CurtPalme.com Home Theater Forum

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6319 Location: Australia

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

Ok that is your opinion. Please use quotes from things I realy said somewhere if you are critisising me. I am also still waiting for proof that your Max does 150MHz Smile

Now please on topic again.

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

removed

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

Is it possible for a moderator to move the off topic part to the off topic forum?

**kal** · Posted: Fri Dec 11, 2015 2:19 pm Post subject:

ElTopo · Joined: 07 Nov 2006 Posts: 1608

Back to the topic Exclamation

I my opinion the next gen blu ray will look awesome on a CRT.

HDMI 1.4 supports 4K

http://www.hdmi.org/manufacturer/hdmi_1_4/4K.aspx

lydmann · Joined: 12 Aug 2006 Posts: 56 Location: Norway

ElTopo · Joined: 07 Nov 2006 Posts: 1608

That is what i wanna hear !

What have you seen ?

- more image punch
- less video noise

ElTopo

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

It seems the new 4k is 2k at most because the processing is done at 2k.
http://www.highdefdigest.com/blog/ultra-hd-not-always-4k/

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

mp20748 · Posted: Sun Jan 17, 2016 12:43 pm Post subject:

Interesting read on this for sure.

Here is what we were told at Barco Tech training in California about three years ago when they were talking about their very large 2K cinema projectors:

Copied from the previous link:

ecrabb · Posted: Sun Jan 17, 2016 5:17 pm Post subject:

Wow, I couldn't possibly disagree with that any more, Mike.

In my old room, I sat about 10 feet from an 8-foot wide 1.78 screen. Even with my JVC RS45 (which has an excellent fill rate), I could easily see pixel structure if I looked at small, fine details like a space ship or planet in the distance, or end credits. Anything small and high-contrast made pixels extremely obvious.

The situation would have been exacerbated much worse when I went to a 10-foot wide scope screen as I had planned. If I hadn't sold my house, I was going to a scope screen, and the only way I could have done it would have been with either a JVC with eshift3 or a an actual UHD projector.

The information from Barco isn't just misleading, it's simply factually inaccurate. it sounds as though the individual who wrote it has no deep understanding of the subject matter at all. Whether the eye can resolve pixels or the additional resolution isn't just about the size of the screen; it's the size of the screen *combined* with the viewing distance. It's the viewing angle, not the screen size. It doesn't matter whether it's a 10-foot wide screen viewed from 10 feet, or a 60-foot wide screen viewed from 60 feet. 1080p isn't adequate for either. With CRT, 1080p is great even at large viewing angles due to the masking effect of a lower MTF. But with a super-sharp digital, 1080p is noticeably inferior to UHD or 4K at the typical immersive viewing angles many enthusiasts enjoy.

Cheers,
SC

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

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

I'm not going to jump into the question (maybe argument) about whether or not the eye (and brain) can resolve more than 1080p in a typical home theatre environment, but I will note that if you think you're seeing pixel structures, I suggest you look directly into the lenses of your CRT projector while the movie is running and you will often see compression artifacts (blocking, etc) clearly visible, most especially in the blue channel, some in the red, and least in the green.

If, due to compression limitations, we're not even coming close to seeing full resolution HD, then there's obviously considerable room for improvement in regular HD viewing.

It's certain that the highest model CRT projectors are capable of considerably better than 1080p. The Cine 9 is factory rated for 3200x2560.

3840x2160 is the native resolution of full 4K.

So the Cine 9 is capable of 83.333 percent of the H resolution and MORE than 100 percent of the V resolution of 4K, and when you count the need to squeeze the raster vertically to the 1.78 aspect ratio of native 4K, then you might start losing a bit of vertical definition. In theory, that'd be 1797 lines when squeezed, and attempting to get more would start leading to scan line merging.

Bandwidth-wise, it's really close, with the Cine 9's resolution working out to 8.2 megapixels per frame, and 4K taking up 8.3 megapixels per frame.

