direct_video, ypbpr, and hdmi_limited

Discussion about displays and related hardware including MiSTer filters and video settings.
bry111
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direct_video, ypbpr, and hdmi_limited

Unread post by bry111 »

I have a HDMI -> VGA adapter which works with MiSTer.ini setting direct_video=1, but appears to only support limited range. When trying to output to a CRT via component video (so, ypbpr=1, composite_sync=1, and a diode+resistor to get sync-on-green/Y), the hdmi_limited setting appears to have no effect. Or if it has any effect, it is too subtle for me to notice.

But then out of curiosity I tried to output to the same CRT through an external RGB to component transcoder (so, ypbpr=0, composite_sync=1, and a resistor to knock down the sync voltage). With this setup, hdmi_limited appears to work as expected and setting it to 1 or 2 allows me to distinguish more columns of the SNES 240p test suite's color bars test pattern from the background than hdmi_limited=0 with all other settings the same (and all of the columns could be distinguished if I crank up the CRT's brightness setting enough).

Is this expected? It's good enough for me since I do have an external transcoder, but it was a bit surprising that there was a difference.
ash2fpga
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by ash2fpga »

From what I understand, most of the HDMI to VGA adapters are fairly low-end devices (e.g., mostly 6bpc, which appears fine for most retro gaming). I would not be surprised if they were also mostly "limited" to limited range.
bry111
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by bry111 »

Oh, for sure, my adapter is definitely a low-end device, no question. Plus, maybe sending YPbPr though such an HDMI to VGA adapter is too much of a hack to expect it to work well, I'm not sure.

I'm mostly just curious whether the hdmi_limited option should do anything when ypbpr is set. Is it an RGB-only option?
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ioev
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by ioev »

I'm curious about this as well. I have the exact same setup and settings as you, and my blacks seem extra black and the picture looks overly bright (compared to other component signals I have connected.) I've tried all the hdmi_limited settings, and they don't seem to cause any change.

I'm using this adapter:
https://www.amazon.ca/Rankie-Adapter-3- ... B00ZMV7RL2
paulbnl
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by paulbnl »

The ypbpr setting overrides the hdmi_limited setting so it has no effect if ypbpr=1 & direct_video=1.

Try this SNES core. It has corrected coefficients for SDTV YPbPr for better colors and it should be less bright.
https://drive.google.com/file/d/1SwHUEA ... sp=sharing
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jrronimo
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by jrronimo »

paulbnl wrote: Thu Nov 26, 2020 1:01 pm The ypbpr setting overrides the hdmi_limited setting so it has no effect if ypbpr=1 & direct_video=1.

Try this SNES core. It has corrected coefficients for SDTV YPbPr for better colors and it should be less bright.
https://drive.google.com/file/d/1SwHUEA ... sp=sharing
Woah, did you make this? I've been having some troubles with component video in general (consumer grade CRTs won't sync until there's a bright screen is most cores except NES). Are the coefficients that were corrected for this the same values in other cores?

I'll be testing this out as soon as I can!
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by paulbnl »

Those coefficients are only used with direct video with HDMI->VGA adapter so they won't help with the IO board.
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jrronimo
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by jrronimo »

paulbnl wrote: Mon Dec 07, 2020 8:22 pm Those coefficients are only used with direct video with HDMI->VGA adapter so they won't help with the IO board.
I've just been hoping that there's a solution that can be applied to the issues I'm seeing with my IO Board. Oh well!

For what it's worth, I tested it with a Moread HDMI to VGA adapter (I set ypbpr=1, direct_video=1) and the OSD won't display when going through that adapter, so it probably wouldn't have helped me anyway.
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by paulbnl »

jrronimo wrote: Tue Dec 08, 2020 9:29 pm
I've just been hoping that there's a solution that can be applied to the issues I'm seeing with my IO Board. Oh well!

For what it's worth, I tested it with a Moread HDMI to VGA adapter (I set ypbpr=1, direct_video=1) and the OSD won't display when going through that adapter, so it probably wouldn't have helped me anyway.
Did you use the mod linked above to add Sync on Green to the VGA adapter? It is required for Component. You also need composite_sync=1.

If Component from your IO board is not working and you prefer the IO board then I think you need an external RGB to Component converter like this: https://www.retrotink.com/product-page/rgb2comp
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jrronimo
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Re: direct_video, ypbpr, and hdmi_limited

Unread post by jrronimo »

paulbnl wrote: Tue Dec 08, 2020 10:27 pm
jrronimo wrote: Tue Dec 08, 2020 9:29 pm
I've just been hoping that there's a solution that can be applied to the issues I'm seeing with my IO Board. Oh well!

For what it's worth, I tested it with a Moread HDMI to VGA adapter (I set ypbpr=1, direct_video=1) and the OSD won't display when going through that adapter, so it probably wouldn't have helped me anyway.
Did you use the mod linked above to add Sync on Green to the VGA adapter? It is required for Component. You also need composite_sync=1.

If Component from your IO board is not working and you prefer the IO board then I think you need an external RGB to Component converter like this: https://www.retrotink.com/product-page/rgb2comp
I missed that I needed to do the Sync on Green mod, whoops! I'll see if I can do that easily enough. I thought I tried composite_sync=1, but I might be misremembering. But that might be irrelevant since I didn't do the SOG mod.

I don't think I'll go the route of a retrotink -- although NES on Component looks incredible on my MiSTEr, I can handle using "only" S-Video for Genesis, SNES, GBA, etc. Much easier on the wallet that way, haha.

Thanks for your help and thoughts!
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