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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 29th Sep 2017, 5:16 pm   #1
ray4566
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Default DVD Source Material 1950s

Hello, I hope someone can help.

Background is I've just finished my first restoration of an Ekco TCG316 Radiogram/TV.

For my signal source I purchased a cheap Sony DVP-SR170 DVD player and an Aurora SCRF -405A 625/25i to 405/25i Converter.

All DVD's I have tested from my existing collection play OK but I really wanted to show the TV with some original 1950s/60s 4:3 programs so I purchased a Twilight Zone Season 1 DVD set from Ebay which is supposedly for region 2 (although there is nothing written on the sleeves that actually confirms the region).

All the discs from the set load OK and audio comes through but once playback starts the Aurora switches to test card output presumably because it is unhappy with the input video signal.

The discs in question play OK on my main Sony Blu Ray/Bravia TV combination and show their original 4:3 aspect ratio so from that I assume the disks are generally suitable for the UK market.

I 'scoped the Composite Video output from the DVD player and observed that the field interval was 16.7mSec from the problem DVD as opposed to 20mSec from the working DVD's so understand why the Aurora rejects it and conclude that the recorded format on the disc is 60hz as per the original US TV Source.

So the question is have I bumped into a generic problem that you more experienced renovators have frequently seen (in that DVD's of US originated TV shows for the UK market output at 60hz with the expectation that they will be used on modern flat screen TVs that can process the 60Hz field rate).

Or have I simply been sold a set of discs which were only intended for the US market ?

Or to put it another way are some of you already successfully playing US TV shows such as Beverly Hillbillies, Mr Ed, Lucy etc on your 405 Line TVs via DVD and Aurora.

Thanks in advance for any advice / pointers.

Ray
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Old 29th Sep 2017, 5:51 pm   #2
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Default Re: DVD Source Material 1950s

I think you're right and this is 60Hz video. The region coding has nothing to do with the technical standard of the data on the disc.
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Old 29th Sep 2017, 7:30 pm   #3
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Default Re: DVD Source Material 1950s

Thanks Paul,
This is the first time that I have needed to study DVD formats in more detail than just being a casual user.

After writing the original post I did find that some others on the forum have experienced the same problems (cannot re-find the thread though !).

So it's presently looking to me that these disks (published in 2011) were either:-

1/. Not intended for the UK Market and have come from abroad in which case they have been mis-sold (not too upset though as I only paid £10 and they will play on my main TV so I'll keep them).

or

2/. Intended for the UK Market on the assumption that consumers would (in 2011) be using a TV that can directly process and display 60Hz content or a player that will convert NTSC>PAL.

If it's 2/. I have naively thought that the content on the disk would have been converted to 625/50 PAL for our market.

Anyway, I think I can get hold of some Beverly Hillbillies DVD's that were definitely purchased from a UK shop so will re-test with those.
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Old 29th Sep 2017, 9:20 pm   #4
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Default Re: DVD Source Material 1950s

Check the menu settings of your DVD player, it's possible to force the video output from automatic to PAL or NTSC formats regardless of the disc content with some machines. Unfortunately this introduces an unpleasant frame dropping/video stutter effect when playing material not in it's original format.

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Old 29th Sep 2017, 9:46 pm   #5
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Default Re: DVD Source Material 1950s

You could use a PC running ffmpeg to re-encode the discs as a different frame rate .....
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Old 29th Sep 2017, 11:31 pm   #6
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Default Re: DVD Source Material 1950s

It's very unusual for DVDs to be standards converted for particular markets nowadays.

The region code just means that the DVD will only play in a player with the same region code, so a region 2 player will refuse to play a region 1 disc. This is quite separate from the data encoding on the disc. Nowadays the majority of DVD players either ignore the region code or can be configured to do so, so it's all a bit of a waste of time and effort. The system was introduced to allow Hollywood studios to control the release dates and pricing of movies in different markets, and to discourage grey imports.
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Old 29th Sep 2017, 11:39 pm   #7
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Default

Thanks for replies and suggested solutions so far.

The DVD player I am using is very basic and doesn’t have an NTSC > PAL conversion function in its menu (but a DVD recorder I’m looking at buying does have this, hope it also changes the field rate from 60 to 50hz) so that’s 1 thing to try.

I’ll also start looking at a PC based solution to make new DVDS as suggested by Julie if the NTSC > PAL conversion function doesn’t work well as previously pointed out.

I think the DVDs that I have are the genuine ones for the UK market since I noticed they have the BBFC ‘PG’ symbol on them and I believe (but admit I don’t know for sure) this is a UK only marking.

