Down conversion to 240p using DVDO machines

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Fudoh
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Down conversion to 240p using DVDO machines

Post by Fudoh »

This is actually something I never even thought of.

Obviously (duh!) some DVDO machines with custom timing support are so flexible, that they even support 15khz 240p output.

This is a VP50Pro. It should also work on VP50 and VP30 units. Edge & Duo with a HDFury are a possiblity.
Input was s-video, hence the visible color bleed.


Image

Image

Image

Image

Image


Timings used for this test:

Code: Select all

     H – shift 55
     H – size  640
     H – front 21
     H – sync  62
     H – back  55 
     V – shift 20
     V – size  240 
     V – front 19
     V – sync  6
     V – back  20
All credits to Blair - thank you!

PS: and thinking of it, even 384p, 24khz output for dual-sync chassis arcade CRTs should be possible!
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Re: Down conversion to 240p using DVDO machines

Post by Xyga »

Zomg :shock: why we never tried this before is a mystery, probably just because the DVDO's have always been categorized as 'upscalers' in our minds period.

Will try this as soon as I get home (in two weeks urgh).

I've still got a VP30 besides the 50pro so it will be easy to see if they're both as flexible for the job.
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Re: Down conversion to 240p using DVDO machines

Post by Lord of Pirates »

The scalers that keep giving :).
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Re: Down conversion to 240p using DVDO machines

Post by emphatic »

Nice find!
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Josh128
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Re: Down conversion to 240p using DVDO machines

Post by Josh128 »

Cool! So in this way it can essentially replace the Emotias for downscaling MAME content to 240p...very nice!
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Re: Down conversion to 240p using DVDO machines

Post by BazookaBen »

Cool stuff Fudoh. It definitely looks like native 240p. What's your guess for the amount of input lag for the 480i>240p conversion?
Fudoh wrote:PS: and thinking of it, even 384p, 24khz output for dual-sync chassis arcade CRTs should be possible!
And maybe the reverse? Say I could hook up a Gradius IV PCB to a PC CRT by line-doubling to 1024x768?
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

What's your guess for the amount of input lag for the 480i>240p conversion?
depends on the deinterlacing mode you choose. Starting from 7ms.
And maybe the reverse? Say I could hook up a Gradius IV PCB to a PC CRT by line-doubling to 1024x768?
won't work. 24khz isn't accepted on the inputs.
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Re: Down conversion to 240p using DVDO machines

Post by Xyga »

Need to double-check but in my stuff I have a BNC RGBHV to scart RGBs cable (HV both wired on pin 19 or 20 I think, don't remember where I got it) wonder if it will do ? (for my crt TV's).
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Re: Down conversion to 240p using DVDO machines

Post by donluca »

Wondering if this will work with my Cinemateq PoP II as well...
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Re: Down conversion to 240p using DVDO machines

Post by RocketBelt »

Will test this on VP50 asap and report back. Can't believe no one ever thought of this before.
Nice find. Can the 50hz timings be found as well?
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Re: Down conversion to 240p using DVDO machines

Post by SGGG2 »

Yet another piece of gear to add to my collection. :)

Someone please test an Edge/Fury combo.
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

Need to double-check but in my stuff I have a BNC RGBHV to scart RGBs cable (HV both wired on pin 19 or 20 I think, don't remember where I got it) wonder if it will do ? (for my crt TV's).
You can simply set the BNC outs to component. Should be easier for testing.

And for RGB you should be able to choose RGBs, so you could just leave the "V" BNC connector unplugged.
Last edited by Fudoh on Fri May 08, 2015 7:56 pm, edited 1 time in total.
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Re: Down conversion to 240p using DVDO machines

Post by BazookaBen »

SGGG2 wrote:Someone please test an Edge/Fury combo.
Not sure if the HD Fury can go below 30hz. So yeah, we need somebody to test.
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Re: Down conversion to 240p using DVDO machines

Post by rugdoctor »

Awesome, more incentive for me to get my edge up and running again...
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

Can the 50hz timings be found as well?
just use the 576p timing and start from there. Reduce the vertical active pixels to 288 and see what happens. You might need to adjust sync and front porch, but it should be close already.
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

DC scan converted to 240p using an iscan HD+

Image

Some more infos - everything work in progress:

- the VP50Pro might have a DAC limitation and not be able to reach down to true 15khz. The internal refresh rate might by rising when the vertical resolution is lowered. An Extron RGB interfaces gives different readings than what the internal settings of the processor show.

- 384p60 (24khz) for cabs with Dual-Sync chassis should be working.

- The iScan HD+ is perfectly able to go down to 240p60 (which might hint at the VP30 working as well).


