HD TV - Conversion to 405 and other standards? - UK Vintage Radio Repair and Restoration Discussion Forum

Steve_P · 18th May 2010, 6:32 am

With the increase, in the UK at any rate, of HD Television, I have wondered how long before 625 Line TV is going to be with us. From this, are we going to need an HDTV converter any time soon to run our old sets?

I know something about this, but nowhere near enough to answer this question, let alone build a converter. Does anybody else have any ideas...?

Cheers,

Steve P.

ppppenguin · 18th May 2010, 7:47 am

At this stage we rely on generally available HD boxes to supply and SD output to feed our Aurorae etc. AFAIK all HD boxes so far have an SD output. When this starts to change we will have a problem but I don't think it's one that needs solving yet.

Kat Manton · 18th May 2010, 8:03 am

Hi,

The Linux/MythTV system converts source material to the resolution of the display device regardless of the resolution (or frame rate, or interlacing) of either.

I have yet to try it, but HD source would be arguably a better starting point for conversion to 819. I'll try it once I've finished fixing the set!

So this is a problem I've already solved four years ago

Cheers, Kat

paulsherwin · 18th May 2010, 11:36 am

All the HD boxes I've seen have a standard SCART connector which provides downconverted analogue SD video. I suppose this may be discontinued at some stage, but it's likely to linger on for many, many years.

There is no immediate prospect of extensive HD on Freeview because of bandwidth limitations. The proposed four HD channels have raised many concerns because of the heavy compression required, leading to accusations that it is simply 'HD lite' or 'SD plus' and not worth bothering with. This subject is OT for the forum though.

Paul

ppppenguin · 18th May 2010, 11:44 am

When the times arrives that it's hard to find anything with conventional SD analogue output - and it doesn't look like anytime soon - let's hope that Darryl is around to make a little box with HDMI (or whatever) input and 405 etc out. It's not conceptually any harder than the existing Aurorae.

tubesrule · 18th May 2010, 1:55 pm

I have been asked about this many times over the years. We have fully converted to digital over here, and just as in the UK, all the OTA, Cable, DVD, etc. boxes have SD analog outputs and that doesn't appear to be changing anytime soon.

The bad news is the AACS is requiring ALL analog outputs be eliminated from BluRay hardware by the end of 2013. (also no analog HD after the end of 2010, just analog SD) They are calling this the "Analog Sunset".

To complicate matters, HDMI uses the HDCP protection scheme. With this scheme, the content provider (the actual disk itself) gets to decide if the device attached is allowed, and will disable the output if not. (The stated intent is to stop piracy but is more to do with Hollywood wanting ultimate control) This means that all devices need to license HDCP or may not work. For Sony, JVC, Panasonic, this is certainly not an issue. For people making one off devices this is a show stopper. Unfortunately this will affect all HDMI input devices that have the ability to copy or record the data. As of now, the only devices that will be HDCP compliant are display devices and broadcast equipment.

So that is the threat right now. Will it turn out that the studios actually enforce this? Who knows. As long as they don't than a low cost HDMI input can be had. Since this is up to the studios there will also be content released without enforcing HDCP, so there should be some content available, just maybe not everything you would want. Also it is unclear if this will extent to OTA HD. As of right now we should always be able to grab clear OTA data.

Darryl

Boom · 18th May 2010, 2:07 pm

If it comes to it I have yet to see any encryption system that can stop an optical transfer.

Dave

tubesrule · 18th May 2010, 2:53 pm

Quote:

Originally Posted by Boom

If it comes to it I have yet to see any encryption system that can stop an optical transfer.

Dave

So true Dave, and the AACS actually admits that high quality optical copies are easy to do today making these encryption schemes less effective, so perhaps they will not push this to it's full extent.

