Any HDMI DACs that support low (like 320x240) pixel clocks?

[BazookaBen]

I know this can be worked around by running higher horizontal resolutions, but some games don't stretch properly or don't stretch at all.

Wondering if anybody's had luck sending 240p, 224p, etc., to a DAC and have it display.

[maxtherabbit]

I know this can be worked around by running higher horizontal resolutions, but some games don't stretch properly or don't stretch at all.

Wondering if anybody's had luck sending 240p, 224p, etc., to a DAC and have it display.

Yes, the Portta HDMI to VGA supports it.

https://twitter.com/RabbitMaximus/statu ... 31585?s=19

[orange808]

To what end?

Consoles don't actually output QVGA timings.

[fernan1234]

To what end?

Consoles don't actually output QVGA timings.

Well if it's going from HDMI then obviously it's not a low res console in the first place. And consoles modded for HDMI are usually outputting an upscaled or line-multiplied resolution anyway, so I'm guessing TC has some device that can output both "super resolutions" as well as digital resolutions equivalent to low res consoles.

I've never seen an HDMI-VGA adapter that can't do this. It only passes along the signal. An SD or multisync CRT should handle them without issues.

[ldeveraux]

I know this can be worked around by running higher horizontal resolutions, but some games don't stretch properly or don't stretch at all.

Wondering if anybody's had luck sending 240p, 224p, etc., to a DAC and have it display.

Yes, the Portta HDMI to VGA supports it.

https://twitter.com/RabbitMaximus/statu ... 31585?s=19

How would I find the generic Portta Video Converter in the right picture? Can't seem to tell which it is on Amazon.

[makar1]

The Tendak HDMI to VGA adapter seems to work fine for 240p/480i output from the Time Sleuth to an OSSC.

[BazookaBen]

To what end?

Consoles don't actually output QVGA timings.

Running low resolutions from CRT emu driver over hdmi to standard Def TV. Ultimate goal is to attempt to enable freesync on CRT's. But the games I want to test with don't have a "stretch" mode that works with super resolutions which is making it difficult.

.
I've never seen an HDMI-VGA adapter that can't do this. It only passes along the signal. An SD or multisync CRT should handle them without issues.

My HD Fury Nano GX works at 480i but gives me scrambled picture with 15khz progressive resolutions

[maxtherabbit]

I know this can be worked around by running higher horizontal resolutions, but some games don't stretch properly or don't stretch at all.

Wondering if anybody's had luck sending 240p, 224p, etc., to a DAC and have it display.

Yes, the Portta HDMI to VGA supports it.

https://twitter.com/RabbitMaximus/statu ... 31585?s=19

How would I find the generic Portta Video Converter in the right picture? Can't seem to tell which it is on Amazon.

https://www.amazon.com/Portta-Converter ... 00KW6BXRG/

[BazookaBen]

https://www.amazon.com/Portta-Converter ... 00KW6BXRG/

So did you use this with CRT emu driver? No super resolutions?

[maxtherabbit]

https://www.amazon.com/Portta-Converter ... 00KW6BXRG/

So did you use this with CRT emu driver? No super resolutions?

I've never used CRT emu driver before

I tested it by using the OSSC as an ADC set to passthrough mode with a genesis as the source

I also use it as a DAC for converting GCVideo-DVI to analog and it supports 240p from GBI

[BazookaBen]

What are the sampling rates on the output of the OSSC and the GCvideo though? I don't know if either of those are 1:1.

[orange808]

What graphics card that actually supports CRT emudriver doesn't have native analog output? Freesync is Displayport and that should automatically provide easy access to analog.

Furthermore, what consumer display is going to cooperate with a such a ridiculously low pixel clock? That's about 6MHz.

The OSSC isn't a true passthrough and it already changes the pixel clock. AFAIK, you can't get 6MHz pixel clock QVGA out of the OSSC at all.

Also, how would Freesync work with the OSSC in the chain?

[maxtherabbit]

What are the sampling rates on the output of the OSSC and the GCvideo though? I don't know if either of those are 1:1.

to be completely honest I don't know, they are the only HDMI sources I have that can output 240p

I don't know if they are outputting 858 or 429 samples per line though, extrems probably does

[Unseen]

What are the sampling rates on the output of the OSSC and the GCvideo though? I don't know if either of those are 1:1.

