Should I upgrade Barco Data 808s to Sony VPL-1292QMG in order to run 1080P for Hidef?

Discussion in 'Displays' started by Johnny G, Jul 20, 2004.

  1. Johnny G

    Johnny G Supporting Actor

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    I'm really happy with my 808s but I have the chance of a 1292 & I'm not too sure about the resolution needed when HD-DVD/Bluray come out.

    I currently have it set at 1280 x 720 (running TheaterTek for DVD) and I was told that the Sony can run at 1080P so it will take Hidef.

    Does that mean that my 808s won't run at a high enough resolution for HD-DVD/Bluray and therefore I'll have to scale it down?

    Sorry if this question sounds dumb but I had the projector/HTPC set up for me & know very little.
     
  2. ChrisWiggles

    ChrisWiggles Producer

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    The issue here is more the resolving capabilities rather than the actualy resolution input capabilities. I don't think the 1292 can really resolve 1080p, though I am pretty sure that both the 1292 and the 808 can input a 1080p signal. I am not using my G808 at the moment, so I've not tried it specifically. Regardless, I wouldn't really worry about this issue at this point.

    If you need a lot more in-depth stuff, read up at the CRT forums at AVS. There are other issues for HD-DVD and CRTs such as HDCP, etc etc.

    But I wouldn't fret, you have an incredible setup.
     
  3. Johnny G

    Johnny G Supporting Actor

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    Thanks Chris, you've made me feel a lot better.

    I've tried to read up at AVS but it all goes over my head. Like I said, I don't understand the techno babble, I don't understand what the difference between resolving capabilities & resolution input capabilities but I trust what you're saying is my Barco should be able to display Hidef in a similar way but not quite as good as a 1292.

    Please educate me if I'm wrong.
     
  4. ChrisWiggles

    ChrisWiggles Producer

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    I'm not too familiar with the 1292 and it's resolving capabilities, but I'll clear up your confusion:

    There are two things going on with CRT projectors, which make them (among many other things) somewhat more confusing than dealing with digital projectors.

    As an analogy, a digital projector, such as a DLP or LCD has panels with fixed, defined numbers of pixels. It displays everything with those pixels, so all the video inputs need to get scaled to exactly that resolution, which is the "native resolution" of the display. You can often feed higher, or lower resolutions, but they get scaled to the native resolution, be that higher, or lower than what you are inputting. With a digital projector, you can never go higher than the native panel resolution.

    What is different about CRT, is that there is no "native resolution." Rather, it's what can be properly resolved.

    Let me explain:

    CRTs usually won't have any type of scaling, so what you feed it is what is displayed, and your only technical limit is the electronic input capabilities of the projector. Your *resolving* capabilities is how many scanlines you can squeeze onto the phosphor without overlapping them too much. Too few scanlines (too low a resolution) and there will be gaps that you can see. Too high a resolution, and there will be too many scanlines that are being displayed, and they will overlap, which will soften your picture. The question then arises, how do you know that number of scanlines which can be properly resolved? You can't really be sure without experimenting in your setup, because it depends heavily on how tightly focused the electron beam is in your projector. The tighter you (or your setup tech) gets the beams focused in the tube, the smaller the scanline size, thus the more you can properly resolve.

    So, with an 8incher like that barco, you'd probably be shooting for something like 720p in a 16:9 frame, or like 960p in 4:3, roughly. Again, this will vary depending on how good the setup is done on the beam. You can feed much higher resolutions to this projector, but again, it will drive the electronics hard, and you will soften the picture slightly because of overlapping scanlines.

    What is listed often as the resolution input capabilities with these projectors is merely the electronic input, i.e. signals it can display, but as explained, not properly resolve without overlapping the scanlines a lot. For instance, my Marquee 8500 uses identical tubes as your barco 808, and gets about the same beam focus, but can be fed even more ridiculous resolutions of 2500x2000. But there is no way that this will be properly resolved in these 8inch tubes. I haven't gotten my G808 setup so I can't speak from my own experience how high you can go with an 808, but 720p 16:9 or 900 lines or so 4:3 is roughly the forum consensus. Hope that gets you at least asking the right questions!

    [​IMG]
     

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