How to digitally un-squeeze after telecine to get a correct 4:3 or 16:9 image

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How to digitally un-squeeze after telecine to get a correct 4:3 or 16:9 image

Using an anamorphot while shooting results in a squeezed 1.33:1 super8-film and hence in a squeezed 4:3 video. This article describes how to get the correct aspect ratio for your video. All calculations will be done for a 1.5x anamorphot and a PAL-video (752(H) x 582(V)). All steps can be done with the free program VirtualDub and its integrated "resize"-filter (Filter mode is set to "precise bilinear", "interlaced" is turned off).
A short remark: the "1.33"-factor is in fact a "4/3"-factor. Hence I've used 4/3 instead of 1.33 in the calculations.

Data-DVDs[edit]

Simply use the "resize"-filter to increase the horizontal width by factor 1.5 (new width: 752*1.5 = 1128; new height: 582). The resulting correctly unsqueezed file can then be played back on any computer and some DVD-players that can handle Data-DVDs with DivX/MPEG2/4/...-files.

Video-DVDs[edit]

Using a videoprojector[edit]

Simply put a 1.5x-anamorphot in front of your projectors lens to unsqueeze the unaltered 4:3 image.
(If you don't have a fitting anamorphot, use the "TV"-methods.)

Using a 4:3 TV[edit]

Use the "resize"-filter to squeeze the image vertically by factor 1.5 and to add black bars:

  • new width: 752
  • new height: 582/1.5 = 388
  • expand frame and letter box image: yes
  • frame width: 752
  • frame height: 582

The resulting video will show correctly on any TV in 4:3 mode.

Using a 16:9 TV and its 1.33x anamorphic desqueezer[edit]

Use the "resize"-filter to squeeze the image vertically by factor 1.5/1.33 and to add black bars:

  • new width: 752
  • new height: 582/1.5*1.33 = 517
  • expand frame and letter box image: yes
  • frame width: 752
  • frame height: 582

The resulting video will show correctly on any 16:9-TV in anamorphic 16:9 mode.

Turning your squeezed standard definition video into an unsqueezed HD video[edit]

Use the "resize"-filter to unsqueeze the image horizontally by factor 1.5/1.33 and to put it into a letterboxed 16:9-image:

  • new width: 752*1.5/1.33 = 846
  • new height: 582
  • expand frame and letter box image: yes
  • frame width: 846
  • frame height: 846/16*9 = 476

The resulting video should show correctly on any 16:9-HDTV in non-anamorphic 16:9 mode. Unfortunately the resulting format is neither 1920 x 1080 nor 1280 x 720. So we'll either need a second "resize"-filter...

  • new width: 1280
  • new height: 720
  • expand frame and letter box image: no

... or we'll have to change the first run a little bit:

  • new width: 1280
  • new height: 720/1.5*1.33 = 640
  • expand frame and letter box image: yes
  • frame width: 1280
  • frame height: 720

Now the resulting video really shows correctly on any 16:9-HDTV in non-anamorphic 16:9 mode.
(Of course having a real HD-transfer would result in a better quality. But at the moment a HD-transfer costs 10 times more than a good SD-transfer.)