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Post by garygraham on Nov 29, 2018 18:02:11 GMT
Why is the bluray of Department S encoded at 24 frames per second instead of 25fps as it would have appeared on TV in the past? I've double checked this tonight by ripping a small section and putting it alongside a capture from a 1990s VHS recording from BBC2. For example the title sequence is about three seconds longer on the bluray, which figures. Other Network discs such as The Professionals run at 25fps so I would love to know the reasoning behind this. For example does Network have evidence that Department S was shot at 24fps instead of 25fps? Also what about the original sound dubbing? Was the music dubbed at 24fps? So was it playing faster than recorded on TV in 1969 or is it playing more slowly now?
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RWels
Member
Posts: 2,857
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Post by RWels on Nov 29, 2018 20:49:13 GMT
Google suggests that it was shot on 35mm film, a format that in the cinema and in the USA runs at 24 fps. So it could either be a new mistake based on that; or a correction of a previously wrong speed.
Too bad you've blocked me, so you won't read this explanation!
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Post by garygraham on Nov 29, 2018 23:28:23 GMT
I've seen it I know that by the 70s some 16mm cameras could run at 25fps which is the speed film was shown at on British TV. Not sure what the situation was with 35mm and earlier than that. Oddly at 24fps the running time is between 50 and 51 minutes which I would say was the standard ITV slot with ads at the time?. But if you lose one frame per second by playing at 25fps that is 3000 frames over 50 minutes. Which is two minutes shorter at 25fps. Pied Piper of Hambledown runs for 50:29 at 24fps. Maybe they were shot at 24fps because Lew Grade had an eye on the US market?
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Post by Peter Stirling on Nov 29, 2018 23:38:15 GMT
Don't think you can judge anything from a 1990s recording..It was being transmitted from tape rather than film by then and anything could have happened in the transfer process from film to tape, - plus the fact technology was around to discretely speed it up or down to fit a certain time slot.
Although 16mm was shot at 24 or 25 fps ..35mm always retained it's world standard of 24fps...except when they experimented on some US progs of speeds of 30fps in order not have to invent the extra frames for NTSC TV
So the other possibility was that the 1990s recordings originated on 16mm
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Post by garygraham on Nov 30, 2018 1:01:46 GMT
It wasn't possible to stretch 24 frames per second to 25 without either duplicating one complete frame per second or mixing frames together. Neither of which is the case in the early 1990s recording. The frames are the same. I'm not even sure how "discretely" that could be done even now 25 years on using computer motion estimation.
If it's true that 35mm was never shot at 25fps then it was simply shot at 24fps and shown at 25fps on British television. In the same way Dallas and Star Trek were in the days when they were shown direct from film with the corresponding change in audio speed and pitch. I would be very surprised if British TV companies didn't have 35mm cameras which could run at 25fps to avoid that.
It's irrelevant whether the 1990s broadcast was 35mm or 16mm, either way it was broadcast at 25fps.
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Post by John Williams on Nov 30, 2018 9:10:19 GMT
ITC shows were shot at 24fps. There might be some exceptions but Network look at the documentation and encode appropriately.
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Post by Peter Stirling on Nov 30, 2018 10:03:12 GMT
It wasn't possible to stretch 24 frames per second to 25 without either duplicating one complete frame per second or mixing frames together. Neither of which is the case in the early 1990s recording. The frames are the same. I'm not even sure how "discretely" that could be done even now 25 years on using computer motion estimation. If it's true that 35mm was never shot at 25fps then it was simply shot at 24fps and shown at 25fps on British television. In the same way Dallas and Star Trek were in the days when they were shown direct from film with the corresponding change in audio speed and pitch. I would be very surprised if British TV companies didn't have 35mm cameras which could run at 25fps to avoid that. It's irrelevant whether the 1990s broadcast was 35mm or 16mm, either way it was broadcast at 25fps. It's also irrelevant what the frame rate was as 1990's tapes could run at different speeds and still retain their Pal system integrity.. even the failed Philips V2000 domestic format VCR ( introduced dynamic track following) would have been capable of a 'fit your time ' feature had it been successful. However it all gets rather complicated as I don't remember any pitch difference between say Star Trek in the 60/70s and the recent runs while it was prominent on Dallas - this bright and lively programme suddenly became a dark, fuggy and slurred atrocity and many people complained.
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Post by garygraham on Nov 30, 2018 13:12:21 GMT
But at the end of the day something was shot on film either at 24fps or 25fps. It could then be played at any speed. Any of which will alter the running time. However the PAL TV system has 50 fields per second and optimally film runs at 25fps. So you get one original frame every two fields. The integrity of the individual frames is retained.
