SMPTE 2011: Remote and Mobile Monitoring of On-Air Signals For Centralcasters
HOLLYWOOD: Hello. This is NBC calling. We want remote monitoring of our 10 TV stations and multicasts with discrete, full-resolution channels, and multiviewers for each channel group, distributed across multiple platforms.
“Within 30 Rock, they wanted them on digital and analog baseband infrastructure, in-house QAM distribution, Internet streamed and to air-check recorders,” said Michael Wright of TI Broadcast Solutions Group. “And they wanted to do it with minimum financial outlay.”
Wright’s team brought discrete channels into TI’s Atlanta hub into a multiviewer via HD-SDI, then encoded them for traffic down the line, he said. Individual program streams were downcoverted at the hub for the multiplexer. From the multiplexer, they came out ASI and were put through a transport stream processor, then moved across the MPLS IP WAN, on to the decoders for the network. No new network was created for this, he said.
TI used a single 16-input multiviewer and fed it baseband. They had HD channels, SD encoded downcoverted signals, and HD encoded multiviewer output. They wanted to keep the signals HD in the multiviewer because they’d be windowed fairly small, Wright said.
The primaries were HD, but not the dot-twos, which were SD from the start. TI used an existing IRD, passed them through to the multiplexor and HD encoded them for the multiviewer.
“The real key to the project came when it was time to remux,” Wright said. “As we set out to determine the bit rate, we had to consider the WAN bandwidth and the target distribution methods.”
Again, NBC wanted the signals Internet streamed, distributed on the digital and analog baseband infrastructure, in-house in QAM, and to air-check recorders. The challenge was creating a remux of the 10 discrete HD streams of the stations, and get them back up to New York.
“We came up with a single-threaded approach,” he said. “We used a daisy chain of 10 encoders to the multiplexor. Each is at 3 Mbps, so you end up with 30 Mbps. We had set our multiviewer at 5 Mbps, meeting the payload limit of 38.8 Mbps. We didn’t have to apply the daisy chain to the SD nonstop channels. All 10 of those were simply fed into the mux. And so, what we wind up with is, two program streams... going from Atlanta to New York--one for the flagships and one for the nonstops (SDs). New York then gets NBC HD multiviewer; HD NBC channels converted to SD; the SD nonstop multiviewer stream, and the SD nonstop channels.”
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