Timing calculators:

- http://xtiming.sourceforge.net/cgi-bin/xtiming.pl
- http://www.epanorama.net/faq/vga2rgb/calc.html
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Re: Down conversion to 240p using DVDO machines

Post by BuckoA51 »

Damnit Fudoh why didn't you talk me out of sending that 50 pro back? :)

Confused though, you say "Edge is a possibility with HD Fury" but I don't think the Edge supports custom resolutions like the 50pro does it?
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

Confused though, you say "Edge is a possibility with HD Fury" but I don't think the Edge supports custom resolutions like the 50pro does it?
yeah, you're probably right. It's been too long since I had an Edge on hand.
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Re: Down conversion to 240p using DVDO machines

Post by Xyga »

I can also try the Edge (Gr) later (if I can power it on that is, because the PSU's almost fried)

Crap I wanna go home now.
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Re: Down conversion to 240p using DVDO machines

Post by BuckoA51 »

I can also try the Edge (Gr) later (if I can power it on that is, because the PSU's almost fried)
You can't do custom resolutions on the Edge or Edge Green.
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Re: Down conversion to 240p using DVDO machines

Post by Xyga »

Oh yeah forgot about that lol useless edge haha
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Re: Down conversion to 240p using DVDO machines

Post by rugdoctor »

O.o HD+ too!!!
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Re: Down conversion to 240p using DVDO machines

Post by SGGG2 »

Just bought an HD+. Hope I didn't jump the gun here, I primarily want it for Dreamcast titles, but it turns out the VGA input is a passthrough. Will this still work with VGA input?

EDIT: No worries, I have a transcoder.
Last edited by SGGG2 on Sun May 10, 2015 11:50 pm, edited 1 time in total.
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

No, sorry, you need to go VGA to component first.
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Re: Down conversion to 240p using DVDO machines

Post by RocketBelt »

The VP50 is not playing ball. The TV (lcd) does normally accept 240p over HDMI, and identifies it correctly, from a Wii using the 240p test suite and an HDMI dongle.
But when the VP50 goes below 330 lines the TV gives up with invalid signal. Using PS2 at 480i.
Would be interested to see if it works with a real CRT TV (which I don't have anymore).
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Re: Down conversion to 240p using DVDO machines

Post by Fudoh »

I wouldn't rule out that the analogue output does what the HDMI output can't. For easiest testing you can configure the BNC output as component.
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Re: Down conversion to 240p using DVDO machines

Post by RocketBelt »

It's possible but I won't be able to test that unfortunately. No cables, and the TV doesn't do 240p over component anyway.
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Re: Down conversion to 240p using DVDO machines

Post by Blair »

hey, quick introduction. I'm Blair and I've been messing around with this stuff for a little while (thanks to some inspiration/guidance from Fudoh). I took all those photos during my experimentation with the DVDO units I have on hand.

just wanted to add a few things to the discussion.

these are my current Current resolution settings for the HD+ (this is what's working best so far on my PVM-20L5 and PVM-14m2u)
  • H – shift 42
    H – size 720
    H – front 24
    H – sync 84
    H – back 42

    V – shift 13
    V – size 240
    V – front 13 (10 for the 14m2u)
    V – sync 1
    V – back 22
the VP50Pro might have a DAC limitation and not be able to reach down to true 15khz
Technically, from what I understand 240p-120hz is considered a true lo-res mode, just that it's not compatible with most displays. However it should be compatible with almost any PC CRT monitor that supports 640x480-120hz (like my experiments with the Sony multiscan E400)

it does give gorgeous scanlines, however...

The main downside to this is frame doubling caused by playing 60Hz content at 120hz.

People in the emulation community have been using a technique called "black frame insertion" to get around this with modern graphics cards outputting 240p at 120hz (blanking out the extra 60 frames). Unfortunately there's no way to do this on VP50+CRT at this moment.

however, several new gaming monitors and TV's have been released capable of backlight strobing (another motion technique similar to BFI), independently of the video source. this would give the V50's 240p output perfect motion clarity. (does anybody have one of these monitors to test?)

the frame doubling effect is mostly noticeable in games with lots of fast scrolling (super Mario Brothers, sonic the hedgehog) but I was able to enjoy mega Man and dark stalkers very comfortably.

So it's definitely an option for some people. However when using a consumer TV or production monitor, the older DVDO units seem like better choices (until proper timings can be figured out for VP50s making them output 240p-60hz)
>Oh yeah forgot about that lol useless edg lol
The edge still might be a useful as part of the chain into the older DVD units, basically giving them HDMI compatibility and more ports in general (and possibly better de-interlacing)

In a recent experiment I connected Ps2,Ps4 and Wii U into the DVDO Edge Green, feeding out into the HD+. It works extremely well.

Also, wanted to thank all of you and especially Fudoh, for inspiring me to do any of this.

if anyone has different upscaler models (with custom resolution options) please give those a try at 240p (VP30, Iscan ultra and the Cinemateq PoP II as another user mentioned. it also has a custom resolution option).

if anybody has questions for me, just ask. (image below is from Mega Man 9)

Image
Last edited by Blair on Wed May 13, 2015 7:13 am, edited 3 times in total.
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Re: Down conversion to 240p using DVDO machines

Post by Blair »

Current resolution settings for my HD+ (this is what's working best so far on my 20L5 and 14m2u)

H – shift 42
H – size 720
H – front 24
H – sync 84
H – back 42

V – shift 13
V – size 240
V – front 17 (10 for the 14m2u)
V – sync 1
V – back 22
Last edited by Blair on Wed May 13, 2015 6:06 am, edited 1 time in total.
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Re: Down conversion to 240p using DVDO machines

Post by SGGG2 »

Code: Select all

     H – shift 55
     H – size  640
     H – front 21
     H – sync  62
     H – back  55 
     V – shift 20
     V – size  240 
     V – front 19
     V – sync  6
     V – back  20
Fudoh, my XRGB-3 loses the signal with these timings. Any suggestions?
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