noggin's posts, page 306

Crimewatch with Jeremy Vine and Tina Daheley

Looks like a 4 week run in September, rather than a year round series, with another block next year?

Picture Dropout on Video Causes

Drop-out is usually caused by either tape getting older (the 'glue' that keeps the oxide or similar metallic stuff on the plastic tape backing goes off and ceases to work as well) or being damaged through over-use/re-use (video tape relies on a physical contact between the tape and a large spinning metal head...) Poor alignment of the heads could also damage tape. This is permanent drop-out, but as the tape degrades particles flake off, and these can also 'clog' the replay heads, causing a drop-out on the replay (even where the recording is fine)

Decent analogue VTRs have 'drop out compensators' which detect the loss of RF and have a line-delay (so can replace the missing video with content from the line before) which will hide minor drop-out, but major drop out across multiple lines can be made very visible (as you get multiple lines of repeated video). This was particularly common on knackered Beta SP...

Digital tape recording formats like D3, D2 and DigiBeta have far better error correction and then error concealment systems which made digital VTRs a lot more robust. DigiBeta could cope with significant head clog ISTR without looking terrible. DVTRs also were able to warn you that they were getting errors - which could be useful warning to clean your heads etc.

You also see head-switching errors on Quad 2" and B-format 1" recordings (C-format 1" recorded an entire field in one track, whereas B-format used multiple tracks so had head switching) These head switching errors are far more obvious though, as they are regular dots or tears in a relatively fixed position.

BBC Olympic Breakfast

The ground floor spaces in the BBC Salford space now used by BBC Sport News had a number of intended occupants (which changed iteratively) during the design process I understand...

Olympics 2016

I think this is also the first time since Atlanta in 1996 that the main Olympics Summer Games host coverage has been produced in 1080/59.94i - the US HDTV standard. The 2000, 2004, 2008 and 2012 games were all produced in 576/50i or 1080/50i as they were in 50Hz territories, so US viewers had to watch a standards converted picture. This year you'll get the stuff unmolested (Well technically at least - I'm sure NBC will cut it to ribbons as usual...)

PALplus

It's important not to confuse widescreen production (and 16:9 deep letterbox broadcast on 4:3 outlets) with PALPlus. It wasn't just a name for letterboxed content - it had more to it than that.

PAL Plus was a modified broadcast system that 'hid' extra picture detail in the black bars above and below the letterboxed picture that regular viewers saw, to allow the vertical resolution of the 432 lines of the letterbox picture to be improved a bit. (The black bars contained additional picture information encoded by modulating a chroma subcarrier, but at black level. These weren't visible on a properly lined up set, but if you had the brightness turned up you could see a faint blue pattern in the black bars ISTR)

The PAL Plus system also included some improvements to the PAL decoder, that were assisted by the broadcaster flagging whether the content was originally 25p (no motion between the two fields in a frame) or 50i (motion between the two fields) - which were called FILM and VIDEO I think - as the PAL decoder in the PAL Plus TV could alter modes based on this information (to improve the chroma decoding on films). This data was flagged in the Line 23 WSS signal - which ISTR Channel Four continued to use for 16:9/4:3 signalling even after they stopped using PALPlus encoding for the actual video content.

Line 23 WSS continued to be used by STBs (not Sky's though) to signal aspect ratio of SD outputs ISTR. (The early Tivos sold in the UK also handled Line 23 WSS well)

The BBC couldn't easily use PAL plus because of the way their network was distributed - which may have been one reason it never really took off here. Sony also sold sets with PAL Plus decoders - one of their very high end 16:9 CRT sets that had 1250 line DRC processing included it. (This was effectively an HDTV without any means of getting an HD signal into it - without modification - which was a real shame)

What's also interesting is that of some of the first 16:9 CRTs I first remember seeing - two were made by companies now unheard of in the TV marketplace (Thomson/Ferguson and Nokia). The reality was that most 16:9 sets in the UK were really sold for people to watch Laserdisc and VHS tapes of letterboxed movies (though ISTR that some full resolution anamorphic 16:9 laserdiscs were also released)

If BSB had taken off there would have been full resolution anamorphic TV to watch far earlier than this as their DMAC system allowed for 16:9 anamorphic broadcast - and in Scandinavia TV1000 were showing 16:9 anamorphic movie transfers around this time (they used BSkyB's 16:9 telecine they inherited from BSB ISTR, or was it Channel Four's?) as they were using D2MAC which allowed for 16:9 full resolution broadcasts.

