HDMI to S-Video Question for CRT TV

[ctrl77]

Hi guys, I didn't want to sully the "S-Video and Composite Over Component Output! (Custom Cores)" thread so I figured I would post my questions here:

I recently received my DE10-nano and am primarily looking to output to a 27" Sony Trinitron CRT TV via S-video (no component or SCART) and want the best experience possible for playing Neo Geo and possibly a few other consoles. I read through the above thread and the MiSTer CRT Guide and noted the pros and cons of the Analogue I/O board, one of which included "lesser colour depth in some cores" and "lower quality sound output"; considering that those do not sound ideal to me, is using an I/O board still the optimal way to output to S-video?

If I grabbed Antonio Villena's IOUSB PLUS with "112dB SNR audio DAC (PCM5122)" coupled with his VGA to S-Video adapter would that address my concerns with low quality sound output? Or should I wait for something new that's in the wings?

However I see devices out there that claim to do HDMI to S-Video directly, are these alternative options or they won't match the proper input resolutions? Has anyone tried anything like this?

https://www.adafruit.com/product/3537
https://www.amazon.ca/SUNNATCH-Converte ... B096S2KJBH
https://www.amazon.ca/SVideo-Converter- ... B09N1K4QKT

Thanks in advance!

[MikeS1]

Technically if your using s-video and the YC cores through the Analog IO board you get 24 bits color. Since chroma is modulated in the YC module you use all 8 bits for each RGB. But it's also s-video so I can't speak to how much you would be able to tell?

If you see any HDMI to s-video adapters it's going to be prone to scaling errors and lag. You still can use the YC cores or even external encoders out with an HDMI to VGA adapter.

[DevilHunterWolf]

It's best to keep in mind the context of the statements. The analog output from the standard IO board isn't bad quality by any means. But old analog signals are technically inferior in quality to modern digital standards. Of course an analog video signal out the VGA connector is going to be lesser than what's possible with HDMI. And of course analog audio out the 3.5mm jack is not going to be able to match a full size optical audio out in the digital IO board. New technology standards tend to outperform the old. That's just how technology evolves. Now how much technicalities bother you, that's up to your preferences. I've never been bothered by it and the analog quality out of the MiSTer's standard IO board is still leagues better than anything I got out of an original system over composite. It's all an improvement in that context. But if you're going to put it up against some of the best connections of today, it's just not going to match.

For any adapters or cables you look at, make sure they are compatible with MiSTer. MiSTer doesn't always use ports as the standards say it would be used. The big one is the VGA port is which just a common connector the IO board is using. It's not strictly VGA but whatever is programmed to come down the cable which is why it can output SCART, Component, or even S-Video and Composite. But it does mean not all cables or adapters work. For example, the type of VGA to Composite cable we use with MiSTer is meant for projectors or anything that just sends out an unconverted signal. That same cable wouldn't work on a computer and a computer capable cable wouldn't work with MiSTer. Just because a cable or converter claims it can do something, doesn't guarantee that applies to MiSTer. Unless of course it's already been tested with MiSTer or through a trusted MiSTer seller.

[ctrl77]

Thanks for the detailed responses Mike and Devil, so that takes converting straight from HDMI to S-video off the list.

the analog quality out of the MiSTer's standard IO board is still leagues better than anything I got out of an original system over composite

I'm a 'retro gamer' with a Sony Trinitron KV-27V45 and in using some console S-video cables I bought on Amazon for my SNES, Genesis, etc., the picture is amazing - perfect clarity, colours pop, there's no interference, and I can't imagine that the experience would be any better aside from upgrading my TV to a higher end one with component. Even my Famicon disk system is crystal clear with no interference.

To answer your point with "how much technicalities bother you", I can't say that I'm concerned with 'technicalities' as a word but I do want to have the best experience that I can get with the hardware available to us with this project.

So with that being said, it's my hope that I can replicate the quality experience I have with my native consoles on my existing CRT TV and extend that to what I'll be doing with the MiSTer system; I want to have the best video I can get, I want to have the best sound that I can get (most likely through the TV speakers which are pretty good), I want to display the closest approximation of the original aspect ratio, and I don't want to have any lag.

Knowing that I want to have 'the best' visual and audio experience I want to have, would you recommend me purchasing the aforementioned I/O board and adapter? Or should I be waiting for something else on the horizon? Or are there alternatives you might recommend investigating further?

Thanks again, there's a lot of data to consume on this topic and it seems a lot has changed since this project debut, and a lot of the components are outside of my country (Canada) so I don't want to make any mistakes.

[FoxbatStargazer]

The 3.5 audio jack in the analog i/o is both analog stereo audio and mini-toslink digital audio. So you can get the same digital sound out of it if the analog i/o's onboard DAC isn't doing it for you.

I would not trust a generic hdmi->s-video downscaler, those will take common HDMI resolutions down to 480i while adding significant lag, which is not what you want at all. Instead you would use either an HDMI->VGA adapter with direct_video, or just the analog I/O board VGA port. Either attach antionio's whatever s-video adapter to that, or use a breakout vga->component and/or svideo cable with Mike's custom cores.

I think all the nonsense with luma traps and dot crawl is a composite thing, so hopefully quality s-video should be easier to swing.