I may be guilty of over thinking this problem but I still cannot understand why DVDs from 2011 intended for the UK market would be outputting composite video at 60hz.

Hope someone can help me get my understanding right regarding whether this problem is expected and normal (or whether I have simply ended up with some disks that have counterfeit markings).

I now understand from your previous post Paul that the region coding is independent of the source format so am happy with that explanation.

And you replied whilst I was composing the post before this one.

Furthermore from what you say it sounds like (even in 2011) the manufacturers exporting DVDS of US TV shows to the UK were expecting consumers to already have TV’s capable of processing and displaying the 60hz material even though there may still have been a few CRT based 625/50 sets around.

I think I’m getting the point now, thank you .

Cheers & thanks again, Ray
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Old 29th Sep 2017, 11:59 pm   #8
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Default Re: DVD Source Material 1950s

Hi Ray, another approach is to coax one half of a dual-head computer graphics card into outputting a 405 line signal directly, all you then need is a modulator.

https://www.vintage-radio.net/forum/...d.php?t=130716
http://www.nostalgiatech.co.uk/Baird%20240%20lines.htm

Mods, I have asked before, could Peter's page above be made sticky?
This technique must be seen as a viable alternative to system-converting from 625.

Graham.
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Old 30th Sep 2017, 11:55 pm   #9
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Default Re: DVD Source Material 1950s

The TV programmes you mention-Twilight Zone etc were originally made on cine film and are therefore completely independent of any television standard. however they were obviously converted to something for DVD.

Why not make your own DVD?

Convert the VOBs on the offending DVD to MPEG2 using this simple and very good converter (free)

http://www.dvdvobtompg.com/

Once you have the MPEG2 convert back to appropriate DVD standard with something like Windows DVD Maker (free)
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Old 1st Oct 2017, 11:38 am   #10
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Default Re: DVD Source Material 1950s

Thanks to all who responded, I did end up converting, along the lines suggested by Julie & Charlie.

I found a program called Handbrake on my Laptop & used that to read in the 30FPS (60Hz) material from the source DVD's & generate MPEG4 files as output, specifying a frame rate of 25FPS.

I was also quite pleased that it allowed me to choose the output bit rate so that I could balance the trade-off between image quality and file size, and the fact that I could build a job queue to automate the process was also quite handy.

The end result was a Data DVD so no fancy Menus available but it suits my purposes and the SR-170 player was quite happy with the format.

It was magic watching 1959 material playing through the old 1957 TV.

The slight frame stutter mentioned by John did appear as expected, although I didn't find it a serious issue on this particular program material.


I also had a very interesting read of the information linked by Graham, quite fascinating learning some of the methods that people have devised.

thanks once again
Ray
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Old 1st Oct 2017, 9:41 pm   #11
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Default Re: DVD Source Material 1950s

The problem is with ciné film shot at 24 frames per second being shown at 30 frames, or 60 fields per second. You need to show 4 frames of film over 10 fields of TV. So the pattern goes: Scan odd lines of film frame 1 -- Scan even lines of film frame 1 -- Advance film and scan odd lines of film frame 2 -- Scan even lines of film frame 2 -- Scan odd lines of film frame 2 again -- Advance film and scan even lines of film frame 3 -- Scan odd lines of frame 3 -- Advance film and scan even lines of frame 4 -- Scan odd lines of frame 4 -- Scan even lines of frame 4.

Reducing this to from 30 fps to 25 fps by interpolation can make the errors caused by the two-field, three-field cycle appear worse. It would be better to obtain the original four frames of 24 fps film from ten fields of 30 fps video and output them -- in the correct order; bearing in mind field 3e actually comes in before field 3o -- over eight fields of 25fps video, but I don't know of any software actually doing this. If I was really desperate, I'd have a play with the Source Code to ffmpeg and try to cobble something together.

(In countries using 25 frames per second for TV, ciné film is simply sped up from 24 fps to 25 fps for television. This is barely noticeable except for increasing the pitch of the music by almost a semitone.)
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Old 1st Oct 2017, 10:39 pm   #12
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Default Re: DVD Source Material 1950s

Quote:
Originally Posted by ray4566 View Post
I may be guilty of over thinking this problem but I still cannot understand why DVDs from 2011 intended for the UK market would be outputting composite video at 60hz.
eBay is awash with counterfeit recordings and the reason I no longer sell DVDs or CDs.

