VGA => composite to a CRT TV without scaling?

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bort
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VGA => composite to a CRT TV without scaling?

Postby bort » Mon Jan 07, 2019 3:00 am

I have a 24" Sony Trinitron TV (NTSC), and I want to hook up my MiSTer to it. I'm experimenting with this VGA-to-composite adapter, rather than using HDMI, in the hopes of reducing the display lag as much as possible. For that reason I would like to avoid using vga_scaler and just have all of the cores output at their native resolutions.

When I hook it up and turn it on, I get this:
Image

Obviously the problem there is that the menu wants to be in PAL mode, so if I replace menu.rbf with Kitrinx's NTSC version it looks much better:
Image

However, if I load any core (NES, Genesis, etc.) it throws off the video refresh and causes the menu to dance around the screen:
Image

I've tried many combinations of settings in MiSTer.ini, but here is what I have currently:

Code: Select all

[MiSTer]
key_menu_as_rgui=0
forced_scandoubler=0
ypbpr=0
composite_sync=1
vga_scaler=0
hdmi_audio_96k=0
keyrah_mode=0x18d80002
volumectl=0
vscale_mode=0
vscale_border=0
rbf_hide_datecode=0
reset_combo=0
dvi_mode=0
video_mode=2
video_info=0
vsync_adjust=1


Is there a way to make the MiSTer output native analog composite video at the right refresh rate? I have been doing lots of reading and experimentation, but so far have not had much luck. Thanks in advance for any help you can provide.

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Mon Jan 07, 2019 5:03 am

The first thing you need to know that MiSTer.ini supports settings per core.
So you can setup menu core to use vga_scaler and specific NTSC resolution.

As for other cores - it depends. If your TV is NTSC-only then you will have problems with some cores.

As for adapter. I really doubt it include any circuit inside. So most likely this adapter is for specific VGA cards supporting output composite and s-video natively. So highly likely this adapter won't work.

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Mon Jan 07, 2019 5:05 am

And generally speaking, main video output of MiSTer is HDMI.
VGA is mostly for debugging and not suitable for normal user. Different cores output different resolutions.

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Mon Jan 07, 2019 5:09 am

bort wrote:I have a 24" Sony Trinitron TV (NTSC), and I want to hook up my MiSTer to it. I'm experimenting with this VGA-to-composite adapter, rather than using HDMI, in the hopes of reducing the display lag as much as possible....

Unfortunately this cable is not appropriate for the MiSTer, the amazon page you linked says:

IMPORTANT Please READ! Before Buying
This item is a VGA VIDEO Card to S Video or Composite TV Adapter Cable
Use it to connect the video card on your computer to a TV input
Your video card MUST be able to support s-Video or Composite out through it's VGA port


MiSTer is not capable to output S-Video or composite signal over VGA. I recommend to use an YPbPr cable intead, if your TV-set has such input. Picture quality will be much better as well compared to composite. Here you can find more info:

https://github.com/mist-devel/mist-boar ... PbPr_Cable

EDIT:
Sorgelig was faster, and he has overtaken me! :D

How others do it :contract: :
viewtopic.php?f=117&t=34955&p=361949#p361949

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Mon Jan 07, 2019 5:32 am

As for YPbPr: MiSTer doesn't require any external circuits in cable. Everything is on I/O board already. So, for YPbPr you can use any VGA-YPbPr cable made for PC.

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Mon Jan 07, 2019 9:40 am

Sorgelig wrote:As for YPbPr: MiSTer doesn't require any external circuits in cable. Everything is on I/O board already. So, for YPbPr you can use any VGA-YPbPr cable made for PC.

I didn't know that, thanks for the clarification!

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Re: VGA => composite to a CRT TV without scaling?

Postby Xtro » Mon Jan 07, 2019 2:47 pm

Would it be possible for the MiSTer to output composite vídeo from a VGA to YPbPr cable? I know this is the worst video quality, but some cores like NES I am used tocomposite video and some games used composite video tricks to show more colors or transparencies . For example Apple II core would benefit from that.

