The Sport Thread

Do you think it's the encoders out to the house or the encoders to the OB truck? What pictures were the most troublesome - the leader cam where a motorbike or car is ahead of the leader?

Anyone got any details on how it was rigged together?

It was done by CTV, here's an article about the engineering of last year's event

http://svgeurope.org/blog/headlines/keep-on-running-ctv-discusses-london-marathon-ob-challenges/

I know how it used to be done...

There are a handful of full OBs at points along the route: start, finish, Cutty Sark, Tower Bridge (the route passes there twice) and Canary Wharf (ditto). Then there's two helicopters for aerial shots, plus a handful of motorbike cameras. Finally, there's a light aircraft as a receive point for the motorbike cams, and someone got the fun job of standing on the ground all morning with an SHF receiver on a tripod, pointing it at the plane.

Until 2012, this would all go into TC5 at TV Centre, who would make two programmes out of it: the domestic BBC One/Two transmission, plus a world feed. (I think one year there was a third gallery in use that had been hired out by a Japanese broadcaster for their own coverage).

Since Sport moved to Salford, I believe they've been using one of the OBs (I'm fairly sure it's the one at the finish) as a hub point. What I don't know is how they're getting all the feeds back to there and back out again, and whether it means there's some double-encoding going on. I'd have hoped that would be the kind of thing that they'd work to avoid in the planning stage.

(As a trainee, I spent one London Marathon with the comms guys at the Tower Bridge OB. One of the jobs was rigging an SHF link on an 8th floor balcony of the adjacent hotel back down to Crystal Palace, from where it was fibred back to TVC. I think the receive point has since been decommissioned.)

They used not to always hub it in TC5. In earlier years, before hubbing in TC5, they would use the CMCCR on location to combine the outputs from various OB trucks (aka scanners) along the route, along with radio cameras etc.

The CMCCR was a massive truck with very few cameras - in the early days none - which was designed for linking multiple sources together. There were a couple of versions of the CMCCR - all with custom 'stretched' vision mixers, as you couldn't buy off-the-shelf models with enough inputs and buttons. It used to do the Golf, BBC One and Two presentation at Wimbledon (where two networks were fed from a single studio and truck), the Marathon, State Events etc. When there were very large multi-source events coming into TV Centre you would sometimes see the CMCCR parked outside handling hub duties.

The pictures from this year's marathon were particularly miserable though. It looked like multiple compressed circuits (and on the highlights server/edit compression too) all at too low bitrates for the concatenation that took place, with multiple encode/decode processes.

Not sure what you mean by 'out to the house'? Not a term ever used in the UK.

If you mean the backhaul circuits that get the final programme feed to Ericsson (who handle BBC One playout) or Salford (if it went through a BBC Sport gallery in Salford - which I don't think it did) - I doubt they were solely the cause.

Or do you mean the encoders used for emission encoding at the final stage of DVB-T2/DVB-S2 coding and mux? (i.e. generating the data stream we receive at home?)

I suspect it was low-ish bitrates being used on RF camera links - as there are LOTs of RF circuits around so they are probably tight for bandwidth, and also running at low bitrates to keep the circuits as robust as possible (you trade off final bitrate for error correction and robust modulation AIUI) They probably also used RF links along the route to backhaul the truck outputs at various points in the route back to a single combining truck where the show was knitted together.

The final output to BBC One playout will also have been a compressed circuit - so it's entirely feasible for a camera feed to have been through 3 code/decodes en-route to BBC One (4 if the RF midpoint plane was decoding and recoding rather than just RBRing the compressed stream - though I'd expect the latter) and 4 or 5 by the time it reaches viewers at home (more in highlights production)

Yeah the leader cam seemed to be the worse I thought it might have been the encoders but watching the 4:2:2 feeds at 24.5w looked like it was at source.

Sorry, I wrote the post as I was falling asleep. By out to the house I was referring to the encoders at the transmission point to the viewer so DVB-T2/DVB-S2.

Not sure if this is a first but RTÉ are letting Joanne Cantwell anchor tonight's live Champions League match.

While I've never seen her anchor Champions League before, she anchors rugby union coverage on a relatively regular basis and has anchored GAA in the past.

She has never been the main anchor for the Champions League before but she used to do the highlights reports and links from the other side of the studio which incidentally Darragh Maloney used to do when Bill was presenting. She has also hosted League of Ireland for RTE and TV3 as well and she was also involved with RTE coverage of FIFA World Cup in 2014 on highlights and as you say hosted Pro 12 Rugby, Irish Open Golf & Against the Head although I never realised she hosted GAA.

GAA is her own sport - she played for Dublin ladies many years ago.

I wonder if they are going to give her a role hosting during the Euros? Peter Collins would also be under consideration there, although I suspect he and Tracy Piggot will RTE's Olympics coverage.

On a different Irish sporting note, TG4 will employ the red button on Saorview and Cula4 on cable to show one of tomorrow nights Pro12 games (apparently Connacht v Treviso) with Munster v Edinburgh on the front channel. Sky fans out in the cold again - had they put Munster v Edinburgh on the red button, Sky viewers would at least have had the chance to watch on BBC Alba.