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Clean resolution & refresh rate on CRT TV using HDMI out?


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One detail I forgot to mention:

 

You may want to confirm that the unit I linked to can handle 2560x240p i.e "Super Resolutions". I'd guess at a firm yes, but you could msg the seller to make sure. Same goes for any competing unit you find.

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That's fine. The VGA-to-5-BNC cable (in this case running backwards) will work to carry RGBS over 4 lines. And the converter I linked says it takes C-Sync.

 

The recommendation was more about the fact that no modern or semi-modern GPU can output c-sync over VGA, so the 5 cables would be needed to get a complete RGBHV signal out of a PC, if you wanted to do that down the track. You'd need to for a PVM, or to use an Extron or other scaler or sync-combiner.

 

I see some chips that split vertical sync from composite sync, can composite sync be fed into the Horizontal Sync? So split out the V-Sync and the pass it in as V-Sync (of course) and the C-Sync as H-Sync?

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I see some chips that split vertical sync from composite sync, can composite sync be fed into the Horizontal Sync? So split out the V-Sync and the pass it in as V-Sync (of course) and the C-Sync as H-Sync?

 

Depends on the scenario. If you're referring to the VGA-to-YPbPr unit I linked to above, there's no need. Composite sync is an amalgam of H- and V-sync, and the unit is question takes Composite-sync on the H-sync line. It's in the description.

 

If something takes both Composite- or separate H- and V-sync, 99% of the time C-sync goes into the same place as the H-sync would. Sometimes you have to tell the device or chassis or whatever it is about the sync, but a lot are automatic. I believe there are even devices that can work out C-sync when only given H-sync, but you can't rely on that.

 

If you have a device that needs separate sync, something like the LM1881 will normally work. You can feed that IC either Composite Video or Composite Sync. You then feed the outputted C-sync into your device on the H-sync line, and V-sync is V-sync. Different IC's might be affected by differing sync polarities, though. The norm is to have black level at ground or zero volts. All the video information is above zero volts, and the sync information is below, or negative. Some devices use positive polarity on one or both sync channels though, and you can set your PC to deliver that if needed. Other devices and IC's you'd have to deal with as required.

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If you have a device that needs separate sync, something like the LM1881 will normally work. You can feed that IC either Composite Video or Composite Sync. You then feed the outputted C-sync into your device on the H-sync line, and V-sync is V-sync.

 

Exactly the scenario I was thinking of.

 

 

Sent from my iPhone using Aussie Arcade

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  • 2 weeks later...

@buttersoft Thanks again :) Dammit I was waiting for an email notification, and I must have missed it, it's been a week since your reply. Came back to check manually (I have this actual thread page bookmarked, hahah.)

 

I should have given you a better link; upon closer look it doesn't have as many as I thought. Here's the kind of thing I was looking at http://www.ebay.com/itm/Monoprice-VGA-to-Component-YpbPr-Converter-MLKV2300-/172666650040

 

Wow that one you linked to has been 3D printed and assembled by hand. But at least we can be sure it's been created with care. I was concerned about the digital nature of DVI being interpreted by an analogue VGA device, but I've been reading that DVI-I automatically switches to analogue if you use a VGA adaptor. If I can plug that video card into an old VGA monitor with a DVI to VGA adaptor and it works (which it does) do you think that's definitive proof that it will work with such a device?

 

I found the Jaycar link in that thread. https://www.jaycar.com.au/rgb-to-component-video-converter-kit-kit-back-catalogue/p/KC5398 - so what does it input? They tease with that screen shot. Only showing the component outputs and no input sockets.

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That one you've linked to is not ideal. The fact you can pick the output resolution means it's processing the signal, it's not a passive, real-time conversion like the one i linked to. This thread started with you asking for advice on how to get the best result, the best picture you could for emulation (on an CD CRT TV that has component inputs) and the device you've linked to is not the answer as it is scaling or resampling the picture. In addition to which, it will add lag.

 

There's a company called Shinybow in the US that makes high end but affordable video gear that you could use. But it'll probably be more expensive than the one i linked to. I don't know about others, but there must be more out there.

 

The jaycar unit is incomplete. From the look of things it takes RGsB and outputs YPbPr. The VGA signal from a PC is RGBHV; in other words the sync is split in Hor and Ver, and not part of the green line. It also has RCA inputs to do this. I know of very few devices that output RGsB save the PS2, which would also output component. I was hoping someone would turn up a conversion circuit to turn RGBHV into RGsB, or Sync-on-Green, as it's knowb, but it may be a case of hunting one down. And then you'd have to build it.

 

To recap, you want to start with a PC on Win 7 or Win 10, and a Radeon 5000 series card or newer, up to an R9 card, that has a DVI-I port (using the adapter you mentioned). Make sure the Radeon card has a DVI-I port, as a DVI-D port will look the same a lot of times. Then you need the RGB-to-component/YPbPr converter we're talking about now. Then you go back in the thread and find the guides i linked to, to get 240p resolutions out of your PC.

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Just quickly, the Jaycar items are kits associated with silicon chip magazine. I put up a post seeing if we could get copies off subscribers. I will try to get around to working out which issues are to do with the RGB/Component (and vice versa) devices and put the list in that post.

 

 

Sent from my iPhone using Aussie Arcade

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Thanks @buttersoft. Yep I totally understand the difference between a device that is doing a neat real-time conversion vs something that is doing some processing that will add artifacting and lag.

 

So these "transcoders" seem pretty obscure! Going by the fact that the only one you've linked me to is a hand-made thingy with a 3D printed case. That's a shame, it seems as if we are running out of options to output from more modern video cards to CRTs.

