OT Television Production

[Chris J Dixon]

It was pretty impressive overall, though in live TV, when the images have a glitch in the tracking, there is not much you can do about it.

I remember one AR shot that didn't look as though it had tracked quite right, and I was able to compare with the dance-off when it worked correctly.

Very occasionally in the shots showing rehearsal scenes, or other background stuff, you get a glimpse of the line-up images used to set up the graphics.

I think "Click" showcased some of the technology in a recent programme.

Chris

[Chris J Dixon]

I believe on traditional film, the sound signal is displaced from the image, as it needs to run smoothly whilst the image jerks through the gate.

Is it the case that a well-chosen film splice could have just the effect described?

Chris

[Caecilius]

I think it's mainly an artistic technique that's been around since the first sound movies. Some history here:

I guess there could have been a technical reason as well, but I've never heard of that explanation.

[Michael Chare]

Sometimes the expected line of a shot on a snooker table are shown on TV. It is fun to see how good the prediction and the shot are.

[charles]

Since the early 1960s film runs smoothly thhrough the gate. The light source is pulsed on. Couldn't do that with carbon arcs, but they are no longer used.

[Dave Plowman (News]

That would be more of a repair than edit. In the pro field, sound and pictures have always been able to edit separately. Except, perhaps, the early days of videotape.

[Dave Plowman (News]

Generally, the last thing you want is the picture cutting before the sound, on a scene transition.

[Steve Walker]

Probably still had the sound and vision displaced though, to allow old and new films to play interchangeably on old and new projectors.

[The Natural Philosopher]

I am not sure, but I THOUGHT that the replay head moved along with the film, in jerks...

[JohnP]

The sound head is a distance away from the fim gate and the head is where the film is moving steadily through a capstan. There is a loop in the film to absorb the jerking.

[The Natural Philosopher]

Ah yes! I remember now! was back in the 1960s last time I played with cine film

[JNugent]

Fascinating!

It's something that most of us have obviously noticed over the years, but having it explained so clearly is excellent.

[JNugent]

As I understand it, editing of videotaped material has always involved copying, rather than physical cutting and assembly.

The reason for this was brought home to me over forty years ago, the first time I had a VHS cassette tape snap. I located the break, cleaned up the new mating surfaces and made a new joint with several pieces of

1/4" audio splicing tape (something I'd previously been doing with audio-tape, obviously).

It wasn't a physically bad job, considering the extra width of the recording tape and the limited width of the slicing tape, but the cassette was unusable because of the signal broke down when it got to that point. This was when E180s cost £17.95 each...

[charles]

2" video tape was initially cut for editing.

[Dave Plowman (News]

Not so, although electronic editing (copying to another tape) was the norm. But you could do it with a razor blade. Involved 'developing' the tape with magnetic powder so you could see the pulses. But tape was very expensive and cutting it made it no longer re-usable, so not used a great deal except in a sort of emergency.

[NY]

Cutting of tape was only possible with the early Quadruplex ("Quad") format where portions of the picture were recorded as successive tracks almost at right angles to the tape, and a tape cut/splice was possible as long as it was made in the gap between tracks, aided by magnetic "developing fluid" which made the control pulses visible so it was possible to see the frame sync pulses to join like with like. The crucial advantage of Quad was that the cut could be *guaranteed* to occur on a part of the tape between one video track and the next, which the flying head would not touch. But as you say, if you tried to re-use the tape, erasing the existing "electronic sprocket holes", it is likely that the splices would then occur during a track. At best this would cause a dropout in the picture and at worst the loose oxide at the splice could clog the video heads.

Quad lasted for live events such as football matches, when highlights needed to be compiled, even after it had been superseded in most fields by helical formats on reel-to-reel or cassette, because splicing tape allowed segments to be joined very quickly, without the need to dub them which would take at least as long as the length of the compilation that you were creating.

[Dave Plowman (News]

Yes - I've watched it being done on sport. The edit block includes a microscope to view the control track more easily.

I also remember it being used on a 'That's Life' where it was recorded not long before TX for legal reasons. And a mistake made. Choice, because of time, was a razor blade edit or do it again live. Went to the viewing room and watched it go out - there was a slight colour disturbance on the edit.

Those used to non linear digital editing don't know how lucky they are. ;-)

[Mark Carver]

For the rotating heads to hit a join, (or even crease) in the tape, (considering the angular etc forces involved) was a huge mechanical shock, that would shorten their lives.

Another reason the practice of physical VT editing in the 60s and 70s was used 'sparingly' by the TV broadcasters

[Dave Plowman (News]

Perhaps the main reason was the cost of the tape, then scrap if cut. In the early days of TV things were only archived if thought of later use. Nobody guessed there'd be so many channels that would show near anything.

Thames TV used to keep everything. Someone there had an eye on the future. But even there we used to re-cycle 2" audio tapes used for dubbing and music recording (after careful thought) Even some 1/4" too.

[John Walliker]

BBC Research Dept produced a progressive scan digital telecine machine in the early 1970s which moved the film in a continuous motion everywhere. There was a CCD line sensor feeding a digital field store to generate an interlaced signal.

John