Advanced Television

NHK to broadcast 8K terrestrially

September 16, 2019

By Chris Forrester @ IBC

Japan’s public broadcaster NHK, which is now transmitting 12 hours a day of 8K content on its satellite BS service, is working hard to make that content available to viewers at home.

NHK sources speaking at IBC in Amsterdam said the major problem they had to overcome was that of digital compression.

NHK’s ‘Super Hi-Vision’ roadmap is building towards starting 8K terrestrial transmissions in approximately 2025. NHK’s Science & Technology Research Laboratory has already successfully tested 8K terrestrial transmissions as far back as 2012 using a single UHF channel.

More recently similar full terrestrial transmission tests have taken place in Tokyo and Nagoya and subsequently delivering high-resolution signals over its satellite channels (in 8K) ahead of the formal start of the service on December 1st 2018.

The satellite bit-rate, currently around 100 Mb/s uses HEVC as its codec. “But this will not be sufficient reduction,” said our source. “Instead we are focusing on the Versatile Video Codec (VVC).”

VVC is a development of the Joint Video Experts Team and MPEG, and experts say that bit-rates of 30-35 Mb/s should eventually be achievable. The recent 8K tests at the Roland Garros tennis tournament were run with 5G cellular in mind (and organised by France Televisions with help from Harmonic, Huawei and Samsung).

Work is still being done and a final specification for VVC will not emerge until 2020 and implementation around 2022. NHK intends to also embrace Hybrid Log Gamma into its 8K signals for backward compatibility.

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