Direct Video Questions

[tonyt76]

Has anyone found a HDMI to VGA adapter that does RGB Full 0-255?

Does the (hdmi_audio_96k=0 ; set to 1 for 96khz/16bit HDMI audio (48khz/16bit otherwise) setting work with Direct Video?

[paulbnl]

I have the one from here: viewtopic.php?p=13379#p13379

There appear to be versions with different internals. Someone reported Component was working with Direct Video with theirs but only VGA works with Direct Video on mine.

It has perfect 0-255 VGA output.

The hdmi_audio_96k setting also affects Direct Video.

[shertz]

I bought this one and it works fine for me.....

https://www.amazon.com/dp/B01MS611LJ/

[tonyt76]

I bought this one and it works fine for me.....

https://www.amazon.com/dp/B01MS611LJ/

I have this one as well but it crushes black and does not support 0-255 RGB Full.

[aberu]

I have the one from here: viewtopic.php?p=13379#p13379

There appear to be versions with different internals. Someone reported Component was working with Direct Video with theirs but only VGA works with Direct Video on mine.

It has perfect 0-255 VGA output.

The hdmi_audio_96k setting also affects Direct Video.

Component can work with most of them as long as you mod it according to the MiSTer FPGA wiki article on direct video. I have done the mod (https://github.com/MiSTer-devel/Main_Mi ... pr-signals) by prying open the adapter and connecting the pins as explained internally, on this adapter --> https://www.amazon.com/gp/product/B00SW9JI9A/ - and it wasn't too hard. I use MiSTerAddons.com's VGA to Component cable in conjunction with this.

[shertz]

I have the one from here: viewtopic.php?p=13379#p13379

There appear to be versions with different internals. Someone reported Component was working with Direct Video with theirs but only VGA works with Direct Video on mine.

It has perfect 0-255 VGA output.

The hdmi_audio_96k setting also affects Direct Video.

Component can work with most of them as long as you mod it according to the MiSTer FPGA wiki article on direct video. I have done the mod (https://github.com/MiSTer-devel/Main_Mi ... pr-signals) by prying open the adapter and connecting the pins as explained internally, on this adapter --> https://www.amazon.com/gp/product/B00SW9JI9A/ - and it wasn't too hard. I use MiSTerAddons.com's VGA to Component cable in conjunction with this.

Just FYI that DAC has no audio out.

[aberu]

Yup, good to mention that. It wasn't a major priority for me but I think some people have used hdmi audio splitters in the chain before the direct video adapter with success. I vaguely remember someone mentioning it in the discord. I was skeptical but ah well.

[tonyt76]

FYI, the Tripp Lite P131-06N does not support RGB Full 0-255. It fails the Pluge test.

[Fed]

The hdmi_audio_96k setting also affects Direct Video.

Could you clarify how this setting affects Direct Video ? Can it mess up Direct Video compatibility ?
Thanks !

[Kuro Houou]

Thought I would post this DAC analysis I have been working on here..

https://tinyurl.com/crt-hdmi2vgadacs

Right now I believe there is only one DAC that is truly accurate for the Mister. Based on my analysis only the HDFury3 matches closely to the reference RGB mV levels. DACs based on the AG6200 are the worst, and if you wanted to use limited color space with them you can forget about it. Hopefully this will help some of you. I am continuing my quest for the best DACs for the Mister, so ill keep updating this sheet. But stay away from the AG6200 chip, if you have to use the CS5210. I know the HDFury3 isn't cheap, but I guess you get what you pay for...

[paulbnl]

Could you clarify how this setting affects Direct Video ? Can it mess up Direct Video compatibility ?
Thanks !

Most likely in the worst case the DAC might not output audio.

Thought I would post this DAC analysis I have been working on here..

https://tinyurl.com/crt-hdmi2vgadacs

Right now I believe there is only one DAC that is truly accurate for the Mister. Based on my analysis only the HDFury3 matches closely to the reference RGB mV levels. DACs based on the AG6200 are the worst, and if you wanted to use limited color space with them you can forget about it. Hopefully this will help some of you. I am continuing my quest for the best DACs for the Mister, so ill keep updating this sheet. But stay away from the AG6200 chip, if you have to use the CS5210. I know the HDFury3 isn't cheap, but I guess you get what you pay for...

You seem have the assumption that DACs should output a pedestal with limited range which is wrong. If the DAC properly supports Limited range then 0-255 and 16-235 will result in the same mV output.

[Kuro Houou]

You seem have the assumption that DACs should output a pedestal with limited range which is wrong. If the DAC properly supports Limited range then 0-255 and 16-235 will result in the same mV output.

