VTC Leaps Ahead with NDI-Based Master Control
July 02, 2020 by Ellen Camloh
VTC Digital Television is a multimedia organization that’s consistently focused on ways to stay ahead.
Starting in 1988, it was the first to provide post production, transmission and broadcast to all TV stations in in Vietnam. In 2009, it was the first to provide HD broadcast; and in 2017, the first to trial 4K video transmission there as well. Even the company’s mission statement reads like an homage to cutting-edge technologies:
To satisfy VTC’s customers with high-end quality and premium technology at a competitive price, and be profoundly engaged in making Vietnam a pioneer in strong information and communication technologies.
This bold mission reflects the government’s ambitious goal for television in the nation: to digitalize the transmission of Vietnam’s terrestrial broadcasting by 2020.
Now VTC, wholly owned by Voice of Vietnam, is building the foundation to achieve it, one master control room at a time.
Heartbeat of the station
Nguyễn Huyền Diệu, owner of broadcast-industry software company HD Vietnam in Hanoi, saw an opportunity to move VTC forward when the organization built a new building for its television station. VTC wanted to migrate from the old SD/HD facility to all HD video transmission, creating the need for master control playout of multiple TV channels.
“The new master control room will be the transmission center for 16 television channels fully ready for air,” says Dr. Diệu. “It’s essentially the heartbeat of the entire TV station.”
The facility needed to accommodate playout of all channels simultaneously, each of them with full channel branding and live video input. The programs would need to publish the live transport stream directly from the master control room—or MCR—both for OTT delivery and the headend. All fairly conventional requirements by master control standards.
But VTC had even more in store for its new MCR in its journey to fully digital transmission: it had to be built with the ability to upgrade transmission to 4K—at any time.
With existing baseband equipment too outdated for these requirements, and a limited budget, HD Vietnam led VTC’s project down a new path: IP video transmission.
Breaking the chains
Imagine the logistics and expense of wiring a complete facility with SDI connectivity.
“If you build a TV station the traditional way, your MCR will have a lot of cabling coming in from pretty much all the sources in a station,” says Dr. Diệu.
Compared with a typical production room, where you might have ten to twelve sources, and need maybe a 16 x 16 router, he says, “in MCR you’re talking about 3 studios, a few other NLE stations, newsrooms, sound rooms. All of the cables from all of the sources in all of those rooms have to come to MCR.”
In that scenario, a typical master control room would of that size would essentially represent a 144 x 144 router. “Then include redundancy, clocking, monitoring—all this stuff in the master control room,” he says – “and that’s how much cable we’d normally need.”
But VTC, and HD Vietnam, knew that to move ahead, they’d have to remove the dependency on cable—and even, to a degree, on hardware.
Leading with software
Twelve years ago when Dr. Diệu started developing software for HD Vietnam, “it was pretty much baseband – we were basically building software-controlled hardware solutions in traditional infrastructures,” and modernizing workflows at traditional facilities with software.
After having implemented several of these integrations, the developers found a highly innovative way to execute many conventional broadcast operations in software, thereby reducing the expense of multiple pieces of equipment.
Says Dr. Diệu, “As soon as you have video ingested into the software, this one integration can take it over completely until you go on air.” Management, review, master control playout–all of these can take place in software, without the need for multiple handoff points where transcoding would be required.
For HD Vietnam, NDI is the platform of choice for IP video. “Only NDI is resolution independent. Because of NDI, this system is the complete solution for working with SD all the way to 4K,” says Dr. Diệu. Performance-wise, it offers the lowest delay on the system and puts the least burden on an IP network, he says.
The HD Vietnam team proposed its software solution, a Router-Gateway-Multiview in one unit based solely on NDI, as well as its groundbreaking NDI-based black synchronization signal, an innovation that allows all playout servers to be synchronized over IP.
Serious about IP
The VTC staff had a robust plan and clear definition for the IP route, as well as strict system requirements for the MCR that supported their leadership in providing media. For instance, playout must be synchronized between servers and live input; routers need to automatically change the IP signal on fail over; multiview must display the IP signal; and gateway must do IP-SDI conversion on request.
After thorough exploration into the available technologies—evaluating both SMPTE 2022 and NewTek NDI® and consulting with HD Vietnam on its gateway software—VTC concluded that SMPTE 2022 was too far away for broad implementation, and they couldn’t use it with 4K in the near future. The team decided to move forward with NDI.
They also found that using NDI, “the entire TV station’s process in the MCR could become really clean, with everything on IP,” says Dr. Diệu. “As soon as it hits the gateway it is converted to NDI and then never touches baseband again”—cementing VTC’s advancement toward complete digitalization.
Now, VTC is once again pioneering the use of technology, as the first television provider to implement NDI for fully IP master control transmission.
But it went one step further.
Running on Time
Traditionally, baseband broadcast facilities use automatic failover to immediately switch to “input B” so the program still goes on air without a glitch when the first input encounters a problem.
That requires the feed to have a primary source – and a backup source in case the primary one fails. Because of the nature of video signals, this switchover is virtually undetectable using traditional broadcast technologies.
However, no matter how clever people try to implement automatic failover in an IP video workflow, it is never undetectable – the switchover is never quite seamless. But HD Vietnam devised a solution for this problem too.
VTC implemented NDI with two servers, both servers playing the same content at the same time. The NDI router monitors both NDI streams constantly, so if it detects failure on the primary NDI source, it can instantly and automatically switch to the backup source.
Additionally, all signals on the system need to be synchronized to professional television standards. HD Vietnam took another software-based approach to achieve this task—one that’s simply a given in baseband master control facilities.
“We keep the signal in the NDI path, and do not use video card I/O in our solution, so all NDI in the system must be genlocked to black,” says Dr. Diệu. So they programmed the NDI gateway to transmit genlock to all NDI sources. That way, he says, all NDI signals are genlocked with house timing.
Dr. Diệu says, “NDI is so flexible that we were able to fully adapt it into a fully IP master control system with accurate timing, routing and monitoring. Thanks to this integration, switching NDI can be entirely synched within the standards of professional broadcast—and it’s completely seamless.”
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