405 to 625 converter?

[FrankT]

Hi all,

I read a lot about standard converters from 625 to 405 lines. However, are there also converters from 405 to 625? So I can in an electronic way recover old 405 line recordings.

Cheers
Frank

[Kat Manton]

Hi,

Give me a little time on this; I'll eventually be working on reprogramming a PC TV capture card, such that 405-line and doubtless other standards can be captured, recorded, converted to whatever standard you like, streamed over the 'net...

I've already worked out what I need to do, I've just not done it yet...

Regards, Kat

[FrankT]

Great Kat,

And I was thinking I would ask a silly question…..

[Kat Manton]

Hi Frank,

No, definitely not a silly question.

I've worked out what to do and how to do it; it involves a bit more work than generating obsolete standards. For a start I'll have to modify/write some software for once.

It's for this next line of experiments that I've been looking for either 405-line cameras or 625-line cameras which I can modify for 405.

After looking at this earlier this year, I think I could capture 405-line NTSC colour as well; it's not much extra once the capture card timings have been reprogrammed. Bet there aren't many colour 405-line recordings around, though...

Regards, Kat

[Panrock]

I'd be interested in this capability too Kat.

I've got a fair few old archive recordings on 405 VHS which I'd like to transfer to 625 DVD for conformity with the rest of my collection, I'd then convert material to 405 only while being viewed.

Steve

[Kat Manton]

Hi Steve,

I thought there'd be some interest in this, as I know there are a fair few 405-line recordings in private hands. I've not got any, unless I sort out one of my old top-loaders and record the 405-line converted output from the PC.

I think it should prove possible to capture and record natively in 405-line (or rather a digital equivalent thereof, I seem to remember working it out as 512 x 384 but this might change) without scaling. The digital recordings could then be played back on a PC connected to a 405-line set with no loss due to conversion. You wouldn't be able to burn these to DVD as a DVD, if you see what I mean; but they could be stored on hard drive, DVD or CD as MPEG files; which might be good for swapping 405-line recordings amongst ourselves. It's easier to burn a files onto a few DVDs than copy a tape and there's no loss. I think it'd be good to be able to exchange digital 405-line recordings which were 405-line originally and have stayed that way through the capture and encoding processes.

If required the recordings could be converted to 625-line and put on DVD so they'd play back in any regular DVD player as well.

Regards, Kat

[oldeurope]

Originally Posted by Kat Manton

Hi Steve,

I thought there'd be some interest in this, as I know there are a fair few 405-line recordings in private hands. I've not got any, unless I sort out one of my old top-loaders and record the 405-line converted output from the PC.

I think it should prove possible to capture and record natively in 405-line (or rather a digital equivalent thereof, I seem to remember working it out as 512 x 384 but this might change) without scaling. The digital recordings could then be played back on a PC connected to a 405-line set with no loss due to conversion. You wouldn't be able to burn these to DVD as a DVD, if you see what I mean; but they could be stored on hard drive, DVD or CD as MPEG files; which might be good for swapping 405-line recordings amongst ourselves. It's easier to burn a files onto a few DVDs than copy a tape and there's no loss. I think it'd be good to be able to exchange digital 405-line recordings which were 405-line originally and have stayed that way through the capture and encoding processes. ...

Regards, Kat

This sounds good! I have a radeon 9000 graphic card with RCA vision in and out. Is it possible to use this one?

Kind regards,
Darius

[Kat Manton]

Hi,

Originally Posted by oldeurope

This sounds good! I have a radeon 9000 graphic card with RCA vision in and out. Is it possible to use this one?

I'd have to find out how well (if at all) this card is supported by Linux, then how well it will do non-standard timings. Then get one myself.

At present, only nVidia cards GeForce4 and later (tested with GeForce4 and FX5200) are known to work for generating obsolete standards - not an issue if you're generating 625-line of course; any card with TV out will work provided the card is supported by Linux - and some aren't.

The card I'm going to reprogram for capture is based on the Conexant Bt878A chip as they're common, I've got three of them, I've already deduced that it'll work, I know how to do it and the documentation is available freely for the device. So that's the only one that'll work for capturing 405-line unless I repeat all the work for another device, provided documentation for it is available freely and I can get one for testing myself.