GCVideo always uses a 27MHz pixel clock, with pixel doubling in 15kHz modes, which is signalled as such when Enhanced DVI is enabled. I have tried outputting without doubling and a 13.5MHz pixel clock in the past, but IIRC every device I tested refused to recognize the signal.

[maxtherabbit]

What are the sampling rates on the output of the OSSC and the GCvideo though? I don't know if either of those are 1:1.

GCVideo always uses a 27MHz pixel clock, with pixel doubling in 15kHz modes, which is signalled as such when Enhanced DVI is enabled. I have tried outputting without doubling and a 13.5MHz pixel clock in the past, but IIRC every device I tested refused to recognize the signal.

?

27MHz would be both line and pixel doubled - 13.5MHz would be 858 samples per line with 262 lines, which I assume is what you're saying it outputs when you switch line doubling 'off' for 240p?

unless you're saying it outputs 1716 (luma) samples per line when line doubling is off?

[BazookaBen]

What graphics card that actually supports CRT emudriver doesn't have native analog output? Freesync is Displayport and that should automatically provide easy access to analog.

I'm trying to force freesync on a non-freesync display. In my understanding, this can only be done over the HDMI output. And CRT Emu Driver currently works on lots of GCN cards that don't have VGA out.

Furthermore, what consumer display is going to cooperate with a such a ridiculously low pixel clock? That's about 6MHz.

A standard low-def CRT

Also, how would Freesync work with the OSSC in the chain?

I don't plan on having an OSSC in the chain. Just HDMI>DAC>CRT. I've been able to enable freesync in the driver, and it works when I sent it to a standard LCD monitor (lost sync so I knew it was changing refresh rate on the fly). But when I'm running 320x240 scaled by drivers to 2560x240, freesync isn't switching on for any of the games or demos I've tried. I'm not sure if it's the scaling that's screwing things up, or if it's just the low resolution breaking freesync, or what.

Having a DAC that actually supports low pixel clocks would help me narrow down the problem.

[orange808]

.

Furthermore, what consumer display is going to cooperate with a such a ridiculously low pixel clock? That's about 6MHz.

A standard low-def CRT

I'll try it in a few minutes and let you know. What's "standard"? Are we talking about a PC CGA TTL monitor, "arcade RGB/C64" CGA monitor, multisync monitor, professional video monitor, or a consumer CRT television?

Having a DAC that actually supports low pixel clocks would help me narrow down the problem.

I recall a thread about that at Blur Busters. Most people couldn't get it to work.

Does it work at 480p, 720p, or 1080p?

[orange808]

Nope. Consumer televisions won't take it. Doesn't work there.

Didn't think it would. That's a long way from the standard 13.5MHz.

[BazookaBen]

What's "standard"? Are we talking about...

The 15kHz standard. Currently trying this on a Panasonic TV.

I recall a thread about that at Blur Busters. Most people couldn't get it to work.

Does it work at 480p, 720p, or 1080p?

Not sure if you mean the DAC or Freesync.

I haven't tried Freesync at 480p yet but it was working when I did a quick test at 1280x1024 on the secondary LCD monitor.

The DAC works at 480i, though its a little shaky. 240p gives a scrambled picture. DAC is HD Fury Nano GX.

Nope. Consumer televisions won't take it. Doesn't work there.

Didn't think it would. That's a long way from the standard 13.5MHz.

It works when I send it from the analog output on the GPU. 256x224 even works. So it's not an issue with the TV

[orange808]

What's "standard"? Are we talking about...

The 15kHz standard. Currently trying this on a Panasonic TV.

That television needs 13.5MHz or something close.[/quote]

I recall a thread about that at Blur Busters. Most people couldn't get it to work.

Does it work at 480p, 720p, or 1080p?

Not sure if you mean the DAC or Freesync.

I haven't tried Freesync at 480p yet but it was working when I did a quick test at 1280x1024 on the secondary LCD monitor.

The DAC works at 480i, though its a little shaky. 240p gives a scrambled picture. DAC is HD Fury Nano GX.

I meant Freesync. I'd start with something that should work. That means 480p on a PC VGA CRT.

I have a BenQ HT2150st that accepts just about anything (probably due to Texas Instruments selling lots of DLP data projectors). Feeding 240p through the HDFury Nano GX DAC works just fine.

[orange808]

It works when I send it from the analog output on the GPU. 256x224 even works. So it's not an issue with the TV

Interesting. Does the GPU do exactly what it's told?

