405 from digital - for dummies - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Panrock · 21st Jun 2023, 6:43 pm

But not PAL? Always NTSC... right?

The point I'm making is that if it's a signal with PAL colour encoding, its field rate will always be 50Hz. But when the field rate is 60Hz, then it will always be an NTSC signal.

FRANK.C · 21st Jun 2023, 7:13 pm

Hi Steve
Yes you are right.

I have one of those HDMI to composite boxes linked to in post #6.
When set to PAL the output is 625 lines 50Hz
When set to NTSC the output is 525 lines 60Hz.

I used one when getting the Hedghog PSC to be able convert from PAL or NTSC.
It was a very convenient way of switching between the two standards.

Frank

thermionic · 21st Jun 2023, 7:34 pm

Quote:

Originally Posted by Panrock

Hi SimonT,

It's the "small HDMI to composite video box" you mention that I'd be interested in learning more about.

Steve

Hi Steve.

This one looks almost identical to mine https://cpc.farnell.com/av-link/128-...yABEgKDPfD_BwE

I’ve had mine for a while now and it works well with the FireStick.

Cheers. SimonT.

Panrock · 21st Jun 2023, 7:54 pm

That looks very interesting!

Now, the ultimate product would be one of these that also included aspect ratio 'chopping'. Does such a thing exist?

paulsherwin · 21st Jun 2023, 7:59 pm

No. That's not how HDMI/CVBS interfaces work. The device is controlled by the computer which determines what goes down the pipe.

Panrock · 21st Jun 2023, 8:05 pm

Good to have the benefit of your knowledge Paul. Thanks.

FRANK.C · 21st Jun 2023, 8:18 pm

Quote:

Originally Posted by Panrock

That looks very interesting!

Now, the ultimate product would be one of these that also included aspect ratio 'chopping'. Does such a thing exist?

Hi Steve
Any of the Hedghogs will do the aspect ratio chopping from 16:9 to 4:3 or 5:4

Frank

Panrock · 21st Jun 2023, 8:30 pm

I can feel a Hedghog 'coming on'. If there are any good/used ones available out there, a PM please.

paulsherwin · 21st Jun 2023, 8:34 pm

Yes, you need a smarter device to do this. However, if you tell the computer to use a 1024*768 resolution for the device, it will display fullscreen material as 4:3. (It will display 16:9 fullscreen material as matchstick men though).

This is all an imprecise science though, and given that these gizmos only cost four quid including postage you might as well order one and have a play around.

cmjones01 · 21st Jun 2023, 8:51 pm

I've got one of these little composite converter boxes connected to a spare HDMI port on my PC and it does output honest 50Hz PAL. I use it to drive a Philips CRT TV with very good picture quality - the PAL encoding seems good.

The only caveat is that I haven't yet found a 4:3 PC graphics format it accepts at 50Hz. I use 1024x768, which gets a correctly shaped 4:3 picture, but the PC's refresh rate is then 75Hz. Although it all works, the resulting frame rate conversions are noticeable on some types of moving material. The box does support native 50Hz input but only at 720p/1080i/1080p as far as I can see, all of which are 16:9 formats and wrong for my TV.

Chris

murphyv310 · 21st Jun 2023, 9:44 pm

Hi.
Chris that is indeed the issue as it's difficult to get a smooth picture when converting frame rates.
I'm not sure what the "firestick" type dongles give out but the Roku Box I have worked well with the HDMI converter to a Hedghog and set to 4:3.
Incidentally if anyone still uses a VCR for 405 I can record from the PC and send a tape to get an idea how well this works, VHS only though.

cmjones01 · 22nd Jun 2023, 10:55 am

Different sources will surely have different resolutions possible at 50Hz, and something like a Roku box can probably do anamorphic 4:3 in a 1080i frame, which is what the HDMI converter box would really like.

I've taken some pictures to show how it looks. It's very hard to get representative photos (the CRT shadow mask gives my phone camera a very hard time) but the picture is as good as I could reasonably expect a 14" PAL colour CRT to be.

Chris

paulsherwin · 22nd Jun 2023, 10:59 am

That is very much what I would expect.

Panrock · 23rd Jun 2023, 4:39 pm

The two little 'black boxes' on this thread from Ebay and Farnell are differently branded but they otherwise look identical - and are ideal. I intend to order one.

One query. I shall want to keep my existing PC monitor display running alongside the new box. But there is only on HDMI connector on my PC and one on the monitor.

So again, an elementary question: How can two HDMI ports be derived from just one?