Darryl

julie_m · 18th May 2010, 3:53 pm

If anybody makes a HDTV set with a CRT, then you can get the analogue RGB drives from the tube base (just need a bit of signal conditioning) and work out where the beam is on the screen from the scan coil drives.

dark1stu · 27th May 2010, 9:46 am

I believe Sony make a CRT HD monitor for broadcast use and I think there may be a TV about as I saw something on Sky where they were comparing a CRT HD TV and an LCD offering.

ppppenguin · 27th May 2010, 11:22 am

Using the RGB from a CRT is a horrible way to do it. Yes of course there are professional CRT HD monitors but they are expensive items. Even if domestic CRT HDTVs exist they are rare and will get even rarer. Also who wants a huge lump of modern-ish CRT hardware sitting around as part of 405 converter.

When the time finally comes that analogue interconnect disappears we will be stuck with HDMI. Or whatever may replace HDMI by then. There are solutions to the HDMI encryption problem but I don't think we would be allowed to discuss them here.

Boom · 27th May 2010, 1:34 pm

I saw a HDTV for the first time the other day. It was on display in Tescos showing a testcard. The picture was very clear indeed but what struck me as odd was that both the bottom frequency gratings were unresolved. Is this normal or am I misunderstanding the meaning of HDTV?

Dave

julie_m · 27th May 2010, 1:42 pm

Quote:

Originally Posted by ppppenguin

Using the RGB from a CRT is a horrible way to do it.

But you only have to do it once

dark1stu · 28th May 2010, 9:31 am

Just a thought, has anyone tried using a pc to output to a old TV as they can scale and resize inputs using software and you only need to pick out the luminance signal for a b&w TV.

In theory you could use a DVB card in the pc and output it as composite vid at 400 lines as a lot of the older cards can do this, I only know this due to messing with old game cabinets and running them off a pc. This was done in DOS, but I would not mind guessing someone with a bit if know how could convince Windows to do this.

ppppenguin · 28th May 2010, 11:28 am

Quote:

Originally Posted by dark1stu

Just a thought, has anyone tried using a pc to output to a old TV as they can scale and resize inputs using software and you only need to pick out the luminance signal for a b&w TV.

Yes, it's entirely feasible. See post #3 in this thread. I think Kat's work was the subject of a thread some years ago.

julie_m · 28th May 2010, 11:35 am

Quote:

Originally Posted by dark1stu

Just a thought, has anyone tried using a pc to output to a old TV as they can scale and resize inputs using software and you only need to pick out the luminance signal for a b&w TV.

Our own Kat Manton has been doing just that. Search her threads .....

18th May 2010, 6:32 am	#1
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	HD TV - Conversion to 405 and other standards? With the increase, in the UK at any rate, of HD Television, I have wondered how long before 625 Line TV is going to be with us. From this, are we going to need an HDTV converter any time soon to run our old sets? I know something about this, but nowhere near enough to answer this question, let alone build a converter. Does anybody else have any ideas...? Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

18th May 2010, 7:47 am	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: HD TV - Conversion to 405 and other standards? At this stage we rely on generally available HD boxes to supply and SD output to feed our Aurorae etc. AFAIK all HD boxes so far have an SD output. When this starts to change we will have a problem but I don't think it's one that needs solving yet.

18th May 2010, 11:36 am	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: HD TV - Conversion to 405 and other standards? All the HD boxes I've seen have a standard SCART connector which provides downconverted analogue SD video. I suppose this may be discontinued at some stage, but it's likely to linger on for many, many years. There is no immediate prospect of extensive HD on Freeview because of bandwidth limitations. The proposed four HD channels have raised many concerns because of the heavy compression required, leading to accusations that it is simply 'HD lite' or 'SD plus' and not worth bothering with. This subject is OT for the forum though. Paul

18th May 2010, 11:44 am	#5
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: HD TV - Conversion to 405 and other standards? When the times arrives that it's hard to find anything with conventional SD analogue output - and it doesn't look like anytime soon - let's hope that Darryl is around to make a little box with HDMI (or whatever) input and 405 etc out. It's not conceptually any harder than the existing Aurorae.

