Cropping & Resizing ??

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  • Metamorphous
    Junior Member
    Junior Member
    • Nov 2003
    • 2

    Cropping & Resizing ??

    My question is somewhat elementary but after having encoded a few films this just occurred to me.

    Assuming that I crop an anemographic 1.85:1 film that I have ( pre-resizing its going to be 720x576 ) 12 pixels from top and 12 pixels from the bottom thus making new res: 720x552. Now I have noticed that on most guides it says that the next step would be just to resize it to intended res that being in this case: 720x392 HOWEVER should the deduction of black bits not be taken into account here to and also be substituted on this scale to keep proportions?

    I guess what I am saying is shouldn’t the actual new size be something like (just dealing with height):
    392 - ((392/576)*24) = ~ 376

    I think excluding the black bits would equate to 720x376 as the closest match/ proportion to what was intended. Further more DVD players do not look for/ crop black bits they just resize content as is and with 576 if you resize to 392 then crop the black bits you would see that it would equate to about 8 from top and 8 from bottom:

    ((392/576)*24) = 16.333...

    I tried this in VirtualDub and confirm it to be so. So am I correct in thinking what I am about keeping proportions using this method ?
  • Enchanter
    Old member
    • Feb 2002
    • 5417

    #2
    That's one hell of a confusing read.

    Without getting too obsessed on numbers (as you apparently are), I would suggest to you that the whole point on cropping & resizing is about removing unwanted black parts and resizing (reshape, if you prefer the word) the picture so that everything looks proportionate, respectively.

    Your eyes are the best judge for that. Not numbers.

    Regards.


    Edit:
    When resizing, it is easiest to base your numbers on the aspect ratio of the particular video. As far as I know, we have 4:3 (TV), 16:9 and 2.35 for aspect ratios.

    This simple theory will work out far better.
    Last edited by Enchanter; 4 Nov 2003, 12:28 AM.

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    • SpikeSpiegel
      Gold Member
      Gold Member
      • Apr 2003
      • 141

      #3
      Hi!

      There are many methods to find proportions and....congratulation, you have found the hardest one!

      You could use a program like DVX or even Flask, but I see you like the "hard way", and, for you're not the only one, I'll teach you my method

      The declared "format" could not be the real one, so: open one vob file (maybe not the first, neither the last) with DVD2AVI Gloval and press F5 (preview), on the 1st line of the window that appears you can see the real format (16:9 or 4:3)
      In "Video/Clip & Resize/Clip&ResizeOgo", moving TOP and BOTTOM sliders you can find the height of the "black bars" that you must remove (be sure to leave all other options as default)
      If format is 16:9 the final height (cropping black bars) will be (576-TOP-BOTTOM)*0.703, if it's 4:3 -> (576-TOP-BOTTOM)*0.9375
      Fast and easy (I'm sure somebody will quote this adding some insults ).

      P.S.
      The reason:
      720*(9/16)=405, 405/576=0.703
      720*(3/4)=540, 540/576=0.9375

      Comment

      • Rommyke
        Junior Member
        Junior Member
        • Dec 2003
        • 34

        #4
        woooooouw

        that was also just the thing I was looking for but It is a littke bit too confusing , so if that is the way to do it , I think I keep it like it is

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