Regards, Kat

[FrankT]

Originally Posted by Kat Manton

If required the recordings could be converted to 625-line and put on DVD so they'd play back in any regular DVD player as well.

Regards, Kat

That is exactly what I want to do. I have at this moment 4 hours of original 405 line recordings on 4 tapes recorded on a CV2000B. More recordings will be sent to me, including the marriage of the owner recorded with a 405 line camera in 1969. At this moment, I have recovered the tapes by pointing a camera to a monitor. Gives a viewable result but I guess doing it electronically would be better. Here a video still from the result.

Frank

[presheaven]

Originally Posted by Kat Manton

I think it should prove possible to capture and record natively in 405-line (or rather a digital equivalent thereof, I seem to remember working it out as 512 x 384 but this might change) without scaling.

Hi

Forgive me for coming onto your forum and bumping old threads.

Firstly, I'd like to ask how is this project coming along?

Seondly, the 512x384 resolution of the 405 line image is what it would be in square pixels, it may be that 405 line tv is non-square pixels, I don't know. You'd have to work out how non-square they are and get your width by working it out in non-square pixels.

For capturing 625 line stuff, I use a DV cam connected to the computer. This sends an image that is 720x576, which is non-square digital PAL format. DVDs are also in non-square pixels. A square pixel digital PAL format would be 788x576. It has 20 more pixels width than an analogue image, making analogue 768x576 which squashes to about 702x576 I think in non-square pixels. I don't use capture cards, but it seems some of them cut off the extra pixels at the left and right and / or convert to 768x576, as a lot of captures I see on YouTube etc. do not have the thin black bars at the sides that I would expect.

You'd have to work out if you needed any extra pixels at the left and right for 405 line capture. I don't think you would, as long as you scaled and framed the image properly in the 720x576 area if converting to 625 lines.

You probably already know all this though

[ZudoBug]

Originally Posted by presheaven

Hi

Forgive me for coming onto your forum and bumping old threads.

Firstly, I'd like to ask how is this project coming along?

I'd imagine that DScaler could be used for this, as it's open source and may allow you to enter detailed custom video input specs before compiling.
I haven't checked this as yet, though.

[Kat Manton]

Hi,

Originally Posted by presheaven

Firstly, I'd like to ask how is this project coming along?

So far, so good. I'm pretty sure I can modify the capture card driver to capture analogue 405-line video.

What's held the project up is I've not had a source of 405-line analogue video other than the output of the MythTV system. This is more an approximation, close enough for 405-line sets to sync to and fine for watching DVDs and Freeview. But I'd prefer to have a source of 405-line video that's a bit closer to specification.

I'm working on that, I have a 405/525/625-line TV camera and its CCU and will soon have a 405/525/625-line sync-pulse generator to drive it with. I know that the SPG works but it may need a little TLC. The camera and CCU are complete unknowns as I've been unable to do anything without an SPG. I do, at least, have two NOS vidicon tubes for it, one studio grade and one telecine grade. Apart from the tubes there's nothing else I'd struggle to replace as both camera and CCU use discrete transistor circuitry.

Once I've got it all working I'll finally have a good source of 405-line video and can start work on capturing it.

Originally Posted by presheaven

Seondly, the 512x384 resolution of the 405 line image is what it would be in square pixels, it may be that 405 line tv is non-square pixels, I don't know. You'd have to work out how non-square they are and get your width by working it out in non-square pixels.

As it's an analogue TV system it doesn't have pixels until it's been digitised.

It may work out that the pixels aren't square as captured, that'll depend on how the timings work out when I reprogram the capture card.

I don't see it as particularly important as, once captured, it's easy enough to scale if needed.

None of the obsolete standards I'm producing from the MythTV system come out with square pixels (but this doesn't matter.) I'm half expecting the same thing to be true of the capture cards, neither they nor the graphics cards were ever designed with 405-line in mind.

