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TV Breakdown Appreciation Thread

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MA
Markymark
WMD posted:
Si-Co posted:
I know Coronation Street often had daytime repeats during the 90s and early 00s, I don't recall Emmerdale ever having any though.


From September 1993 until the late 90s, Emmerdale received an early afternoon repeat (in a slot shared with Coronation Street repeats on the other days) - this was sometime between 12.55 and 3.20 depending on the region.

These 1990 episodes wouldn’t have been repeated until Granada Plus repeated them in the 00s though. I wondered if that episode was from this repeat run, but it’s been confirmed otherwise. Interesting that TVS used unbranded slides during breakdowns for the benefit of Channel TV - I assume Channel may have used their own slides and announcers during some breakdowns, but if they weren’t quick enough, the generic apology went out.


TVS had an unbranded clock too. This was routinely used at 05:59:50 into TVam, and was voiced as ‘ITV for South and South East England and the Channel Islands’. Saved an early shift for someone in St Helier!


When I visited the CIs in the 90s, CTV did seem to manage on most 'national' breaks to blank out the Meridian break bumper !
BL
bluecortina

Point of order, not SMPTE bars, ITV/4 used EBU 75% bars for line up I think?, (The Beeb 95% EBU?)


In all my years within ITV I never saw anything other than 100.0.100.0 colour bars used on a routine basis. Perhaps sometimes radio links might have used lower saturation bars to test a link. The fact that a transmitter could not routinely handle ‘full’ bars was not of any real concern to the contractors as it was not their area of responsibility and they never expected to transmit fully saturated bars. Naturally we had other colour bar test signals available but they were not used routinely.

I note on the linked site that no mention is made of the difference in bandwidth of the I and Q signals, but I have it in the back of my mind somewhere that this was practically ignored and may indeed have been phased out as time went by. Obviously that wouldn’t have affected the signal amplitudes of RGB which is the point under discussion here of course.


I & Q was really only relevant to NTSC - and although a nice optimisation, the reality was that the different bandwidths weren't exploited, and both I & Q components were handled at the lower bandwidth AIUI. I think modern NTSC coders and decoders are 'equiband' and code and decode in the U and V domain and handle the phase shift?


I’m pretty sure the bandwidth differences in I and Q were dropped for all intents and purposes as the years went by. My personal experiences with NTSC was in standards conversion etc, NTSC was a lot ‘better’ than people give it credit for, based usually on domestic pictures.
NG
noggin Founding member

I’m pretty sure the bandwidth differences in I and Q were dropped for all intents and purposes as the years went by. My personal experiences with NTSC was in standards conversion etc, NTSC was a lot ‘better’ than people give it credit for, based usually on domestic pictures.


Yes - the extra costs involved in non-equiband coding meant it was never really deployed AIUI (both in coders and decoders). NTSC is fine in controlled studio environments, but the lack of any phase correction (and thus hue errors) does mean that once it's being distributed on analogue cable networks and broadcast terrestrially, it degrades more quickly and even small phase/hue errors are really noticeable to the eye.

PAL is more robust, and can be decoded more cleanly these days (the 8-field sequence allows for some clever maths to almost completely eliminate cross-colour/cross-luma)

SECAM was the most robust chroma format (the FM modulation is bomb-proof, and using vertical sub-sampling makes its life easier) - but the compromises involved mean it has a very distinctive 'look', and practical studio implementation was a nightmare (you can't mix SECAM signals in the way you can PAL or NTSC, and keying also causes some nasty artefacts if not done properly)
BL
bluecortina

Point of order, not SMPTE bars, ITV/4 used EBU 75% bars for line up I think?, (The Beeb 95% EBU?)


In all my years within ITV I never saw anything other than 100.0.100.0 colour bars used on a routine basis. Perhaps sometimes radio links might have used lower saturation bars to test a link. The fact that a transmitter could not routinely handle ‘full’ bars was not of any real concern to the contractors as it was not their area of responsibility and they never expected to transmit fully saturated bars. Naturally we had other colour bar test signals available but they were not used routinely.



Thanks for the clarification. In the 80s I'd often be setting up cameras for both ITV companies and the Beeb, something in the back of my mind was a difference between colour bar set up? We had to adjust BBC stuff to a different standard. ITV was the same as European broadcasters (Yes, I know the BBC gamma curve was different)

I can't get my hands on my IBA COP document at present, but that was the bible we had to refer to for any ITV/ITN stuff



Point of order, not SMPTE bars, ITV/4 used EBU 75% bars for line up I think?, (The Beeb 95% EBU?)


In all my years within ITV I never saw anything other than 100.0.100.0 colour bars used on a routine basis. Perhaps sometimes radio links might have used lower saturation bars to test a link. The fact that a transmitter could not routinely handle ‘full’ bars was not of any real concern to the contractors as it was not their area of responsibility and they never expected to transmit fully saturated bars. Naturally we had other colour bar test signals available but they were not used routinely.



