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Channel television network contributions

(January 2019)

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KE
kernow
Si-Co posted:
Steve in Pudsey posted:
ttt posted:

Possibly. My post may have been longer had I had to describe it, rather than use a phrase commonly understood by anoraks...


"Noddy" is the term everybody understands Smile


Wasn’t there a “Big Ears” too, another piece of kit? If that’s the case, I assume NODD/Noddy was an “official” nickname.

There was a toyland as well!
BL
bluecortina
deejay posted:
V-Fade and U-Fade are the usual terms these days but the BBC always used to call it a “Down and Up” (Originally when going between two slides in a junction, when they were physical slides in a scanner, this required a “Down, Change and Up” which was essentially a U-Fade)


We simply said ' .. and fade and take'.
BL
bluecortina
ttt posted:
deejay posted:
V-Fade and U-Fade are the usual terms these days but the BBC always used to call it a “Down and Up” (Originally when going between two slides in a junction, when they were physical slides in a scanner, this required a “Down, Change and Up” which was essentially a U-Fade)


Sorry to go off-topic but when would a V-fade become a U-fade?

An electronically-generated down-and-up would of course always be a V-fade since generally there are only 0 or 1 frames of actual black.

Older manual ones would technically always be U-fades -- with an underscanning TV you could see this in action on some channels where you'd sometimes see that a small portion of the left-hand edge of the A source being faded out would remain at full intensity then that sliver of image would cut to the B source, which would then be faded up.

Or are you saying that a U fade would be where the actual slides would be shifted to the next one whilst the screen was black? Wasn't it the case that they'd have two scanners and cut between them?

I guess the NODD system would need a U fade if changing between the clock and globe for example on the BBC.


As I knew it:
V-fade. Fade first source down to black, fade up second source.
U-fade. Fade down first source, wait, fade up second source.
Fade and take = V-fade.

Your mention of seeing a small amount of video on the lhs of the screen points to a fault on the mixer, or more likely misalignment. It would be known as a 'blanking error'.

Slides. All the Rank Cintel slide scanners I worked on or knew about had two 'ports'. Ports means that the scanner had two independent channels and that you could switch (internally to the slide scanner) between the two ports (slides). Thus you can do a slide cutting sequence one after the other within one machine. These were extremely common machines within ITV and the BBC. I do not know if Channel TV had one.
NG
noggin Founding member
bluecortina posted:
ttt posted:
deejay posted:
V-Fade and U-Fade are the usual terms these days but the BBC always used to call it a “Down and Up” (Originally when going between two slides in a junction, when they were physical slides in a scanner, this required a “Down, Change and Up” which was essentially a U-Fade)


Sorry to go off-topic but when would a V-fade become a U-fade?

An electronically-generated down-and-up would of course always be a V-fade since generally there are only 0 or 1 frames of actual black.

Older manual ones would technically always be U-fades -- with an underscanning TV you could see this in action on some channels where you'd sometimes see that a small portion of the left-hand edge of the A source being faded out would remain at full intensity then that sliver of image would cut to the B source, which would then be faded up.

Or are you saying that a U fade would be where the actual slides would be shifted to the next one whilst the screen was black? Wasn't it the case that they'd have two scanners and cut between them?

I guess the NODD system would need a U fade if changing between the clock and globe for example on the BBC.


As I knew it:
V-fade. Fade first source down to black, fade up second source.
U-fade. Fade down first source, wait, fade up second source.
Fade and take = V-fade.


Agree with V-fade and U-fade - which are both 'down and ups' but the U-fade spends longer in black.

