25/09 High Frame-Rate Television

My colleagues and I from BBC Research had a fantastically successful time a couple of weeks ago at IBC, Europe's huge annual convention and conference for the broadcast community. We went there to shake things up a bit, feeling that proposals for improving the quality of television (including High Definition television itself, frankly) had concentrated too much on improving the spatial resolution (the number of pixels) while completely ignoring the temporal resolution (the number of frames per second). Television is, after all, about moving pictures.

By the end of the week, we'd shown our demonstration of the benefits of higher frame rates to hundreds of people, who almost without exception agreed that the improvements were very clear. Our criterion for success was that we'd get higher frame rates on the agenda for consideration in future TV standards, and I think we certainly achieved that. We're looking into what to do next, including finding a way to display images at frame rates higher than 120fps (the upper limit of all the contemporary displays we're aware of* - we've been using projectors designed for alternating-frame stereoscopic 3D so far), investigating how increasing the frame rate of video improves the efficiency of video codecs, experimenting with changing the temporal shape of camera shutters (simulated by down-conversion from high frame rates to conventional ones), and verifying our assertion that shooting at higher frame rates doesn't increase the visible noise in the video signal. Problem is, we really want to do some more work on 3D television, too...

We've published a White Paper on our initial work, available here. It's quite short, contains no maths, and would interest (I hope) technically-minded people from both inside and outside broadcasting. Similarities between the historical section and this post need not be pointed out. :-)

*we have CRT monitors that can go up to 200fps, but not at any kind of sensible resolution.

EDIT: We made it into the "press"! Woo! :-)

19/04 The eyes have it

We installed infra-red cameras on top of every TV set. "Monitoring Audience Satisfaction" we called it. Eyes when turned towards the screen would blink white hot and the funding for each show increased in proportion to the number of viewers.

A year later and the effects on daytime telly filtered through. The evenings might be a glitterball parade of quiz shows and talent contests but the days - they were something else entirely. Courageous dogs saved little girls from burning buildings, tigers prowled the jungles indifferent and beautiful, somehow a stream of werewolf movies was scheduled during the school run.

It was an intern who finally pulled footage from the IR cams. Expecting to see the pinprick pupils of housewives and retired grandparents, she saw, instead wide friendly pupils - disproportionately large and canine - and rapt, vertical, feline slits.

That year The Island of Doctor Moreau beat all recorded viewing figures.

- Ariadne

10/03 3D Rugby

There was a reasonably widely-publicised live 3D broadcast of the rugby match between England and Scotland last Saturday, and there's a fairly non-technical writeup on the BBC News website. There's one particularly interesting quote:

"One of the first shots of the crowd showed a fan waving a large flag back and forth. It seemed to come right into the room and I had to resist the urge to reach out and touch it."

It's interesting, because I was present at the screening, and I swear that virtually all the shots were framed such that the action was (correctly) placed behind the screen in 3D space. Including the "flag-waving" one that the reporter particularly mentioned. Indeed, one of the few criticisms I'd make of the shot framing was that some shots had unavoidable foreground material (eg the pitch, or people sitting just in front of the camera in the stand) that were placed in front of the screen and were hard to converge because of their extreme disparity and proximity to the edge of the frame. I believe that the 3D team were understandably limited to camera positions not required for the simultaneous international 2D broadcast, and so they might have chosen differently given free reign.

A colleague who was present at the screening mentioned that the cameras were set a bit too far apart, resulting in a "Subbuteo" effect, whereby the players appeared to be a couple of inches high. He had a point, although looking at the "making of" videos linked to from that BBC News writeup, it becomes clear why; using broadcast-quality cameras and lenses and simple (aka foolproof) stereo mounting rigs, it simply wouldn't have been possible to get the cameras' optical axes closer together.

Another noteworthy point is instanced in the second of the three "making of" videos: lots of assumptions and working practices that apply to 2D television and film craft need rethinking when you're shooting stereo. The example here was rain - an annoyance when shooting sport in 2D, but entirely liveable with. In stereo 3D, any kind of blemish that is present only on one of the two camera images, such as raindrops on the lenses, is entirely unacceptable. And that's on top of ensuring that zoom, iris, focus, gain and all other camera parameters are kept synchronised on each camera in a pair - something that's far from trivial with current equipment.

Overall, it was a triumph for the Outside Broadcast team from BBC Resources, all the more so since they discovered to whom the BBC was selling their department on the day before the experiment: the sell-off being a process which is inevitably concerning them at present. I believe that their efforts have unambiguously demonstrated the feasibility of stereo 3D coverage of live sporting events, and hope that they (and we) can go on to develop a craft of 3D sporting coverage - perhaps one day even bringing it to the living room.