” Chernock says.
“It’s not that transport stream has problems, or issues or is bad,” he says. “It’s just that IP is more of the future.”
(Editor’s note: Rich Chernock will present “Considerations for ATSC 3.0 Transport Over IP,” an hour-long webinar today starting at 1 p.m. ET. Chernock will discuss the advantages of IP, the background of the technology, including ROUTE, DASH and MMT and look at some of the changes that will be required at the station in an ATSC 3.0 IP-based future. There is no charge for the webinar, which he says is educational, not commercial, in nature.)