CurtPalme.com Home Theater Forum

Corleone88 · Joined: 09 Dec 2006 Posts: 449 Location: France

I am sure that this subject has been debated but I cannot find a clear answer about it. I was wondering what would be the highest resolution that a BG 1209s can handle with a clean picture with a 16/9 signal at 72Hz?
Theoritically, with 135Mz max horz scan, it can handle 2845x1600p@72. So with a Lumagen which can downscale a 4K signal to a custom res like this one, will the result look good? Or it is better to stay in 1920x1080p with 2K?
Thanks

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Sorry, the path is blocked. No Lumagen scaler that has ever been built outputs scaled analog video above 1080p.

A Lumagen that can take 4K in and downscale to any arebitrary resolution below that AND output it in analog for CRT is a dream. One we may hope for but I wouldn't bet on seeing it at any point. Love to, don't expect to.

You are asking for the same thing I want. Which does not currently exist, unfortunately.

The only way to get higher than 1080p today would be with certain PC video cards that have analog RGB outputs
at very high resolutions. The HIGHEST resolution video cards with analog outputs were some of the last AGP video cards, some actually could be pushed to output 4K. But that doesn't mean they were SHARP at 4K.

Corleone88 · Joined: 09 Dec 2006 Posts: 449 Location: France

Well I forgot to say that my BG 1209s has a hdmi port Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

You'll wan to read this topic.

http://www.curtpalme.com/forum/viewtopic.php?t=34138&highlight=resolution

Your HDMI port won't support more than 1080p unless it's a brand new HDMI 2.0 or greater port,
and as far as I know, nobody yet makes those. Moome MAY be developing one.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

http://screenarchery.wikia.com/wiki/Downsampling_%E2%80%93_A_full_guide_to_achieve_3840x2160_resolution_%E2%80%93_NVIDIA_only

This is relevant and useful as well.

**kal** · Posted: Sat Dec 31, 2016 3:37 pm Post subject:

Like Chris mentioned your HDMI input card (or converter) won't be able to do more than 1080p.

Stick with 1080p.

Kal

Corleone88 · Joined: 09 Dec 2006 Posts: 449 Location: France

Ok thanks

kabuby77 · Joined: 28 Mar 2011 Posts: 147 Location: Italy

There's Matrox M9120 with 2 analog 2048x1536 (85Hz ?) outputs. Drivers support edge blending.
3840 x 1536 -> 2.5:1 AR
Barco's can handle it!

RaWsHaRk · Joined: 01 May 2009 Posts: 131 Location: Finland

with computer that res is no problem and it doesnt have to be ancient agp card. I dont have my crt setup and wont have for a long time but clear pic from the computer really wont be the problem

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Yes, there's still a problem with resolution. Just because the card can be overclocked to give 4K that doesn't mean it can RESOLVE 4K.

The problem is one of analog bandwidth and how it relates to the most critical component of the video card that determines what resolution is actually RESOLVABLE.

The fastest video cards use 400 MHz RAMDACs. Assuming you overclocked one all the way to 500 MHz on the RAMDAC and what you end up with is not more than 250 MHz video bandwidth. (Two clock cycles per pixel is the best case scenario, there is no way around this simple fact. )

True 4K requires SIX HUNDRED MEGAHERTZ of video bandwidth. (60 Hz refresh rate assumed.)

You'd need 1.2 GHz RAMDACs.

A lot of cards have dual RAMDACs. Basically all the high end ones. But I don't believe that they allow both RAMDACs to team up on the output to one ANALOG display. If they did, then your overclocked pair could give you 500 MHz of resolution bandwidth, which is awesome but still short of 4K's requirements.

But there isn't a projector in the world whose internal video chain is capable of much more than 300 MHz. Mike Parker claims to have hit a bit over 300 MHz with highly modified Marquee video circuits, but I have no technical details on that or independent laboratory verification of that claim. It's well above any "standard" HD requirements, though.

You could have a resolution of 10,000 x 10,000 and it's not going to give you any more actual image resolution quality than your bandwidth limitation dictates. The higher frequency details will simply not be rendered.