If a title is available from eBay but not from a major retail source it is almost certainly counterfeit.
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Old 2nd Oct 2017, 1:36 am   #13
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Default Re: DVD Source Material 1950s

I've found this thread to be very interesting [despite not always fully understanding the content] but I do get the overall sense. This sort of techo archeology/recovery doesn't get enough recognition. I think I grasped most of what you said re cine film Julie. The semi-tone difference you mention though was not new to me. It was often said that only people with an acute sense of pitch would notice the difference-I certainly never did and clearly, it was never much of an issue for the Broadcasters or the viewers.

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Old 2nd Oct 2017, 9:38 am   #14
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Default Re: DVD Source Material 1950s

I've found it interesting too. I have very little dealing with DVDs and on the odd occasions I have I haven't been able to do anything other than play them on a computer (Windows or Linux) due to copy protection systems.
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Old 2nd Oct 2017, 11:48 am   #15
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Results FYI these pictures don't do justice, please excuse the strobe effect from phone camera and the frame top linearity which I'll fix another day.
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Old 2nd Oct 2017, 1:04 pm   #16
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Default Re: DVD Source Material 1950s

According to a 1970's edition of the "ITT Reference Data For Radio Engineers", in the US, the standard method of showing cine film on TV was to use a projector running at 24 fps fitted with a 5 blade shutter. This gave 120 flickers per second, and so each TV field (half frame) frame would consist of two sequential “flickers”. Thus the first two fields would consist of the same frame, while the third field would consist of the fifth flicker of the first cine frame and the first flicker of the second. With the persistence of the imagers then in use, the existence of a double exposed field would not be noticeable, and as the film ran at its normal sped, there was no change of pitch.

According to something I read in the "Amateur Photographer" at the time, a similar system in reverse was used by the BBC in the 1960's for recording TV onto cine film economically. Rather than running the camera at 25 FPS and recording only the odd (or even) TV fields (the technique used to record the Coronation), it was run at 16 2/3 fps with a pulldown period of 1/50 sec and a shutter speed of 1/100 sec. The film therefore recorded both fields of the first TV frame, the superimposed second field of the second frame and the first field of the third frame, then both fields of the fourth frame and so on. (They published an article on how someone had modified a 16mm sound projector to record TV with sound in this way. It worked, but of course the running cost was horrendous, around £1 a minute at 1960’s prices, when a working man's basic wage was around £10/week if he was lucky.)

For rebroadcast a projector with a three-blade shutter (not the 2 blade shutter normally fitted to sound projectors) running at 16 2/3 was used in conjunction with a conventional 25FPS imager/TV camera. I have a commercial VHS cassette of some 1960’s “Pinky and Perky” programmes that were obviously recorded by this method: stepping frame by frame shows the double exposure of every third frame, which consists of the two slightly different superposed images of what were originally fields of adjacent TV frames.

I use the same technique today for transferring silent 8mm cine film to DVD via a DV camcorder (when I can get one that is still in working order with its manual shutter speed function operational: a 1/50 sec shutter is essential) and the projector must run at as close to 16 2/3 sec as possible to completely eliminate flicker.

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Old 2nd Oct 2017, 1:25 pm   #17
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Default Re: DVD Source Material 1950s

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Originally Posted by julie_m View Post
(In countries using 25 frames per second for TV, ciné film is simply sped up from 24 fps to 25 fps for television. This is barely noticeable except for increasing the pitch of the music by almost a semitone.)
And presumably reducing the run time by 4%. Enough time to get a few adverts in!
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Old 2nd Oct 2017, 2:49 pm   #18
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Quote:
Originally Posted by julie_m View Post
(In countries using 25 frames per second for TV, ciné film is simply sped up from 24 fps to 25 fps for television. This is barely noticeable except for increasing the pitch of the music by almost a semitone!
Don't think that is the case in this century as the old CRT flying spot film scanners are long gone.
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Old 2nd Oct 2017, 7:29 pm   #19
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... taking some of the old operators along with them
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Old 2nd Oct 2017, 10:00 pm   #20
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Quote:
Originally Posted by ray4566 View Post
I may be guilty of over thinking this problem but I still cannot understand why DVDs from 2011 intended for the UK market would be outputting composite video at 60hz.
It's hardly any more complicated than: Because they could get away with it!

UK and European 625-line/25 fps TV sets, by happy accident, can usually lock directly onto a 525/30 signal with minimal picture distortion. Certainly, almost every set with a SCART socket (DVD players have no RF output) would have been able to display a picture from such a disc. And if the programme is in mono anyway, there's no need to worry about colour signals. (But DVD is natively RGB; the colour signal is generated during playback, so it can be made to any standard to suit the TV.)

Since US TV sets tended to be strictly single-standard, it made more sense to encode the DVDs to suit them and let the rest of the world make use of its multi-standards abilities.
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