[shertz]

Buy one of these. Be happy...

https://ultimatemister.com/product/mike ... ive-board/

[rickdangerous]

Buy one of these. Be happy...

https://ultimatemister.com/product/mike ... ive-board/

Thanks for your suggestion, new stock after >1 January.

Happy new year.
Ricardo

[ctrl77]

I'm on the waiting list, thanks gents.

[ctrl77]

I just saw this flowchart posted in another thread and it's super helpful, someone should find a way to link it on the Wiki:
Flowchart of all common MiSTer Video Output Options - viewtopic.php?t=5875

In light of that, I decided to hold off on the I/O board as there are a couple options I can't decide on,

• whether I want to wait for this fancy dual RAM 'ultimate blisster' board for future capabilities:
  https://ultimatemister.com/product/ulti ... sster-kit/
• whether I want Antonio Villena's awesome looking IOUSB PLUS:
  https://www.antoniovillena.es/store/product/iousb-plus/

Instead I figure I'll get the suggested "MikeS1 Y/C Passive Board" VGA to S-Video adapter when it's back in stock then go from there...
https://ultimatemister.com/product/mike ... ive-board/

I was wondering why there were multiple options for these adapters in various stores, either in the Mister FPGA store or on Antonio Villena's site (he's sold out too), so I decided to look before asking and I found this explanation from Mike very helpful thread here:
MiSTerFPGA Y/C Out Module (Direct - S-Video / Composite Output) - viewtopic.php?t=5475

I realize a lot of this is old hat to most of you but I kind of had to hunt around for a lot of this information and so much of the data found on this project is outdated and replaced with new information as it's a steadily improving project with so much community input. Please let me know if you think I'm on the wrong track!

In the meantime I ordered the following two HDMI to VGA adapters as linked on the RetroRGB site:
Rankie HDMI to VGA Adapter with 3.5mm Audio Port, Black - https://www.amazon.ca/gp/product/B00ZMV7RL2
Tendak Active 1080P Female HDMI to VGA Male Converter - https://www.amazon.ca/gp/product/B01B7CEOVK

[C-R-T]

The 3.5 audio jack in the analog i/o is both analog stereo audio and mini-toslink digital audio. So you can get the same digital sound out of it if the analog i/o's onboard DAC isn't doing it for you.

The analog io board doesn’t have a DAC, the analog signal comes out of the DE10 nano.

[thisisamigaspeaking]

The analog io board doesn’t have a DAC, the analog signal comes out of the DE10 nano.

Does it have a DAC for the VGA even? Antonio Villena's board lists one but I don't see anything like that on the parts list for the standard I/O board.

[jca]

A DAC made of resistors.

[thisisamigaspeaking]

A DAC made of resistors.

Aha, looked at the schematic. How does the accuracy of a discrete DAC (or this one in particular) compare to an IC?

[jca]

The more accurate the resistors the more accurate the DAC, the less bits the more accurate.
More info here:
https://www.electronics-tutorials.ws/co ... r-dac.html

[jca]

When used in FPGA projects they usually go to 12 bits (4 bits/color, 4096 colors).
Example: https://digilent.com/shop/pmod-vga-vide ... ics-array/

[thisisamigaspeaking]

So viewtopic.php?t=3865 for example may be a consequence of poor quality components being used, or just outright wrong components? I'm wondering for OP's purposes in comparison to a commercial HDMI->S-Video converter if that will yield better looking results.

Another question I have is why Antonio's analog i/o board has an audio DAC - I guess there is a digital audio signal available on the arduino header?

[thisisamigaspeaking]

Also wonder why Antonio's VGA DAC can be 8-bit... Not that it will matter much for the old systems we are running I guess.

[jca]

The less bits the less colors to choose from and the resistors must be high precision ones 1% for example
For the audio DAC I suppose it is a better one than the MISTer one which is not terrific.

[jca]

Also wonder why Antonio's VGA DAC can be 8-bit... Not that it will matter much for the old systems we are running I guess.

Are you sure of that? I would guess it is the same as MISTer VGA which I think is 18 bits.

[thisisamigaspeaking]

Also wonder why Antonio's VGA DAC can be 8-bit... Not that it will matter much for the old systems we are running I guess.

Are you sure of that? I would guess it is the same as MISTer VGA which I think is 18 bits.

He says it is 8-bit/24-bit.

RGB888 R-2R DAC

So he is finding digital audio and 24-bit color from the MiSTer somehow... Sounds like a nice board, but, not being an electronics engineer or anything, I would rather see an appropriate IC DAC (or DACs) if it is going to be premium quality.

[jca]

So the VGA is 24bits (8bits/color).
For the audio I do not know what is on his board so I cannot comment but I guess it would be an IC DAC.

[FoxbatStargazer]

I thought the 18 bit thing wasn't a limit of the Mister's DAC itself, but of the pin bandwith.

So Antonio can call it an 888 DAC even if Mister never uses it that way?

I know he has done something special with DB9/SNAC but that requires custom cores to use fully.

[antoniovillena]

Hi

Here you have support for RGB888 and mt32pi with second user io:

https://github.com/orgs/MiSTer-Enhanced/repositories

Regards