First full resolution 16:9 stuff I watched at home was the 1992 Albertville Olympics HDTV broadcasts, which were broadcast on TDF1 and TV Sat using HD-MAC, which a modified BSB receiver and Squariel could receive. I scan crushed a 14" 4:3 CRT to get them to letterbox though...

Olympics 2016

Also worth remembering that BT Sport don't operate the studios and facilities that they use in Stratford themselves, they hire in the facilities from Timeline, who also provide the same facilities to other broadcasters - like the BBC.

So a picture taken of a gallery stack in Stratford that BT Sport use regularly doesn't mean that BT Sport are using it that day.

Not suggesting that this is the case in this case, but an important difference to remember when thinking how BT Sport operate compared to Sky Sports, for instance (Sky own and operate their own facilities)

BBC told to do more for colour blind people

Yep - and they are contrary to BBC Producer Guidelines - which make it clear that this should only be done in exceptional circumstances. It's also why foreign speech in news reports should be dubbed not subtitled, unless absolutely necessary, and in that case the contents of the subtitled content should be signposted in commentary before or after so that the overall report still makes sense.

Just as bad - lots of those BBC World News backgrounders used to have text that was outside 16:9 graphics safe, let alone 14:9... Which is a pity as lots of BBC World News viewers (North American outlets I believe is one case in point) get a 4:3 SD feed which is 14:9 letterboxed...

Olympics 2016

Yes - you'd have thought OBS would have clipped it up a bit more cleanly for YouTube. Not a surprise that the original circuit had a slate appear after the show had finished though. You wouldn't want to leave black on a circuit - so having an ID slate makes a lot of sense (and audio so you know it's a live feed and not a freeze in the IRD)

BBC World News from New Broadcasting House

Not sure where that Urban Myth sprang from - both voices on the BBC TVC implementation of Columbus - the playout system that generated Digital Dorothy's voice - were recorded by Omnibus Systems staff.

There was a short-lived voice that ran until Christmas 1997, which was then replaced (because it was so terribly depressing) with a new recording from the same person (I think). Certainly the long-standing 'Digital Dorothy' voice that ran post-Christmas 1997 until Columbus was retired was the voice of someone who worked at Omnibus (I think the receptionist).

Very spooky to meet her in the flesh... Apparently everyone asked her to count backwards...

(She wasn't called Dorothy ISTR, and she wasn't a PA)

News Control, which was the other Omnibus system used for playout in BBC News, used to trigger Bigted for timings and caption automation, so when that playout system was being used, Digital Fiona (aka Fiona Bruce's voice from Bigted) was heard. Slightly spooky when Fiona was presenting. (Particularly the strident 'STANDBY TIGHT ASTON - TIGHT ASTON NOW')

Robot Wars is coming back!

Guess that might depend on the original frame rate and the required slow down. High speed cameras (as opposed to SuperSlowMo) usually record natively progressive, so if you shoot 100fps and run this at 50i you will get 1/2 speed, but if you run it at 25p you'll get 1/4 speed. (Though suspect this is people not really caring about fluid motion...)

Emergency Broadcasts

Yep - RDS may have offered similar functionality, but it never really arrived or was implemented well on portable sets (it was really a car thing - as I suspect few people bought separate FM tuners for their HiFi with RDS, and how many people connect the aerials to their AVRs when the same stations are on DSat or DTT?)

Kitchen DAB radios have nice alphanumeric displays showing the station name, making it easy to find the station you want, the equivalent FM sets usually just had an analogue dial or digital frequency readout with no station name, radio text etc.


Yep - all my listening locations are well covered by DAB. Sure the sound quality isn't great - but for kitchen radio listening on a mono speaker it's good enough. If I listen in quality on my decent amp in the living room, then the 320k AAC stuff is better than FM IMO.


Yep - FM has never been brilliant in London - DAB is less prone to break up and interference in my experience (and no major pirate issues yet...)



Yep - snap.

The other big advantage of DAB is the SFNs - so that you don't have to retune national services wherever you are in the UK, as they are on single frequency networks - no need to retune (even in the background)

Eurovision 2017

So chosing a venue close to Russia may be seen as concentrating attention on the region for at least a little while - may be a politically advantageous move by the Ukraine team?

If Dnipro was annouvned as the host city, and then fell to Russian/Russian-backed forces? Not a great PR coup for Putin...