However a 'fade and take' was a fade-to-black followed by a cut to video (not a fade up)

I tried to draw them as ASCII art but the forum software filters out backslashes it seems.
TE
Technologist
noggin posted:
Inspector Sands posted:

There's also a U transition, which has a longer period of black. Useful when some sort of external switching like an aspect ratio change is needed to be hidden. In the early days of digital TV the BBC used a 12 frame U transition in and out of every 4:3 programme on their digital networks, this in theory gave set top boxes and their own ARCs enough time to subtley change ratio in the black


Yes. This was only needed for DSat (because Sky boxes don't/didn't support AFDs), which used ARCs + MPEG2 aspect ratio switching (which only changed on a GOP boundary) between 16F16 and 12F12 encoding. As this isn't frame accurate, the 'U' helped hide the switch (though you'd still see sometimes see stretched/squashed video sometimes)

BBC DTT used AFDs and a constant 16F:9 signal that either carried 16F16 or 12P16 content (which I think was the format 4:3 was ingested in) - and thus no GOP-based MPEG2 header switching and asa result you got frame accurate aspect switching on a 4:3 display (as the receiver was doing the centre-cut, under AFD control, not the broadcaster upstream of the MPEG2 encoder)


Also the BBC was using decoders in the regions which did not handle AFDs
So the AFD was signalled in teletext in the subtitle headers ....
Thus added another field or so of uncertainly so the U was 1frame longer than it absolutely needed to be but there was not a "picture bounce" as Uktv had until just a few years ago ..
but Pam Masters H BBC Presentation did not like the "extra" black ....
But TV sets did behave very differently,
BL
bluecortina
noggin posted:
bluecortina posted:
ttt posted:

Sorry to go off-topic but when would a V-fade become a U-fade?

An electronically-generated down-and-up would of course always be a V-fade since generally there are only 0 or 1 frames of actual black.

Older manual ones would technically always be U-fades -- with an underscanning TV you could see this in action on some channels where you'd sometimes see that a small portion of the left-hand edge of the A source being faded out would remain at full intensity then that sliver of image would cut to the B source, which would then be faded up.

Or are you saying that a U fade would be where the actual slides would be shifted to the next one whilst the screen was black? Wasn't it the case that they'd have two scanners and cut between them?

I guess the NODD system would need a U fade if changing between the clock and globe for example on the BBC.


As I knew it:
V-fade. Fade first source down to black, fade up second source.
U-fade. Fade down first source, wait, fade up second source.
Fade and take = V-fade.


Agree with V-fade and U-fade - which are both 'down and ups' but the U-fade spends longer in black.

However a 'fade and take' was a fade-to-black followed by a cut to video (not a fade up)

I tried to draw them as ASCII art but the forum software filters out backslashes it seems.


Where I worked a ‘fade and take’ was as I described (1970’s). If the incoming video started with a frame of non-black video it would look on air as you described but it was not ‘engineered’ to look like that. This was all before automated pres systems. Different companies, so likely different nomenclature I expect designed around the kit they had at the time? I have seen modern mixers with the built in transition as you describe, but I did not work with them personally.
RO
robertclark125
Colour TV didn't reach the channel islands until 1976. So, during the period when it was black and white, what test card did Channel TV radiate from the transmitter, if any?
MA
Markymark
robertclark125 posted:
Colour TV didn't reach the channel islands until 1976. So, during the period when it was black and white, what test card did Channel TV radiate from the transmitter, if any?


Good question !

It was the IBA's job to radiate test cards, and in the 50/60s/70s they had a control room at each main regional (and sub regional) transmitter to do that. Fremont Point was no exception, it's a large building there, (that the BBC built a small pres studio in the garage of, for Jersey TV news opt Mk1) The IBA had a number of permanent staff there I think. So 1960s it would have been Test Card D

http://www.murphy-radio.co.uk/gallery/tcd/croydon.gif

In theory that may have lasted until 1976, but I suspect they rebroadcast Stockland's Hill test card when Westward were not showing progs either (that post 1971 would have been TCF ?) However, filling the gaps when WW were on, but CTV were not, I don't know ?
SP
Steve in Pudsey
Si-Co posted:
Steve in Pudsey posted:
ttt posted:

Possibly. My post may have been longer had I had to describe it, rather than use a phrase commonly understood by anoraks...


"Noddy" is the term everybody understands Smile


Wasn’t there a “Big Ears” too, another piece of kit? If that’s the case, I assume NODD/Noddy was an “official” nickname.

Twin magazine slide scanner, as I recall.
EL
elmarko
I think I’ve mentioned this before, but my mate worked at Channel for a while and still freelances for them occasionally now doing cameras on lives and packages for Channel Report. If anyone has any questions I can pass some on.

Especially “what was it like to be Oscar Puffin?”...

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