Scan Lines and Resolution?

Discussion in 'Displays' started by Mike Wladyka, Oct 8, 2003.

  1. Mike Wladyka

    Mike Wladyka Supporting Actor

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    Can someone explain to me how these relate to each other? How does a projector with resolution of 800x600 project a 720p signal? Does each scan line get 1.11 pixels? Is that even possible? How?
     
  2. David Abrams

    David Abrams Stunt Coordinator

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    Mike,

    Scan lines and resolution do correspond to one another; however, they can be very confusing. The projector or display is most likely accepting the 720p signal, but then downconverting it to fit the native resolution of the display. With DVDs it would need to upconvert them to fit the native resolution of the display.

    So in short, the projector is not capable of resolving a true 720p signal which is 1280x720.

    Regards,
     
  3. Mike Wladyka

    Mike Wladyka Supporting Actor

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    so the only way to get 720p is to have 1280x720, what if you have more resolution, say sending a 540p signal to 1280x720 resolution?...or is the only way to get a true signal is to have 1 scan line per 1 row of pixels?
     
  4. David Abrams

    David Abrams Stunt Coordinator

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    Mike,

    If you have a display with a native resolution, meaning the panel or chip is that particular resolution, then that display will show everything at that rate. This does not mean that everything is in that resolution. What I mean by this is that if you have a DVD that has a pixel count of 720x486, then that is the most resolution you can get out of that DVD.

    Now you can upconvert and scale the image to a higher scan rate, but this will not create detail. You cannot creat detail that isn't already there. This is why upconverted non-HD material doens't look anywhere near as good as native HD material. While you can upconvert the image and make it appear sharper and cleaner, it does not add more resolution to that image.

    Resolution numbers are very tricky. We, as an industry, have not been able to set a definable standard quite yet that everyone agrees on. This can cause a significant amount of confusion among consumers.

    You mention 540p having a higher resolution than 720p (1280x720). If the 540p signal is true 1920x540p then yes the pixel count would be higher than 720p; however, there are extremely few sources of material at this time that have full 1920x540 or 1920x1080p resolution. The reason for this is the incapability to go all the way out to 1920. We now have ways of doing this, but they are not being utilized very much.

    Most HDTV sources are 1080i via SonyHDCam which is a 1440x1080i format. I believe the format is in the process though of going to a higher resolution.

    Basically, if your display handles 800x600 as its' native rate then everything will be shown at that rate, or possibly squeezed with some mode actually showing less resolution. If the source doesn't have that resolution or has more resolution then it may still be able to be shown on that display but it will be upcoverted or downconverted to accomodate.

    Regards,
     
  5. Mike Wladyka

    Mike Wladyka Supporting Actor

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    Thanks David for the explanation, i think i have a handle on it now
     

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