Thanks for the clarification. In the 80s I'd often be setting up cameras for both ITV companies and the Beeb, something in the back of my mind was a difference between colour bar set up? We had to adjust BBC stuff to a different standard. ITV was the same as European broadcasters (Yes, I know the BBC gamma curve was different)

I can't get my hands on my IBA COP document at present, but that was the bible we had to refer to for any ITV/ITN stuff


We used to routinely set cameras up using the BBC test chart that had the Gregory (super black) hole in it. Google reveals test chart 61 which is similar but not quite the one we used. It was the ‘classic’ card to set up camera gamma and since it was obviously a BBC card I would assume the BBC itself used it so I can’t quite see how the BBC and ourselves would end up with different gammas? Perhaps you are thinking of camera matrixing? Where I worked we did use the EBU values rather than the BBC’s values as they were considered more pleasing to the eye.

The IBA COP document was the standard to which the IBA required technical equipment to be held to, but where I worked we used the ITCA COP which was generally ‘tighter’ in most respects.
BL
bluecortina

I’m pretty sure the bandwidth differences in I and Q were dropped for all intents and purposes as the years went by. My personal experiences with NTSC was in standards conversion etc, NTSC was a lot ‘better’ than people give it credit for, based usually on domestic pictures.


.... Yes - the extra costs involved in non-equiband coding meant it was never really deployed AIUI (both in coders and decoders). NTSC is fine in controlled studio environments, but the lack of any phase correction (and thus hue errors) does mean that once it's being distributed on analogue cable networks and broadcast terrestrially, it degrades more quickly and even small phase/hue errors are really noticeable to the eye.

....


RCA were well aware of the advantages of phase alternation when developing NTSC but they considered the extra complication in receivers to be too expensive - we are of course talking about the early 50’s before the invention of the transistor etc! I read a detailed technical paper about their experiments with phase alternation at the time but I’ll be blowed if I can find it now despite much Googling over the years. Dr Bruch was maybe not so clever after all.
NG
noggin Founding member

I’m pretty sure the bandwidth differences in I and Q were dropped for all intents and purposes as the years went by. My personal experiences with NTSC was in standards conversion etc, NTSC was a lot ‘better’ than people give it credit for, based usually on domestic pictures.


.... Yes - the extra costs involved in non-equiband coding meant it was never really deployed AIUI (both in coders and decoders). NTSC is fine in controlled studio environments, but the lack of any phase correction (and thus hue errors) does mean that once it's being distributed on analogue cable networks and broadcast terrestrially, it degrades more quickly and even small phase/hue errors are really noticeable to the eye.

....


RCA were well aware of the advantages of phase alternation when developing NTSC but they considered the extra complication in receivers to be too expensive - we are of course talking about the early 50’s before the invention of the transistor etc! I read a detailed technical paper about their experiments with phase alternation at the time but I’ll be blowed if I can find it now despite much Googling over the years. Dr Bruch was maybe not so clever after all.


Oh - the past is a different country! There were all sorts of other chroma systems looked at in the 50s and 60s. The Russians came up with a version of SECAM not that different to PAL, and then there were proposals to have dual standard TVs (after all the UK and France had already done this) to allow for 50Hz and 59.94/60Hz content to be broadcast at native frame rate (frame rate conversion was still 'point a camera at a long-persistence phosphor telly' style and not very good) The plan was to have a single subcarrier frequency (not-ideal) for two different line/field standards - and transcode the chroma from NTSC 3.58 to a higher subcarrier frequency that would also be used for 50Hz broadcasts. The Dutch (presumably Philips/Norelco influence was strong) were major proponents of this approach AIUI.
MA
markwrightrf
Aside from all of the kerfuffle around the strike and Great Storm, are there any examples of TV-am breakdowns extant? I can't remember seeing a holding slide during a failed break or pre-recorded programme falling off air. Presumably, the gallery would alert whoever was on the sofa to fill?

EDITED TO ADD: Yikes! Don't attempt to search TV-am Breakdown at the usual place as you'll be greeted by the most horrendously inept mock posted by a certain Mr C.W. (not Cholmondley Warner). Shiver.
Last edited by markwrightrf on 24 September 2019 5:46pm
WH
Whataday Founding member
They used to have a holding slide in the early days when they didn't have enough adverts to fill the breaks.
SC
Si-Co
They used to have a holding slide in the early days when they didn't have enough adverts to fill the breaks.


Really? I don’t recall seeing that. Were TVam’s breaks national or did they follow a LEMNUS-type model?
WH
what
Si-Co posted:
They used to have a holding slide in the early days when they didn't have enough adverts to fill the breaks.


Really? I don’t recall seeing that. Were TVam’s breaks national or did they follow a LEMNUS-type model?

They had ad regions AIUI, although for some reason they were different to the ITV regional areas. The lack of ads in the early days was due to a number of factors, predominantly the fact they hadn’t reached an agreement with the actors’ union Equity.
RO
robertclark125
There were a couple of occasions when, on GMTV, the regional news opt out failed, and it reverted to the default GMTV slide with music.
MA
Markymark
Si-Co posted:
They used to have a holding slide in the early days when they didn't have enough adverts to fill the breaks.


Really? I don’t recall seeing that. Were TVam’s breaks national or did they follow a LEMNUS-type model?


LEMNUS style, but the northern regional ads were played out from Knutsford

Three regions from Camden, the other three from Knutsford I think

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