I am always open to new information but I am not sure what you are saying here. Limited range by definition has black starting at 7.5 IRE, so if you look at an oscilloscope you will see a pedestal that will show a black signal from the source starting at ~50mV. With a broadcast grade pattern generator set to limited range with RGB you will see a pedestal at that level (can also use a PS3 and a good calibration disk with window patterns). With the Mister set to a lower range of 16, regardless if it is 16-235 or 16-255 that pedestal should be the exact same as defined by the reference specifications, all limited range signals should have black starting above blanking/0mV at +7.5 IRE. If a signal does not have that then it is not using proper limited range specifications. That said on the other side, 255 should be the same, so 0-255 and 16-255 should have the same mV at 100 IRE, which my graph shows within about a 1% margin of error which I’ll accept as my error rate for reading my oscilloscope. But again I am open to learning more, if there is documentation that specifies limited range should not start at 7.5IRE somewhere I am open to researching that.

[shertz]

Someone in the MiSTer discord channel posted this...

https://docs.google.com/spreadsheets/u/ ... view#gid=0

Don't know if this helps with your situation.

[Kuro Houou]

Someone in the MiSTer discord channel posted this...

https://docs.google.com/spreadsheets/u/ ... view#gid=0

Don't know if this helps with your situation.

Yeah that’s the sheet I have been working on building out. Just added the HDFuryX4 to that list today.

Hopefully will find more DACs to add to the list.

[paulbnl]

I am always open to new information but I am not sure what you are saying here. Limited range by definition has black starting at 7.5 IRE, so if you look at an oscilloscope you will see a pedestal that will show a black signal from the source starting at ~50mV. With a broadcast grade pattern generator set to limited range with RGB you will see a pedestal at that level (can also use a PS3 and a good calibration disk with window patterns). With the Mister set to a lower range of 16, regardless if it is 16-235 or 16-255 that pedestal should be the exact same as defined by the reference specifications, all limited range signals should have black starting above blanking/0mV at +7.5 IRE. If a signal does not have that then it is not using proper limited range specifications. That said on the other side, 255 should be the same, so 0-255 and 16-255 should have the same mV at 100 IRE, which my graph shows within about a 1% margin of error which I’ll accept as my error rate for reading my oscilloscope. But again I am open to learning more, if there is documentation that specifies limited range should not start at 7.5IRE somewhere I am open to researching that.

Most devices including VGA monitors expect a 0-700mV signal. So a HDMI to VGA DAC that processes HDMI Limited Range correctly should map 16-235 to 0-700mV / 0-100 IRE. Otherwise you will just get grey blacks and darker white shades.

Same thing with HDTVs. They will map 16-235 to 0-100 IRE so with a PS3 for example, if you toggle its output between Limited Range and Full Range there should be no difference in dark and light shades.

I added the limited 16-255 output for the AG6200 DACs to get their output closer to linear 0-100 IRE. It crushes the darker shades with Full range input and it is too dark with 16-235.

[Kuro Houou]

I am always open to new information but I am not sure what you are saying here. Limited range by definition has black starting at 7.5 IRE, so if you look at an oscilloscope you will see a pedestal that will show a black signal from the source starting at ~50mV. With a broadcast grade pattern generator set to limited range with RGB you will see a pedestal at that level (can also use a PS3 and a good calibration disk with window patterns). With the Mister set to a lower range of 16, regardless if it is 16-235 or 16-255 that pedestal should be the exact same as defined by the reference specifications, all limited range signals should have black starting above blanking/0mV at +7.5 IRE. If a signal does not have that then it is not using proper limited range specifications. That said on the other side, 255 should be the same, so 0-255 and 16-255 should have the same mV at 100 IRE, which my graph shows within about a 1% margin of error which I’ll accept as my error rate for reading my oscilloscope. But again I am open to learning more, if there is documentation that specifies limited range should not start at 7.5IRE somewhere I am open to researching that.

Most devices including VGA monitors expect a 0-700mV signal. So a HDMI to VGA DAC that processes HDMI Limited Range correctly should map 16-235 to 0-700mV / 0-100 IRE. Otherwise you will just get grey blacks and darker white shades.

Same thing with HDTVs. They will map 16-235 to 0-100 IRE so with a PS3 for example, if you toggle its output between Limited Range and Full Range there should be no difference in dark and light shades.

I added the limited 16-255 output for the AG6200 DACs to get their output closer to linear 0-100 IRE. It crushes the darker shades with Full range input and it is too dark with 16-235.

I have to disagree. A DAC should not be converting anything unless I tell it too (as in the DAC would have to have a toggle for that). If I am sending 0-255, the DAC should pass 0-255, if I send 16-235, pass 16-235. Same goes for 16-255.

You calibrate your monitor based on input signal or switch your monitor based on input signal. Your right though in PC monitors are designed with full range in mind, but that doesn’t meant they can’t be calibrated for limited too.

Even if what you said was true, and the AG6200 was trying to automatically convert 16-235 to 16-255, all of its voltage readings were way off!!! So you would want to use it even less in that case. I have yet to see a DAC do what you said properly.