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Mon Jan 07, 2019 4:11 pm

Y channel in YPbPr is actually composite video.
But it's monochrome.

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Re: VGA => composite to a CRT TV without scaling?

Postby orange808 » Mon Jan 07, 2019 7:36 pm

Composite video isn't necessary for Apple ][ color bleeding.

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Re: VGA => composite to a CRT TV without scaling?

Postby bort » Tue Jan 08, 2019 6:47 am

Thank you everyone for providing this very valuable information. Unfortunately my television does not support component video input, but that sounds like the ideal setup so I will start looking to see if I can find one in my local area.

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Tue Jan 08, 2019 1:41 pm

If you want to use the composite input of your TV by all means, I recommend this RGB-to-component converter:
https://www.aliexpress.com/snapshot/0.h ... =502847877
It's relative cheap, and provides an acceptable picture quality. You can switch between NTSC and PAL standards, it works well with MiST cores in 15kHz (scandoubler disabled) mode.

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Tue Jan 08, 2019 1:54 pm

DrOG wrote:If you want to use the composite input of your TV by all means, I recommend this RGB-to-component converter:
https://www.aliexpress.com/snapshot/0.h ... =502847877
It's relative cheap, and provides an acceptable picture quality. You can switch between NTSC and PAL standards, it works well with MiST cores in 15kHz (scandoubler disabled) mode.

Your link is to your order. It's not available to others.

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Wed Jan 09, 2019 5:51 am

Sorry, my bad :oops: I was in a hurry and forgot to logout...

So here's the link:
https://www.aliexpress.com/item/Arcade- ... 4c4dP7CSBR

And as compensation two screenshots...
You do not have the required permissions to view the files attached to this post.

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Re: VGA => composite to a CRT TV without scaling?

Postby bort » Wed Jan 09, 2019 6:12 am

Thank you for the link! Do you have any idea how much display lag this converter adds?

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Wed Jan 09, 2019 10:36 am

I don't know, but it's likely a full analog device without frame buffer, so delay should be minimal. And it's recommended for use with arcade boards, because of this negligible lag is required. It merges the 3 color components (red, green and blue) with sync signals to composite/s-video out, but no digital post-processing (i.e. framerate conversion or upscaling) is performed by the device. Color balance adjustment is analog as well (it uses 3 different potentiometers, one for each component). But I can specify 3 drawback of this board: 1. Lack of casing 2. No PSU, only power cable 3. Needs some hand soldering to connect is to the MiST(es)'s VGA output.

EDIT:
I tested this converter previously, you find my experiences in the MiST topic below:
viewtopic.php?f=115&t=31322&p=339813#p339813

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Wed Jan 09, 2019 5:09 pm

this device doesn't add any delays.

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Re: VGA => composite to a CRT TV without scaling?

Postby digitron » Sun Apr 28, 2019 6:42 pm

DrOG wrote:Sorry, my bad :oops: I was in a hurry and forgot to logout...

So here's the link:
https://www.aliexpress.com/item/Arcade- ... 4c4dP7CSBR

And as compensation two screenshots...


I purchased that converter, thanks for the recommendation. Do you have any info on how you wired it to the Mister or IO board? Thanks! :)
Last edited by digitron on Mon Apr 29, 2019 4:17 pm, edited 1 time in total.

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Re: VGA => composite to a CRT TV without scaling?

Postby Lroby74 » Mon Apr 29, 2019 1:40 pm

Sorgelig wrote:And generally speaking, main video output of MiSTer is HDMI.
VGA is mostly for debugging and not suitable for normal user. Different cores output different resolutions.


So, if i buy a Mister with VGA/RGB addon and using Mist's VGA to SCART cable, i would not able to going to a CRT PAL 15Khz RGB TV like i am already doing now with Mist?

If is in this way, i will think 2 times before buy Mister
8O 8O 8O 8O 8O

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Re: VGA => composite to a CRT TV without scaling?