18th May 2010, 1:55 pm	#6
tubesrule Hexode Join Date: Jul 2004 Location: Michigan USA Posts: 325	Re: HD TV - Conversion to 405 and other standards? I have been asked about this many times over the years. We have fully converted to digital over here, and just as in the UK, all the OTA, Cable, DVD, etc. boxes have SD analog outputs and that doesn't appear to be changing anytime soon. The bad news is the AACS is requiring ALL analog outputs be eliminated from BluRay hardware by the end of 2013. (also no analog HD after the end of 2010, just analog SD) They are calling this the "Analog Sunset". To complicate matters, HDMI uses the HDCP protection scheme. With this scheme, the content provider (the actual disk itself) gets to decide if the device attached is allowed, and will disable the output if not. (The stated intent is to stop piracy but is more to do with Hollywood wanting ultimate control) This means that all devices need to license HDCP or may not work. For Sony, JVC, Panasonic, this is certainly not an issue. For people making one off devices this is a show stopper. Unfortunately this will affect all HDMI input devices that have the ability to copy or record the data. As of now, the only devices that will be HDCP compliant are display devices and broadcast equipment. So that is the threat right now. Will it turn out that the studios actually enforce this? Who knows. As long as they don't than a low cost HDMI input can be had. Since this is up to the studios there will also be content released without enforcing HDCP, so there should be some content available, just maybe not everything you would want. Also it is unclear if this will extent to OTA HD. As of right now we should always be able to grab clear OTA data. Darryl

18th May 2010, 8:03 am	#3
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Re: HD TV - Conversion to 405 and other standards? Hi, The Linux/MythTV system converts source material to the resolution of the display device regardless of the resolution (or frame rate, or interlacing) of either. I have yet to try it, but HD source would be arguably a better starting point for conversion to 819. I'll try it once I've finished fixing the set! So this is a problem I've already solved four years ago Cheers, Kat

18th May 2010, 2:07 pm	#7
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: HD TV - Conversion to 405 and other standards? If it comes to it I have yet to see any encryption system that can stop an optical transfer. Dave

18th May 2010, 3:53 pm	#9
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: HD TV - Conversion to 405 and other standards? If anybody makes a HDTV set with a CRT, then you can get the analogue RGB drives from the tube base (just need a bit of signal conditioning) and work out where the beam is on the screen from the scan coil drives. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

27th May 2010, 9:46 am	#10
dark1stu Pentode Join Date: May 2010 Location: Wolverhampton, West Midlands, UK. Posts: 154	Re: HD TV - Conversion to 405 and other standards? I believe Sony make a CRT HD monitor for broadcast use and I think there may be a TV about as I saw something on Sky where they were comparing a CRT HD TV and an LCD offering. Last edited by Darren-UK; 27th May 2010 at 11:11 am. Reason: FSK problem fixed.

27th May 2010, 11:22 am	#11
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: HD TV - Conversion to 405 and other standards? Using the RGB from a CRT is a horrible way to do it. Yes of course there are professional CRT HD monitors but they are expensive items. Even if domestic CRT HDTVs exist they are rare and will get even rarer. Also who wants a huge lump of modern-ish CRT hardware sitting around as part of 405 converter. When the time finally comes that analogue interconnect disappears we will be stuck with HDMI. Or whatever may replace HDMI by then. There are solutions to the HDMI encryption problem but I don't think we would be allowed to discuss them here.

27th May 2010, 1:34 pm	#12
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: HD TV - Conversion to 405 and other standards? I saw a HDTV for the first time the other day. It was on display in Tescos showing a testcard. The picture was very clear indeed but what struck me as odd was that both the bottom frequency gratings were unresolved. Is this normal or am I misunderstanding the meaning of HDTV? Dave

28th May 2010, 9:31 am	#14
dark1stu Pentode Join Date: May 2010 Location: Wolverhampton, West Midlands, UK. Posts: 154	Re: HD TV - Conversion to 405 and other standards? Just a thought, has anyone tried using a pc to output to a old TV as they can scale and resize inputs using software and you only need to pick out the luminance signal for a b&w TV. In theory you could use a DVB card in the pc and output it as composite vid at 400 lines as a lot of the older cards can do this, I only know this due to messing with old game cabinets and running them off a pc. This was done in DOS, but I would not mind guessing someone with a bit if know how could convince Windows to do this.