TVU Ready for 8K Distribution
One of the capabilities that TVU Networks highlighted at NAB Show 2022 was their ability to ingest, encode and distribute 8K signals at up to 600 Mbps. They have demonstrated such a capability by modifying their G-Link appliance as a proof of concept device. “We have not yet commercialized this,” noted TVU’s Matt McEwen, “but we will when there is customer pull for it.”
TVU’s existing G-Link device features a single 12G SDI interface for content ingest and supports 10-bit 4K 50/60p transmission. TVU uses its proprietary IS+ protocol to manage the transmission of this video over an open IP network. Initially, this protocol was developed some time ago to help bring stability to unmanaged open IP networks for video transmission. It is often used for point-to-point transmissions such as network-to-affiliate or station-to-station transfers. But it also supports multicasting, allowing a single ingest and distribution to many endpoints. McEwen said that they had shown end-to-end latency of less than 1 second for coast-to-coast type transmissions, which customers find very acceptable.
McEwen said that developing the 8K proof of concept required some engineering work that came together surprisingly well. First, input to the 1RU G-Link box needed to be upgraded to support a 4x 12G-SDI interface for 8K content ingest. “This was easily solved with plug-in boards that support this capability,” noted McEwen. This allows ingesting of 8K content in a square division or 2SI format. The HEVC encoding was also tweaked to support 8K 50/60p signals with 10-bit and 4:2:0 color sub-sampling. McEwen declined to provide any details on their encoder, however. “We are looking at doing 4:2:2 encoding now,” he added, “and we can support 16-channel audio.”
TVU also needed to look at their IS+ management plane for the IP network transmission. This algorithm required to be upgraded to support the higher bandwidths for the 8K signal and was apparently accomplished with adjustment to the Forward Error Correction (FEC) parameters. TVU says they can send 8K signals in a Variable Bit Rate format from 60 Mbps to 600 Mbps, which means they cover the full range from contribution to distribution needs.
McEwen says they are starting to see interest in 8K transmission from sports and event broadcasts, but there might not be a bigger draw for this device for the distribution of four 4K/60 signals.