The reason behind at least trying this with an older AGP video card is that some AGP cards allowed higher resolutions to be generated back in the days before HD standards became universally adopted in the video card industry. While 1920x1600 is the max that is supported in HD, a lot of cards could be pushed BEYOND 2048x1536 and in fact I did that myself.

I used to have some very nice Sony monitors that were capable of better than 2048x1536 (which is QXGA) and I once set out to find out the ultimate maximum stable resolution I could push out of them using the Nvidia custom resolution tool.

I don't remember the exact numbers but I believe I was able to hit something like 2406x2009. Pretty impressive, but still a far cry from 4K.

But the thing is, there are cards that are KNOWN to be able to be pushed even farther past QXGA. And the ones that are best for that were being made at the end of the AGP era. There may be some that are early PCI-E.

As I recall, the Nvidia 9500GT range is a particularly good card for this. Coincidentally I got a free one today. I will be testing it, and if it delivers what I want then it will become part of my projector limits testing projectd.

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

I believe most video cards only top out at 400 Mhz ramdac. Which Sony monitors did you have? I still have my GDM-C520K and GDM-F520, and I believe (sans the GDM-FW900 - may it rest in peace Sad

) these were as high as they went. For grins, I can try and push the F520 as high as it will go and see what happens. Very Happy

It "officially" tops out at QXGA at 80 hz or 85 hz I believe. I think in this case I'll be limited by the video card's bandwidth.

You know - Matrox (or am I thinking someone else) had some really highend analog outputs - on par with signal generators, or so I've read. I wonder if there are any legacy models out there that will pump 4K through analog?

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I used a pair of GDM-5410s. There was actually one other high spec flat faced Sun monitor with a nearly all purple case that I had,
but I can't remember its part number. I only had one of those at a time. They definitely could handle 2048x2048 (I have a Sencore monitor analyzer that goes that high) but that was a bit much for the dot pitch on those monitors.

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

Yeah, most likely they were 0.24mm, which was the standard for those monitors back then. Only thing tighter was the F500R and F520, which were 0.22mm. The difference isn't that dramatic. Tighter dot pitch just means that you can keep climbing a little higher with text being readable. 2048x1536 @70 hz is pretty crisp on the F520. On my other one - (0.24mm pitch) not so much. Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

What's interesting is that DCI 4K at 24 FPS comes in under 300 MHz bandwidth.

Unfortunately this isn't really viewable on CRT. We have to use pulldown to get to a non-flickering refresh rate and there goes the bandwidth savings.

If I can find my DVI to RGB breakout cable I'll be able to play with custom resolutions on the projector as soon as I want to. Maybe even tonight. NO guarantees of that, though.

kabuby77 · Joined: 28 Mar 2011 Posts: 147 Location: Italy

There's no point in trying to bring out 4k from a single projector.
CRT are born for 4:3 and there you have the best performances of tubes and electronic.
1920 x 1080 = 2M pixel
2048 x 1536 = 3M pixel
I know many with 9" can run FHD with 72 or 96Hz, it is the same pixel rate of QXGA@60Hz or 48Hz

**AnalogRocks** · Posted: Sun Jan 15, 2017 6:37 am Post subject:

ElTopo · Joined: 07 Nov 2006 Posts: 1608

You need two 1209s if you wanna do 4K

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Even then with 2 projectors, assuming you have a 1080p limit on each projector, 2 projectors does not equal 4K.

4K is FOUR TIMES the pixel count of 1080p. Twice as many horizontal and twice as many vertical pixels.

What's interesting, though, is that the HDMI 1.3 specification formally supports resolutions of up to 2560x1600 at up to a 75 Hz refresh rate.

So that begs the question: If we have an HDMI 1.3 spec input card in our CRT projectors, and we connect a 4K player
via HDMI, will this combination allow us to choose a resolution beyond 1080p and up to 2560x1600?

It may be that the answer to our question, the search for higher resolutions and more picture detail, is literally plug and play
with off-the-shelf equipment available today.

So is there someone here with a true 4K player, with 4K movies, and a CRT projector with an HDMI 1.3 or 1.4 spec input card that can explore the available output resolutions and report back?

thewolfman · Joined: 28 Mar 2011 Posts: 1311 Location: Sweden