1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Line doubling, tripling, quadrupling on CRT

Discussion in 'Projectors, Screens & Video Processors' started by cosaw, Jul 20, 2003.

  1. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    This is a theoretical querry as I don't have a CRTpj yet!

    Potnetial setup: HTPC to Barco 801 or similar with PAL dvds 7-8ft screen.

    I understand that Line doubled video is effectively progressive output. Thereafter tripling/quadrupling is actually adding extra lines of image by scaling/interpolating. Am I right? However I've also read that the res I wan't to run at would be 800x600 for 16:9. Anything higher and the lines of the picture start to overlap and the picture becomes soft. So if I ran at 576p that would be fine.

    So what then would be the point of tripling/quadrupling if it spoils the image? Is line tripling/quadrupling for when you have a much bigger screen furhter away and scan lines would start to become visible? I can't visualise this as surely the point at which lines overlap is an inherent characteristic of the particular projectors theoretical resolution and how small a dot it can draw not how far away the screen is?

    I'll have to post on HTPC to find out how to go about tripling/quadrupling via PC as well! :lesson:
     
  2. Gordon @ Convergent AV

    Gordon @ Convergent AV
    Distinguished Member AVForums Sponsor

    Joined:
    Jul 13, 2000
    Messages:
    13,979
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Living in Surrey, covering UK!
    Ratings:
    +2,780
    You are correct that in your scenario the physical set up of the PJ will determine the optimum lines you want to draw on face of tube before overlap and softening starts happening.

    Tripling and Qudrupling are most probably remnants of older days when scaling technology was a lot less clever. Tripling NTSC now of course comes up with the correct vertical resolution for 720P fixed pixel products but that is another forum.

    576P should be pretty nice on something like an 801/12XX unit

    Gordon
     
  3. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Thanks for clarifying that Gordon, it's nice to get these things straight in your head when your new to the subject as myself.

    By the way any new news of progress on the "How to CRT" article on your website?
     
  4. Gordon @ Convergent AV

    Gordon @ Convergent AV
    Distinguished Member AVForums Sponsor

    Joined:
    Jul 13, 2000
    Messages:
    13,979
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Living in Surrey, covering UK!
    Ratings:
    +2,780
    How to CRT will not be updated for quite some time sorry. Other interesting developments at Convergent continue to get in the way. If/when I build my own demo facility I might continue it.

    Gordon
     
  5. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Fair enough, only so many hours in the day and all that!

    cosaw
     

Share This Page

Loading...