Sending a custom timing from the Corio2 fails on my displays. I know for a fact that the C2 does exactly what it's told.

I pulled a QVGA timing from the OSSC github.

[BazookaBen]

Interesting. Does the GPU do exactly what it's told?

Yeah, pixel perfect. Mega Man 9 and 10 look glorious running in their native 256x224 from Dolphin, versus the abomination of 448i when you play them on the Wii.

[BazookaBen]

Feeding 240p through the HDFury Nano GX DAC works just fine.

Wait, so what are you feeding the HD Fury with? A PC sending un-scaled 320x240?

[orange808]

Interesting. Does the GPU do exactly what it's told?

Yeah, pixel perfect. Mega Man 9 and 10 look glorious running in their native 256x224 from Dolphin, versus the abomination of 448i when you play them on the Wii.

It's entirely possible that the pixel clock for that would fall below the minimum and the GPU is tripling "pixels" to handle it. That would invisible to your eye.

[orange808]

Feeding 240p through the HDFury Nano GX DAC works just fine.

Wait, so what are you feeding the HD Fury with? A PC sending un-scaled 320x240?

I can't trust a new PC GPU to do exactly what it's told.

QVGA works with Windows 98/Voodoo 3 3500, but that's direct RGBHV to the projector.

Proper 858x262 240p works chained through the HDFury Nano with the Corio2 750 and OSSC "passthrough".

I haven't tried QVGA through the DAC.

Edit: Also, used a C2-1250 for the QVGA out direct to CRT testing. No DAC involved. Direct analog out.

[BazookaBen]

It's entirely possible that the pixel clock for that would fall below the minimum and the GPU is tripling "pixels" to handle it. That would invisible to your eye.

Maybe, but ever since Windows 10 was released, you have to jump through a lot of hoops to get anything below 800x600 (like installing CRT Emu Driver). And in older Windows like 7, I think the lowest they would let you select is 640x480, even if you created 240p in CRU or something.

So I'm not sure there would be extra work happening in the drivers to support a resolution that the operating system usually doesn't even allow.

[orange808]

One more thing. If I recall correctly, Megaman 9 and 10 on the Wii are unicorns, because they don't use an aggressive flicker filter (or any flicker filter??). That's great news, because they are candidates for "double strike" deinterlacing with an Extron RGB or Corio2.

[BazookaBen]

One more thing. If I recall correctly, Megaman 9 and 10 on the Wii are unicorns, because they don't use an aggressive flicker filter (or any flicker filter??). That's great news, because they are candidates for "double strike" deinterlacing with an Extron RGB or Corio2.

Yeah, I could never get perfect deinterlacing with my Extron RGB's. It seemed there was always like a 10hz jitter where a field would be moved one line up.

I've seen some people get great results with Corio and others get pretty bad results. I guess it takes some homework to know how to get them set up properly to get the 2:1 scaling perfect.

[Unseen]

27MHz would be both line and pixel doubled

No, it's just pixel-doubled.

13.5MHz would be 858 samples per line with 262 lines, which I assume is what you're saying it outputs when you switch line doubling 'off' for 240p?

Correct, the Gamecube uses a 13.5MHz pixel clock for 15kHz modes, so either 858 or 864 total luma samples per line with 720 or less of them outside of blanking.

unless you're saying it outputs 1716 (luma) samples per line when line doubling is off?

Yes, conforming to CEA modes 6/7 (NTSC interlaced), 8/9 (NTSC 15kHz progressive), 21/22 (PAL interlaced) or 23/24 (PAL 15kHz progressive)

[Xyga]

FreeSync on 15KHz CRT has been explored recently @BYOAC, and confirmed not properly working. It can work but most of what you'll get is a shaking and jumping, jerky picture, how much also depends on the display so it's a mess.
Unless a trick is found in the future to actually make it valid, there's no point in bothering with that.

People should just do the usual AMD+Emudriver config, with a HDMI>VGA dongle indeed when it's an AMD without an analogue out.
That at least, even if yet too few dongles have been confirmed 100% ok for the job, is know to work.

PS: Yeah W10 updates can definitely break a CRT_Emudriver config, repeatedly. In any case it's less trouble to use W7 and an older AMD card (up to some R9 that still featured analogue)
Really, a 15KHz emu setup is more at ease on a dedicated PC anyway.