At speeds which aren't a multiple of 25 you get blended frames or a pattern where some are repeated twice. It's only in recent years we've had computers that can create extra frames that never existed.
As for Star Trek it depends what they're doing. Quite possibly it still runs at 25fps in the UK with the pitch increase whereas in the US it will run at 24fps. However in the case of some sort of horrid conversion from US video - as broadcast on BBC2 in the mid-1990s the film will have run at 24fps and then the video converted with the aforementioned mixed frames but no pitch increase. These days they can correct the pitch of the audio if showing at 25fps. So the audio is the correct pitch even though it and the picture run 1/25th second faster than when it was filmed.
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Post by Richard Marple on Nov 30, 2018 13:41:37 GMT
I remember reading that Dallas switched to being distributed on NTSC video tape running at 30fps, which was then converted to 25fps PAL for broadcast by the BBC, but lost picture quality by being 2 generations from the source material shot on 35mm film at 25fps.
The Doctor Who Restoration Team had to do a few tweaks to Spearhead From Space for the Blu Ray to get the frame rate & sound to play right.
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Post by garygraham on Nov 30, 2018 18:56:58 GMT
I remember reading that Dallas switched to being distributed on NTSC video tape running at 30fps, which was then converted to 25fps PAL for broadcast by the BBC, but lost picture quality by being 2 generations from the source material shot on 35mm film at 25fps. The Doctor Who Restoration Team had to do a few tweaks to Spearhead From Space for the Blu Ray to get the frame rate & sound to play right. That's right. We sat down to watch the first episode of the new series. Instead of the glossy, pin sharp 35mm that we were used to there was this murky converted NTSC video. I think it happened with the 1986 series that begins with Bobby in the shower and the revelation that the entire previous series had been a dream. You can see the difference here. Maybe the BBC had no choice. But for a series that was in part based on being "glossy" it was a mistake. Then Star Trek suffered the same thing in the early 1990s. It continues today as some films shown by the BBC are a blurry standards conversion.
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Post by Peter Stirling on Dec 2, 2018 0:15:41 GMT
But at the end of the day something was shot on film either at 24fps or 25fps. It could then be played at any speed. Any of which will alter the running time. However the PAL TV system has 50 fields per second and optimally film runs at 25fps. So you get one original frame every two fields. The integrity of the individual frames is retained. At speeds which aren't a multiple of 25 you get blended frames or a pattern where some are repeated twice. It's only in recent years we've had computers that can create extra frames that never existed. As for Star Trek it depends what they're doing. Quite possibly it still runs at 25fps in the UK with the pitch increase whereas in the US it will run at 24fps. However in the case of some sort of horrid conversion from US video - as broadcast on BBC2 in the mid-1990s the film will have run at 24fps and then the video converted with the aforementioned mixed frames but no pitch increase. These days they can correct the pitch of the audio if showing at 25fps. So the audio is the correct pitch even though it and the picture run 1/25th second faster than when it was filmed. I was in the US in the 1980s and watched 'Lost in Space' a prog that had been off the air in the UK for some time so looked forward to it, IIRC the pitch sounded the same as the UK showings, but of course if the camera moved the picture juddered a bit due to making up those extra frames for the NTSC 60hz standard... it was also rather impossible to watch due all the flaming commercial breaks. Film had to run at 25fps on the old broadcasting flying spot telecines, but an image sensor or camera(instead of a flying spot tube) sees what is front of it and 'films' at whatever standard it is set at..old home movies ran at 16/18fps but when transferred to VHS they didn't have to be speeded up to 25fps.