Thanks.

paulsherwin · 23rd Jun 2023, 4:44 pm

They can't. You will need an additional graphics card.

What is your PC?

Panrock · 23rd Jun 2023, 5:16 pm

See the attached, which should tell you all you need to know. I have a higher definition snap to refer to if necessary.

paulsherwin · 23rd Jun 2023, 5:37 pm

OK, so one of these: https://support.hp.com/gb-en/document/c05088556

That does appear to have very limited expansion capabilities - it's pretty much a laptop mobo in a desktop case. Other forum members are more familiar with HP kit than I am though, and may be able to give you better advice.

Can you connect your desktop monitor using the analogue VGA interface?

Panrock · 23rd Jun 2023, 6:10 pm

Quote:

Originally Posted by paulsherwin

Can you connect your desktop monitor using the analogue VGA interface?

Would this be effected by using the 15-way D-type connectors? I don't have a lead, but if I did, what would happen if I plugged it in alongside the HDMI? Would a 'choice' menu be presented?

paulsherwin · 23rd Jun 2023, 6:23 pm

It depends on the implementation, but both HDMI and VGA interfaces would probably carry the same information. It would be effectively like splitting the HDMI interface, though there will be some quality degradation with the VGA interface.

McMurdo · 23rd Jun 2023, 7:01 pm

Here's my solution for 'show me youtube on a 405 line telly'.

First - no computer needed. Source of stuff off the internet (any streaming video including youtube/vimeo/dailymotion/BBC iplayer/all-4/5OD etc) is a £30 'roku' box from Argos. It is the size of a cigarette lighter and picks up the internet off your wifi router. It has a remote control and menus so you can browse internet video at will. It needs 5V power from a usb adapter, or old usb phone charger, what-have-you. Output is HDMI on a supplied cable.

Next, the roku box output (hdmi) is converted to composite video (selectable NTSC/PAL) via the adapter in the pics below. It has HDMI passthrough for a monitor TV and also outputs on SCART in RGB and Composite. It too needs a supply via a 5V wall wart, again any sort will do. Mine came from amazon. (the converter)

The scaling for the output is done via a little push button that cycles through the various options, zooming into widescreen pictures to crop the letterboxing to give a full picture if required at 4:3 (or 5:4

). A seperate audio output (stereo mini jack) is provided if you want to output to a hifi without having a tv turned on, for example streaming music channels. PS..the converter compsite will have to then be plugged into your aurora for 405 line).

(link to roku box in richer sounds)

https://www.richersounds.com/roku-express.html

21st Jun 2023, 6:43 pm	#21
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies But not PAL? Always NTSC... right? The point I'm making is that if it's a signal with PAL colour encoding, its field rate will always be 50Hz. But when the field rate is 60Hz, then it will always be an NTSC signal. Last edited by Panrock; 21st Jun 2023 at 6:53 pm. Reason: Clarification

21st Jun 2023, 7:13 pm	#22
FRANK.C Heptode Join Date: Feb 2006 Location: Roscommon, Ireland Posts: 722	Re: 405 from digital - for dummies Hi Steve Yes you are right. I have one of those HDMI to composite boxes linked to in post #6. When set to PAL the output is 625 lines 50Hz When set to NTSC the output is 525 lines 60Hz. I used one when getting the Hedghog PSC to be able convert from PAL or NTSC. It was a very convenient way of switching between the two standards. Frank __________________ www.electronics.frankcuffe.ovh

21st Jun 2023, 7:54 pm	#24
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies That looks very interesting! Now, the ultimate product would be one of these that also included aspect ratio 'chopping'. Does such a thing exist?

21st Jun 2023, 7:59 pm	#25
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies No. That's not how HDMI/CVBS interfaces work. The device is controlled by the computer which determines what goes down the pipe.

21st Jun 2023, 8:05 pm	#26
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Good to have the benefit of your knowledge Paul. Thanks.

21st Jun 2023, 8:30 pm	#28
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies I can feel a Hedghog 'coming on'. If there are any good/used ones available out there, a PM please.

21st Jun 2023, 8:34 pm	#29
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies Yes, you need a smarter device to do this. However, if you tell the computer to use a 1024*768 resolution for the device, it will display fullscreen material as 4:3. (It will display 16:9 fullscreen material as matchstick men though). This is all an imprecise science though, and given that these gizmos only cost four quid including postage you might as well order one and have a play around.

