CurtPalme.com Home Theater Forum

[scottatl]

I know a lot of folks think the 3D is a gimmick, but it should be fun. I have read some threads on if HDMI 1.3 will be able to do it, but is seems it is one of the key changes for 1.4. Years off until mainstream, but I hope a few of our inventor friends are already thinking of it.

What do you all think of 3D on CRT?


3D Over HDMI
The 1.4 version of the specification will define common 3D formats and resolutions for HDMI-enabled devices. The specification will standardize the input/output portion of the home 3D system and will specify up to dual-stream 1080p resolution.

[cmjohnson]

The highest end CRT projectors undoubtedly have the bandwidth required. If we just get Moome (or whomever) to come up with a new 3D VIM card, and the frame rate is within limits, we'll have 3D soon.

I'm guessing that the default for 3D at 1080p will be 24 FPS per field. Total bandwidth will be 1080p/48, which is no challenge, as most
Blu-Ray players default to 60 FPS in 1080p mode. (Or at least Sonys do.)

I'm not the guy who's going to be engineering the 3D players or glasses for home use, but if I were to do so, here's how I'd do it:


The player comes with an IR emitter (either on the front of the player or a small remote one connected via a cable) which is used to
send a sync signal to the glasses, which are wireless, battery operated, operate on the LCD shutter principle, and have an IR receiver
in them for receiving the sync pulses.

The player also includes a delay adjustment menu which adjusts the timing of the emitter sync pulse. It also includes a test pattern
which you use with the delay adjustment until the image has the correct 3D effect and it's clean. This is necessary because every
TV has a processing delay, and it's not the same from one set to another. So it will be necessary to trim the timing of the glasses
in some way. Once the setup is complete, the glasses only get the occasional sync pulse to alleviate any possible drifting problems.


That's how I'd do it. I can't speak for how it WILL be done, though, but frankly I'd expect someone to do it just like this.

Too bad I can't implement it myself, because it's certainly a patentable principle. But if you can't make it, you can't patent it. I don't
have the skills or resources to bring it to reality.




CJ

[Nashou66]

I heard they need 120hz refresh rates Chris. if its a single PJ system then only a blend set up will be able to do it, on my Tv-ones i run 1064x800@72 to each PJ, i have tried that res at 96 and 120 and both are capable but the 120 is harder to get fully resolved, maybe with MP vim it might be doable or after I do some work on it, but it definitely a nice pic and super duper smooth pans. Right now both PJ's are stock except for the CMM which I had to modify.

Athanasios

[cmjohnson]

At 1080p x 120 Hz, you'd need a horizontal scan rate of 130 KHz, roughly, and a total video bandwidth of about 375 MHz.

I think that we may have to settle for 1080i x 120 Hz instead. This would still push the bandwidth requirement but would fit in the scan
rate capabilities, anyway.

So who's good at redesigning the VIM and neck cards for 400 MHz bandwidth?


I've been trying to find the actual specification technical data for 3D Blu-Ray. So far I haven't actually found it but I have found a
reference that says it only supports 24 FPS per channel. If that's true, we won't have any problems.


CJ

[mhalsan]

That would work. There might be an issue with flicker due to 24 fps per eye, but that'd be a subjective decision.

There is an article on the web about a Mitsubishi 3D adapter, presumably for their own sets, but if it uses the method described above, perhaps we can adapt it for our equipment.

http://www.twice.com/article/442871-Mitsubishi_Unveils_3D_Blu_ray_Adapter_For_Legacy_3D_Ready_Sets.php

Thanks, Mark

[Mr. Green]

As I posted on the other 3D thread. Here's a link for you...

http://www.letsgodigital.org/en/24286/blu-ray-3d/

[Boilermaker]

Because of the extremely high bandwidth requirement, I just can't see this working with any crt setup except a blend.

I don't think that using an interlaced signal to reduce the bandwidth will work as the second 1/2 of each field would interfere with each other. I think that a progressive signal is necessary.

CJ - I agree with your "proposed" design. I wonder if there is enough light output from any display device in the infra-red range for them to super-impose the synch signal with the video? It sure would make it easy.

I'm hoping that all I will need to make it work with my blend is a Moome box that will give the 3D BD player a proper EDID to send the 48hz 3D signal. I.m excited about the possibilities.

Athanasios - I haven't had the time to try 120hz refresh like you have. What do you think of the results?