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Post by garygraham on Dec 2, 2018 14:05:16 GMT
But at the end of the day something was shot on film either at 24fps or 25fps. It could then be played at any speed. Any of which will alter the running time. However the PAL TV system has 50 fields per second and optimally film runs at 25fps. So you get one original frame every two fields. The integrity of the individual frames is retained. At speeds which aren't a multiple of 25 you get blended frames or a pattern where some are repeated twice. It's only in recent years we've had computers that can create extra frames that never existed. As for Star Trek it depends what they're doing. Quite possibly it still runs at 25fps in the UK with the pitch increase whereas in the US it will run at 24fps. However in the case of some sort of horrid conversion from US video - as broadcast on BBC2 in the mid-1990s the film will have run at 24fps and then the video converted with the aforementioned mixed frames but no pitch increase. These days they can correct the pitch of the audio if showing at 25fps. So the audio is the correct pitch even though it and the picture run 1/25th second faster than when it was filmed. I was in the US in the 1980s and watched 'Lost in Space' a prog that had been off the air in the UK for some time so looked forward to it, IIRC the pitch sounded the same as the UK showings, but of course if the camera moved the picture juddered a bit due to making up those extra frames for the NTSC 60hz standard... it was also rather impossible to watch due all the flaming commercial breaks. Film had to run at 25fps on the old broadcasting flying spot telecines, but an image sensor or camera(instead of a flying spot tube) sees what is front of it and 'films' at whatever standard it is set at..old home movies ran at 16/18fps but when transferred to VHS they didn't have to be speeded up to 25fps. On the third frame grab from Dallas above (of the title) you can see that two film frames are visible on screen at once as the title zooms up. Presumably because it was shot at 24fps, then telecined for NTSC at 29.97fps then standards converted to PAL at 25fps (what a mess). Instead of the 24fps 35mm film simply being shown at the slightly increased rate of 25fps in the UK. Which would have kept the integrity of the film frames. When I transfer Super 8 that was shot at 18fps, I adjust the speed down to 16 2/3 frames to avoid strobing. That's because 16 2/3fps is one third of 50fps. When viewed, some frames are blended and it runs slightly slower that the original action did. There is no way that 18fps will ever fit into 25fps without combining or duplicating frames, or some form of computer motion prediction which creates intermediate frames that never existed. In the same way as 24 fps will never fit into 25fps without the same. You can run film at whatever speed you like and it may or may not be the speed it was originally shot at. But regardless, there will still be 25 frames/50 interlaced fields on a PAL TV. You could run the film at 1fps or 100fps but there will still be 25 frames/50 interlaced fields with film frames duplicated, blended, skipped or created by a computer.
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Post by Peter Stirling on Dec 4, 2018 0:50:22 GMT
You can run film at whatever speed you like and it may or may not be the speed it was originally shot at. But regardless, there will still be 25 frames/50 interlaced fields on a PAL TV. You could run the film at 1fps or 100fps but there will still be 25 frames/50 interlaced fields with film frames duplicated, blended, skipped or created by a computer. Well yes that basically is what I was saying apart from the need for any computer or modern equipment to make up frames- the image sensor (what ever it is) will be recording at the 25fps Pal standard and will record the picture from the film as more or less as you see it yourself..there is no need to slow it down or speed it up. 1980s VHS transfers from 8mm looked quite normal with no speed variations or perceptible different running times. Standard 8 films (running at 16 3/4 fps) _looked even better because as you say due to the maths of dividing quite nicely into the 50 fields...1980s VHS 18fps transfers had other problems such as flicker or strobing because the playing back medium and the recording medium were out of synchronisation with each other's shutters- or in electronic terms the blanking period on the vt recording and the mechanical shutter on the film medium. The flying spot telecine used to broadcast films for many years was essentially a TV CRT tube in reverse and two tubes were needed for the two television fields hence that was critical it ran at 25fps and in those days old hand cranked Charlie Chaplin etc films always looked speeded up. 8mm home movie films in those days were never shown on TV unless the budget included a conversion to 16mm and frames duplicated (as you said)to make up the extra frames. Covert programmes like 'World in Action' sometimes used 8mm cameras for size but these ran at 24fps..or maybe 25 fps? The 16mm telerecording film from the Pal source also ran at 25fps..I played one (don't worry nothing lost or important)on a standard projector (24fps) and the pitch was notably lower. Dallas was obviously different because it appears to have been a tape to tape conversion - they would have probably got better results if the had mastered it on Pal?
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Post by Richard Marple on Dec 4, 2018 13:01:23 GMT
There was a specialist telecine system with a rotating prism that worked better differing frame rates, but probably was an expensive bit of equipment to buy & operate.
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Post by garygraham on Dec 7, 2018 1:09:14 GMT
You can run film at whatever speed you like and it may or may not be the speed it was originally shot at. But regardless, there will still be 25 frames/50 interlaced fields on a PAL TV. You could run the film at 1fps or 100fps but there will still be 25 frames/50 interlaced fields with film frames duplicated, blended, skipped or created by a computer. Dallas was obviously different because it appears to have been a tape to tape conversion - they would have probably got better results if the had mastered it on Pal? I'm not sure what they did but those really ropey conversions seemed to have become a thing of the past by, I would say, the late 1990s? Once digital editing came along it would be possible to edit film at 24fps and then compile masters in different formats quite easily as you've suggested.
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