21st Jun 2023, 8:51 pm	#30
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,608	Re: 405 from digital - for dummies I've got one of these little composite converter boxes connected to a spare HDMI port on my PC and it does output honest 50Hz PAL. I use it to drive a Philips CRT TV with very good picture quality - the PAL encoding seems good. The only caveat is that I haven't yet found a 4:3 PC graphics format it accepts at 50Hz. I use 1024x768, which gets a correctly shaped 4:3 picture, but the PC's refresh rate is then 75Hz. Although it all works, the resulting frame rate conversions are noticeable on some types of moving material. The box does support native 50Hz input but only at 720p/1080i/1080p as far as I can see, all of which are 16:9 formats and wrong for my TV. Chris __________________ What's going on in the workshop? http://martin-jones.com/

21st Jun 2023, 9:44 pm	#31
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,388	Re: 405 from digital - for dummies Hi. Chris that is indeed the issue as it's difficult to get a smooth picture when converting frame rates. I'm not sure what the "firestick" type dongles give out but the Roku Box I have worked well with the HDMI converter to a Hedghog and set to 4:3. Incidentally if anyone still uses a VCR for 405 I can record from the PC and send a tape to get an idea how well this works, VHS only though. __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

22nd Jun 2023, 10:55 am	#32
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,608	Re: 405 from digital - for dummies Different sources will surely have different resolutions possible at 50Hz, and something like a Roku box can probably do anamorphic 4:3 in a 1080i frame, which is what the HDMI converter box would really like. I've taken some pictures to show how it looks. It's very hard to get representative photos (the CRT shadow mask gives my phone camera a very hard time) but the picture is as good as I could reasonably expect a 14" PAL colour CRT to be. Chris Attached Thumbnails __________________ What's going on in the workshop? http://martin-jones.com/

22nd Jun 2023, 10:59 am	#33
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies That is very much what I would expect.

23rd Jun 2023, 4:39 pm	#34
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies The two little 'black boxes' on this thread from Ebay and Farnell are differently branded but they otherwise look identical - and are ideal. I intend to order one. One query. I shall want to keep my existing PC monitor display running alongside the new box. But there is only on HDMI connector on my PC and one on the monitor. So again, an elementary question: How can two HDMI ports be derived from just one? Thanks.

23rd Jun 2023, 4:44 pm	#35
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies They can't. You will need an additional graphics card. What is your PC?

23rd Jun 2023, 5:16 pm	#36
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies See the attached, which should tell you all you need to know. I have a higher definition snap to refer to if necessary. Attached Thumbnails

23rd Jun 2023, 5:37 pm	#37
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies OK, so one of these: https://support.hp.com/gb-en/document/c05088556 That does appear to have very limited expansion capabilities - it's pretty much a laptop mobo in a desktop case. Other forum members are more familiar with HP kit than I am though, and may be able to give you better advice. Can you connect your desktop monitor using the analogue VGA interface?

23rd Jun 2023, 6:23 pm	#39
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,169	Re: 405 from digital - for dummies It depends on the implementation, but both HDMI and VGA interfaces would probably carry the same information. It would be effectively like splitting the HDMI interface, though there will be some quality degradation with the VGA interface.

23rd Jun 2023, 7:01 pm	#40
McMurdo Dekatron Join Date: Jun 2009 Location: Staffordshire Moorlands, UK. Posts: 5,173	Re: 405 from digital - for dummies Here's my solution for 'show me youtube on a 405 line telly'. First - no computer needed. Source of stuff off the internet (any streaming video including youtube/vimeo/dailymotion/BBC iplayer/all-4/5OD etc) is a £30 'roku' box from Argos. It is the size of a cigarette lighter and picks up the internet off your wifi router. It has a remote control and menus so you can browse internet video at will. It needs 5V power from a usb adapter, or old usb phone charger, what-have-you. Output is HDMI on a supplied cable. Next, the roku box output (hdmi) is converted to composite video (selectable NTSC/PAL) via the adapter in the pics below. It has HDMI passthrough for a monitor TV and also outputs on SCART in RGB and Composite. It too needs a supply via a 5V wall wart, again any sort will do. Mine came from amazon. (the converter) The scaling for the output is done via a little push button that cycles through the various options, zooming into widescreen pictures to crop the letterboxing to give a full picture if required at 4:3 (or 5:4 ). A seperate audio output (stereo mini jack) is provided if you want to output to a hifi without having a tv turned on, for example streaming music channels. PS..the converter compsite will have to then be plugged into your aurora for 405 line). (link to roku box in richer sounds) https://www.richersounds.com/roku-express.html Attached Thumbnails __________________ Kevin