So, apparently the Cine 9 has the raw bandwidth capacity to handle full HD. And it has the scan rate capacity.

The numbers are there. They add up.

The Cine 9 is a 4K (theoretically) capable CRT projector. It may not fully resolve 4K but technically it can do it.

What else might do it?

A modded 9500LC with LUG tubes MIGHT come close, with the right mods to the video chain. (What's Mike's state of the art VIM and neck card mod package delivering now, anyway?)

Lenses...I think I've previously established that the highest grade lenses are 4K capable or close to it. Let's do the math.

We have an assumed 4 inches of vertical CRT phosphor area to work with. Or, let's just call it 100 millimeters instead. (25.4 millimeters per inch.)

The HD10GT17 is rated to resolve 12 line PAIRS per millimeter. Multiply by 100, and you have 2400 line resolution capacity out of a GT17.

For 4K we need to resolve 2160 lines.

We've got it.

Even the regular HD10 is rated for 10 line PAIRS per millimeter, giving you 2000 lines out of a 10cm height raster, which is pretty close to the 2160 we need. It's within 10 percent.

And then there are the "special" lenses that are even sharper with higher resolution ratings.

The numbers say 4K is within grasping distance for the best 9" machines. If they have the video bandwidth.

And let's not forget, even if we can't quite make all of 4K, would you be happy with 4K downscaled to say, 3K or 2.5K? Sure, I think you would.

For full 4K uncompressed video, you'd need 497 MHz video bandwidth, NOT counting overhead for the retrace period, assuming a 60 Hz refresh rate.

Realistically speaking, we can handle a certain amount of compression and not notice it much. Let's assume 50 percent, which I think is a reasonable number.

We're now looking at a bandwidth reuirement of 250 MHz plus overhead.

That's also within reach for the best projectors, with modded video chains as needed.

The truth is that while the potential market is very small, the best 9" CRT projectors should be able to approach, if not actually achieve, a well resolved 4K picture.

So...Mr. Moome, we need UHD HDMI input cards. Please begin the development process right away. I wish to reserve my place in line for the Marquee version card.

mp20748 · Posted: Sun Feb 14, 2016 2:56 am Post subject:

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

As I read the HDMI 2.0 specification, the max bandwidth carried on HDMI 2.0 is 297 MHz. So, 300 MHz video bandwidth is the point at which we have enough for 4K as of the 2.0 specification.

That is within reach. For the entire video chain.

I also note that the spec is for 24 FPS video. To get 30 FPS I must assume 3:2 pulldown and repeated frames if you choose to go with a higher frame rate.

Of course we do know that 30 FPS (progressive scan) is flicker city on a CRT projector. So that has to be dealt with. I don't claim to know enough about how this affects bandwidth requirements to comment on it.

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

One should explain to me why to mix the bandwidth and pixel clock terms, they are not the same!

Do you have a CD player? The sampling rate there is 44.1kHz, yet the maximal output freqency is 22.05kHz -everybody knows, no one complains about it.
Same with the video: at 297MHz pixel clock (sampling rate) your maximal signal output is a 148,5 MHz sine, so if you can resolve that please don't claim it as 300MHz bandwidth.

mp20748 · Posted: Sun Feb 14, 2016 9:26 am Post subject:

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

Just devide by 2 to get the bandwidth that you see in the datasheets of the opamps etc. It takes 2 samples to make a sine. Nyquist sampling theorema Wink

redfox001 · Joined: 16 Mar 2009 Posts: 2251 Location: The Netherlands

The modified neckboard of the marquee that is still a discussion worth. I compared modified neckboards to standard neckboards and surprise the standard neckboards where better and some where a lot better. So I am using standard neckboards in my video chain selected from 9. Strange it is that modifying took the bandwidth down but I have read someone else taking the opamp from the neckboards trying something soldering it back and never getting the performance back. I can not find that thread but some may know. Is it even possible to replace two allready over speced parts with higher bandwidth parts and getting a significant better bandwidth? Very strange, very strange.