After IP, Satellite and Mobile Networks, Live 8K gets a Spin Over Spanish Terrestrial Network
In December 2018, NHK commercially launched its 8K Super High Vision using satellite transmission. Six months later, in spring 2019, live 8K streams were transmitted over a 5G network during the Orange PoC at the French Tennis Open.
At NAB Amplify Spanish engineering company SAPEC described another successful trial of 8K transmission over a DVB-T2 terrestrial network with the national public broadcaster RTVE last fall. They have recently posted some interesting analysis on those trials.
A short note on bitrates
Information on bitrates needed to stream or broadcast 8K is often difficult to decipher. Here’s what we know.
To transmit 8K over a distribution network, video needs to be encoded in one of the more recent CODECs such as HEVC or AV1 – H.264 won’t cut it.
In theory, to preserve quality and 120 FPS at 12-bit color depth, approximately 200 Mbps would be required using HEVC. However, in the real world, compromises occur and most early trials we are aware of for live feeds used just north of 100 Mbps.
The world’s only commercial channel mentioned above launched at that bitrate over a satellite network.
On-demand content can benefit from much more aggressive compression algorithms that might, for example, enable a multi-pass. When optimizing to save bandwidth, 8K on-demand content can be lowered below 40 Mbps. When Google first trialed 8K over IP they required a connection of at least 50 Mbps.
When using the latest Content-Aware-Encoding (CAE) techniques, 8K streams have been demonstrated below 20Mbps.