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HDMI / DVI aspect ratios?

Discussion in 'Playback Devices' started by murrayThompson, Oct 28, 2004.

  1. murrayThompson

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    I hope someone can answer my question when using 720 or 1080 on hdmi or dvi.
    I have now tried two projectors and three players and noticed none of them fit the boarders of the 16.9 black masking when on hdmi or dvi. Everything is perfect to the black masking on SAT TV on s video and also perfect when playing dvd through component. The dvd disk menu is perfectly aligned to the black masking and its only when the film starts do I get this problem on dvi and hdmi. As most projector functions cancel out on hdmi/dvi one cant use any overscan.Three players I have tried are pioneer DV S969AVI G , Denon DVD 2910 and Samsung HD747, all players are hdmi/dvi. The projectors I have tried them all on are the new Panasonic 700 and the new Hitachi pj tx100. i have spoken with all the manufactures of the fault and all of them draw a blank. The answer to me is s vid and component should be a bit smaller to match the ratio of hdmi/dvi or the size of hdmi/dvi needs to increase a bit. They have told me I need to just zoom the picture size up a bit on hdmi/dvi to correct the fault but who wants to climb up a ladder everytime you change the imput. The size of the feature film differs all over the place from different disks,sometimes missing a few inches left and right,sometimes just a bit off the bottom. Hope someone out there has an answer to this puzzling question? ps. this is not a 2.35/scope issue of the black bars top and bottom.[​IMG]
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    You just need a projecdtor with several memories so you can save custom picture width and height calibration settings for DVI, HDMI, component, etc.

    It is not unusual for 480p, 1080i, and 720p to not match up when the projector is first taken out of the box and turned on. Also the utilization percentage of the scan line can differ for DVI versus analog even for the same scan rate, giving the effect of differing picture widths.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. murrayThompson

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    Im sorry Allan but Im still not sure what you mean? If you can't change the aspect ratio on hdmi or dvi due to projectors canceling them out, how can you save them in the memory?
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    Are you saying you have no calibration control at all for DVI and HDMI, or is the picture size just slightly different for DVI and HDMI versus component and S-video?

    Even if you have no calibration for DVI and HDMI, you can let those sources set the standard for you (adjust the lens or the screen masking) and then use calibration to get component and S-video to match. Again you need memories (a.k.a. presets) to hold different calibrations.

    Although 1080i and 720p are natively 16:9, 480p and 480i can be either 4:3 or 16:9 and a projector that does not have aspect ratio selections will forever be a pain in tghe a**.

    DVD may use either a 704 x 480 or a 720 x 480 pixel format. This results in a slight difference in width, hidden only byt overscan in the TV.
     
  5. murrayThompson

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    Thanks again for your help but things are still not working.My projector does have ratios (many) but they wont work on 1080i or 720p as the manual says. Its the overscan that the projector doesnt have and thats what I would need to correct the slight miss from the edges Im getting on HDMI. Im sure if it was hooked up to my Plasma it would not happen, yet it doesnt have HDMI. The memories on my projector only save things like colour/contrast etc. Its the fussy edges Im seeing that would normally be hidden on the overscan and only on HDMI.
    Can the overscan on the projector for HDMI be increased by asking Pansonic to do it internally in the machine?
     
  6. murrayThompson

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    Forgot to say,,,
    The following aspect ratios work in HDMI 525p,480p,625p,576p I can use 4.3, 16.9, JUST, and ZOOM. And all of those seem to include some form of overscan as they fit the black masking perfectly. Its only when you use the 720p or 1080i the settings are fixed without any form of overscan adjustment,hense the nasty edges showing.
     

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