Bob

[cmjohnson]

In the theater, 24 FPS has been the standard forever. Does flicker really bother anyone in the theater? I think that dual 24 Hz channels would be quite tolerable.

I will say that when I saw Avatar in 3D, I did see obvious evidence that each channel was operating at half the framerate of the full signal.
In fast motion sequences this was pretty easy to spot but I didn't find it annoying.

If 1080p60x2 is too much to handle, 720px60x2 should fit within our bandwidth limitations with no problem, for the better projectors,
anyway, and there's nothing wrong with a good 720p picture.

1080i with the interlaced fields each being the separated channels, at anything over a total framerate of 60 Hz, should also be acceptable.


My belief is that the 3D-capable players will allow selectable output resolutions and framerates, just as any 1080p capable Blu-Ray
player allows you select 1080i, 720pi, and 480p and 480i if you wish to. It makes sense to be able to deliver a reduced quality 3D
image to the customer, and get him wondering how much better it would be if he went out and got a new set that could take the
maximum quality version of the signal. Good sales tool. And remember, it's ALL about sales.


CJ

[Boilermaker]

[cmjohnson]

The prospect of hotrodding the complete Marquee video chain up to a system bandwidth of 375 MHz is daunting if not actually terrifying. But that's what the Extron bandwidth calculator says would be required for dual channel 1080p at 60 Hz per channel.

I'm just hoping that when 3D blu-ray machines come out, they can run 3D at LESS than top resolution and framerate. I'd be inclined to
believe that they can do so.

For the vast majority even of CRT enthusiasts, the option to blend two projectors is no option at all. It's not going to happen.

I think that I might be able to pull off a side by side stack in terms of the physical requirements, but I can't afford another 9500LC with perfect tubes, MP Gen 2 mods, Advanced Frankenyokes, HD10Fs, and all the other goodies that go along with it.

Blends are an unrealistic option for most of us. Frankly, the best way I could do a blend is to get a second DLP lens and run the pair of
Barco SLM R6 3 chip DLP units together, that I have in my garage at this moment. Turn the entire garage into the home theater.
But even though I have the projectors, it's still unrealistic.


CJ

[CIR Engineering]

I talked to Jim Peterson of Lumagen and also Mike Parker a few days ago specifically about 3D on CRT. It looks like BD 3D will be 1080p 48Hz. Digital 3D sets will then internally multiply the input frequency to either 120Hz or 240Hz.

What Mike Parker suggests is that we shoot for 1080i 120Hz for 3D on CRT. This should provide a similar look to 1080p 60Hz (same bandwidth), but also be an even multiple for 3D applications. Jim says the next Lumagen Radiance processor will be HDMI 1.4 compliant for 3D. Lumagen also told me they are planning to support 1080i 120Hz for 3D on CRT So theoretically, if your projector can run 1080p 60Hz, it should be able to also run 1080i 120Hz.

Also, it looks like we may be able to do this with our existing input devices from Moome and HDFury.

One thing that concerns Jim though is the slower than digital decay rate on CRT's. He thinks this could be an obstacle because 3D needs very fast response on/off.

We'll see...

craigr

[cmjohnson]

Incidentally, I read about how 3D is to be implemented, using shutter glasses and an IR transmitter. Just as I predicted.


CJ

[mhalsan]

I'm going to have nvidia's 3D kit by next weekend. Their literature claims compatibility with CRT at 100Hz or higher. I'll let you know how it goes.................We'll see.

I'm betting the phosphor lag is the biggest holdup. I've already tried running at 100 and 120Hz at higher resolutions, there is some resolution loss, but nothing I'd consider to be a deal-killer.

Thanks, Mark

[CIR Engineering]

[CIR Engineering]

[cmjohnson]

What I've read is that the plan is for 3D to be output at 1080p24 x 2. This is well within the capabilities of practically all better CRT projectors. However, some players may have higher refresh rates available, just as some players were built to output 1080p before 1080p was formally adopted as a standard.


CJ

[CIR Engineering]

[cmjohnson]

I disagree that we "need" 60 FPS per image on a CRT projector. I think that 24 might be a bit flickery, but if we got 48 per image, I think that this would be quite satisfactory. However, that would equate to 1080px96, which is still a pretty stiff bandwidth requirement.

I need to drag a PC home, one with a good video card, and start playing around with it. Actually see for myself what 1080px48 would look
like, or even slower if the machine will sync up.


CJ

[Mark_A_W]

[CIR Engineering]