Thanks for asking though, it's given me the chance to say "I'm still working on it"

Cheers, Kat

[Steve_P]

A while ago I was talking to Beery about buying an EX-BBC 625 to 405 Standards Converter off him. Auroras etc are all very well, but this would generate 405 exactly to BBC Standards and will be fed off anything 625.

It's got a slight fault, but it does work fairly well and the timings etc are all spot on. It comes with manuals, spares etc. and I still want it! (It's the Digital one - the only Analogue one I know is at Gerrys and does not work.)

If I buy it and lend it to you, then the 405 you'll be working from will be 'Real 405' just as was transmitted.

Fix the fault if you want too.

Cheers,

Steve P.

P.S. Won't you need to generate lines rather than take them away to convert the other way?

[ppppenguin]

Originally Posted by Steve_P

Auroras etc are all very well, but this would generate 405 exactly to BBC Standards and will be fed off anything 625.

The output fromt he Aurora has timings etc that are effectively identical to the BBC CO6/509. In some respects, such as comb filtering at the input, the Aurora is superior. The Aurora has only 3 line vertical interpolation as against 4 for the BBC converter. The BBC's own research on this subject suggests that the difference is very marginal.

The CO6/501 analogue converter has only 2 line interpolation which was the best that could be done at the time.

By all means run the BBC converters out of interest but don't assume that they will be better than the Aurora because they aren't.

Converting 405 to 625 means using interpolation to make extra lines. As a result, the vertical resolution can be no better than the 405 original.

[Kat Manton]

Originally Posted by Steve_P

Won't you need to generate lines rather than take them away to convert the other way?

I don't have to do anything, it's all taken care of by Xv (the X video extension) and the GPU on the graphics card. Video of any resolution can be scaled to the resolution of the display.

Once the work's done on programming the capture card for 405-line timings, that's it. Converting it then involves nothing more than playing it full-screen, conversion being handled automatically. It's pretty much the same as watching a DVD on a computer monitor.

I just thought I'd mention this before the discussion wanders off into areas which already work. This is why I like this system, most of the work's already been done

Cheers, Kat

[Kat Manton]

Hi,

Originally Posted by ZudoBug

I'd imagine that DScaler could be used for this[...]

DScaler could probably be made to work but, after a quick look at the website I have some reservations.

1. It's Windows software and, open-source or not, I don't "do" Windows.
2. It appears to be a typical single-purpose monolithic Windows application.
3. It appears to be primarily for capture, deinterlacing and scaling for output to progressive-scan monitors.

The advantage of modifying a Linux capture card driver to support 405-line is that existing applications written to work with captured video should work without modification.

To my mind this makes the effort worthwhile. The OS itself will then support 405-line video capture; what you do with it and what applications you do it with are left to you

Cheers, Kat

[FrankT]

Hi Everybody,
Great to see that here is still interest in this thread. For the fans, I have posted some of the material from the 405 line tapes on Youtube (amongst other stuff). Not an electronic conversion, but optical. Some of the material is not present in any TV archive and is the only surviving recording.

http://www.youtube.com/user/videorestore2

What if I tried to make a VHS (or U-matic, Betamax, or any other analogue system) copy of the 405 line material? Would that help as a 405 line source? I think that the natural instability of the CV2000B signal could cause problems in the process also. I have such an experience with 625 line Akai VT100 recordings. When played on a monitor they play reasonably well. When feed in to a DVD recorder there are black lines in the picture. My TBC also has problems with the signal.

Cheers.
Frank

[DoctorWho]

I was just wondering, out of interest, if Darryl has considered a 405 to 625 Aurora? Would it even be possible? I'm guessing that, since he has developed the 625 - 819 Aurora then 405 to 625 should be possible?

I'd be interested to hear your thoughts on this Darryl if appropriate.

[ppppenguin]

405 to 625 wouldn't be possible with the existing hardware. The video input on the Aurora is a standard decoder chip which can only take ordinary 625 and 525 signals. The output arrangments are Darryl's own design and can be programmed to do more or less anything.

[tubesrule]

Jeff is correct. It would require a completely different video decoder section, so would not be possible with the current design.

Darryl