Postby Newsdee » Mon Apr 29, 2019 2:08 pm

Lroby74 wrote:So, if i buy a Mister with VGA/RGB addon and using Mist's VGA to SCART cable, i would not able to going to a CRT PAL 15Khz RGB TV like i am already doing now with Mist?
If is in this way, i will think 2 times before buy Mister
8O 8O 8O 8O 8O

I think he just means it's not guaranteed to work. Same with MiST really, the signal it sends isn't always standard...

Anyway nobody is forcing you to buy a MiSTer, especially if the cores and features with HDMI is not your thing.

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Re: VGA => composite to a CRT TV without scaling?

Postby Lroby74 » Mon Apr 29, 2019 7:08 pm

Newsdee wrote:Anyway nobody is forcing you to buy a MiSTer, especially if the cores and features with HDMI is not your thing.


No forcing, i would like to have it too for have something new to discover and explorer other than Mist & Mistica, but only is full compatible with RGB SCART on TV PAL connection :angel: :angel:

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Re: VGA => composite to a CRT TV without scaling?

Postby DrOG » Tue Apr 30, 2019 12:33 pm

digitron wrote:
DrOG wrote:Sorry, my bad :oops: I was in a hurry and forgot to logout...
So here's the link:
https://www.aliexpress.com/item/Arcade- ... 4c4dP7CSBR
And as compensation two screenshots...

I purchased that converter, thanks for the recommendation. Do you have any info on how you wired it to the Mister or IO board? Thanks! :)

I wired it to MiST, but pinout is the same...
VGA pin - Function
#1 - RED
#2 - GREEN
#3 - BLUE
#13 - HSYNC/CSYNC
#14 - VSYNC
#5, 6, 7, 8, 10 - Ground

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Re: VGA => composite to a CRT TV without scaling?

Postby digitron » Tue Apr 30, 2019 4:40 pm

DrOG wrote:
digitron wrote:
DrOG wrote:Sorry, my bad :oops: I was in a hurry and forgot to logout...
So here's the link:
https://www.aliexpress.com/item/Arcade- ... 4c4dP7CSBR
And as compensation two screenshots...

I purchased that converter, thanks for the recommendation. Do you have any info on how you wired it to the Mister or IO board? Thanks! :)

I wired it to MiST, but pinout is the same...
VGA pin - Function
#1 - RED
#2 - GREEN
#3 - BLUE
#13 - HSYNC/CSYNC
#14 - VSYNC
#5, 6, 7, 8, 10 - Ground


Thanks!!!!! :)

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Re: VGA => composite to a CRT TV without scaling?

Postby digitron » Thu May 02, 2019 12:13 am

Sorry for all the questions any my noobie-ness but between the converter from Aliexpress and the Mister, is there a way to enable line-doubling on various console cores like SNES, Turbografx16, etc.? My goal is to have it connected via S-video, with that converter to my JVC PVM (which has no RGB), but the s-video quality looks really nice (750 lines).

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Re: VGA => composite to a CRT TV without scaling?

Postby Sorgelig » Thu May 02, 2019 5:13 am

digitron wrote:Sorry for all the questions any my noobie-ness but between the converter from Aliexpress and the Mister, is there a way to enable line-doubling on various console cores like SNES, Turbografx16, etc.? My goal is to have it connected via S-video, with that converter to my JVC PVM (which has no RGB), but the s-video quality looks really nice (750 lines).

S-Video is for original TV signal only (15KHz). So you can't use scandoubler.

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Re: VGA => composite to a CRT TV without scaling?

Postby digitron » Thu May 02, 2019 2:27 pm

Sorgelig wrote:
digitron wrote:Sorry for all the questions any my noobie-ness but between the converter from Aliexpress and the Mister, is there a way to enable line-doubling on various console cores like SNES, Turbografx16, etc.? My goal is to have it connected via S-video, with that converter to my JVC PVM (which has no RGB), but the s-video quality looks really nice (750 lines).

S-Video is for original TV signal only (15KHz). So you can't use scandoubler.


Thank you Sorgelig, can I tell the SNES core to run at 480i?


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