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Old 12th December 2004, 15:54   #64  |  Link
Wilbert
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Join Date: Nov 2001
Location: Netherlands
Posts: 6,364
@scharfis_brain

Quote:
Natural video is not that suited for checking for half pel chroma displacements, I think.
So I came to that (probably wrong) conclusion that DV Cams are building conventional YV12.
I disagree. But, perhaps it differs by DV codec. Let's consider MainConcept, and look at the following script

Code:
function translation(clip clip, clip "LClip", int "start_frame", int "beginX", int "beginY", int "end_frame", 
  \  int "endX", int "endY") {
  return Animate(start_frame, end_frame, "layer", clip, LClip, "Add", 255, beginX, beginY, 
    \  clip, LClip, "Add", 255, endX, endY)
}


c = BlankClip(width=720,height=576,pixel_type="YUY2")
c2 = ImageSource("F:\411_vs_420\1-720-pal.bmp",0,250,25,false).ConvertToYUY2()

ct = translation(c, c2, 0, 0, 0, 99, 720, 288)
cf = ct.SeparateFields.SelectEven
cf.Weave
AssumeFPS(25)
c1 = last.KillAudio

c2 = DirectShowSource("F:\411_vs_420\mc_int.avi", fps=25)  # interlaced YV12
#ConvertToYUY2(interlaced=true)
c1 = c1.ConvertToYV12(interlaced=true)

#Subtract(c1,c2)
StackVertical(c1,c2)
1) picture: http://www.geocities.com/wilbertdijkhof/pal.zip
2) mc_int.avi is the script (forming the clip "c1") encoded with MainConcept (also in pal.zip).

If mc_int.avi would have been upsampled to YV12 using MPEG-2 sampling, the clips c1 and c2 would be identical. As you can see, they are not.
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