 

I was messaging the guy selling the transcoder you linked to, and he said the device wouldn't work using the output from a PC, but I assume that's what the crt emu driver 2.0 is for, and I've just informed him of this to see what he says.

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Hi

 

I am the creator of the VGA to Component transcoder you guys are discussing and I wanted to clear some things up.

 

This device WILL work with PCs or any other analog device that you connect to it (consoles, arcade boards, etc). The dependency is the display device you connect the component output to.

 

For example, if you use a 15KHz standard definition VGA signal for the input, the component output will work on any SD CRT and likely any HDTV CRT, but probably won't work on modern LCDs.

If you use 31KHz+ Arcade/PC resolutions, the component output will NOT WORK on SD CRTs, but will work on HDTV CRTs and LCDs.

 

There is a caveat with most modern LCDs when using PC resolutions however. The vast majority use signal processing to determine if it will display based on the horizontal scan rate. The usually filter out any resolutions that are not 480p, 720p, and 1080i. So PC resolutions like 800x600 and 1024x768 usually won't display on LCD TVs. The trancoder works fine at these resolutions, but LCD signal processing will refuse to display them.

 

Usually CRT HDTVs don't have this type of processing and will directly display these resolutions just fine.

 

I'd be happy to answer any more questions or clear up any confusion.

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Hahah cool, you found my thread @Fusion916 (and I only mentioned "Aussie Arcade forums" by name!) Thanks for the info.

 

I was thinking of testing out crt emudriver 2.0 by installing it and then sticking with the current S-Video setup, see if it outputs the low resolutions to the TV successfully via S-Video. Just to see if I can use it correctly and get a low res image showing up on the TV. After that, I would test the new video card by using a DVI to VGA adaptor on a VGA monitor to make sure it outputs analogue correctly (which it probably will). I guess if I do those two things, the transcoder should work for me with the new video card. Just want to check before I throw down $160 AU :) (that figure includes the shipping)

 

@buttersoft I saw this cable and thought it might work with the Jaycar unit, but I suppose not if there's a difference between the RGB format coming from the PC, and the RGB format that the device takes, like you said. http://www.ebay.com/itm/10Ft-Premium-VGA-SVGA-to-3RCA-RGB-Component-Video-Cable-For-TV-Monitor-Projector-/142049203509?hash=item2112cad535:g:SHcAAOSwRQlXgAnN

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@Fusion916 thanks man. I was recommending the unit for a 1:1 resolution translation, from a PC outputting 15kHz to an SD CRT that takes YPbPr :) What's the bandwidth limit on your unit, out of interest? I presume it would be fine with super resolutions (2560x240p, etc) as recommended for GroovyMAME?

 

Also, we had a thread on here a while back looking for the schematics to do what your unit does - http://www.aussiearcade.com/showthread.php/86709-Silicon-Chip-Subscribers but that unit only appears to take Sync-on-Green. IF you'd be willing to share the schema you use that would be awesome. Given you sell the finished items it may not be in your interest to, so it's totally cool if you don't want to.

 

@Domarius nope, that cable is no good. To use it you'd need a device or PC outputting RGsB, or YPbPr over VGA directly. Some esoteric older PC's might have been able to, but not anymore AFAIK. And even then you'd need to pumping out 15kHz...

Edited by buttersoft
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@buttersoft Thanks. I go back to your original big post from time to time to think about which path I want to go. I have to make a choice of 3;

 

1. Most accurate visuals: VGA to Component transcoder ($160 AU) What I will get is scanlines (which is great, don't get me wrong), but I will lose almost ALL modern "retro" style games available on Steam, since I had a look at some and a lot of them don't want to drop down to 640x480, somewhat ironically, given their actual visual resolution is somewhere around 320x200. (Eg. Shantae and the Pirate's Curse) and they look good on a CRT.

 

2. Biggest library: HDMI to Component converter (also nearly $160 AU) This will let me use the better video card and enable me to play pretty much every single game worth playing on this arcade cabinet from the Steam library (4 player local games, "retro themed" games, etc.) I'd lean towards this at the moment EXCEPT for the fear of introducing lag, which will be unacceptable for all the older games, which often need twitch reflexes. (Lack of scanlines I might live with for the sake of a bigger game library, but not lag.) However, I'm not sure a lag will be introduced. It's just a concern you've raised which I'm taking very seriously.

 

3. Best of both worlds: My current S-Video setup (free). The retro games appear to me to be perfect (running at 1024x768 removes the "pixel swimming" effect when scrolling), except for the absence of scanlines, which is a shame, since they do look much better with them. (Tried to apply a filter, it did not go well, whole screen went dim as I assume the fake scanlines didn't line up with the real ones, possibly a case of finding the right filter per emulator?) And regarding the steam games, most of them seem to run. It's just a small / moderate number of Steam games refuse to run on the old video card with the S-Video output, due to DirectX incompatibility or just bad performance.

 

 

I get it - I'm fighting an uphill battle trying to pull together old and new gaming technologies that have 30 years between them, but goddammit, I'm going to see how close I can get, and then go from there. Currently thinking of keeping my current setup (option 3) and having the livingroom PC kitted out with the steam games that refuse to run on the old video card. Not ideal, I'd like the 4 player arcade cabinet that I've put so much work into being easily accessible to be able to run those games too.

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Yer that, pretty much it, save that crt_emudriver will work with a lot of R9 cards, and Calamity will no doubt release an update for even newer cards as soon as you buy one. So you can get a fair amount of juice from those.

 

You should maybe try setting up a test system that *only* has 640x480 on it (you can use VMMaker without needing to go through crt_emudriver) and seeing what will run when there's no higher resolution to pick. You might be surprised. Stuff like Grid2 will run in 640x480, and the game looks ok, though the smaller option menus and icons are illegible.

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