There are three SHV cameras (the only three operational SHV cameras in existence) in the Olympic Park. They are connected to NHK’s Outside Broadcast vehicle so that the pictures from the cameras can be selected to be sent to the SHV Production Centre at BBC Television Centre. The pictures can also be recorded in the vehicle. There is a separate sound vehicle (based on a converted refrigerated truck), supplied by SIS Live, kitted out with an audio mixing desk and a miniature 22.2 multichannel sound system provided by NHK. Audio from NHK’s own microphones and from the shared microphones in the Olympic Park are mixed in the audio truck into 22.2 channels and sent to the SHV Production Centre for further refinement in a room kitted out for audio editing. The connection from the Outside Broadcast vehicles to the SHV Production Centre is via an optical fibre link carrying the SHV uncompressed at 24 Gbit/s
over eight wavelengths. For security, there is a backup fibre link taking a different route across London.
The SHV content has 16 times the data of HDTV, so rendering and processing time is slow, even using very powerful workstations. Even so, the NHK production team and a BBC editor are able to edit a new content package overnight ready for showing the next day. There is also a dedicated SHV graphic station used to add captions and make up titles sequences.
(Interesting to see what NHK is using for a workstation, because the photos show Windows 7. Sun OS or IBM?)
The transmissions to Glasgow and Bradford are carried to the theatres over Janet (Joint Academic Network), with the final link to the BBC studios in Glasgow over a link provided by BT. Geant2, Internet2, Sinet4, and GEMnet2 research networks coordinated by NTT are used for the links to the USA and Japan.
This has been a project long in its preparation, with first test transmissions of a live pop gig by the Charlatans from London to Tokyo in September 2010. Network tests across the UK and from the UK to Japan started in winter 2011/12. The network link to the National Media Museum had to be upgraded from 100 Mbit/s to 1Gbit/s. In Glasgow, BT provided a link from Glasgow University. Soak testing of the link has been going on for several months, during which several problems were found and solved. As I finish writing this post, we are into the fourth day of the Olympics. The links have been reliable, with only one glitch that has occurred during a show in the UK so far. Even so, we are investigating why there was a glitch. We have shown that IP networks can be made to reliably carry high bit rate time critical video and audio, but care is need in the way the links are set up. It is not clear to me that all the interaction mechanisms on IP networks are well-understood; an area for further research, perhaps.
(The question is in 2020, will 8K be ready for the Home? How much backbone is going to be required for Next gen Internet?)