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Posted by Steve Roberts on 04/29/07 18:43
On Sun, 29 Apr 2007 17:09:54 GMT, Kate <lorisoard@sbcglobal.net>
wrote:
>The PAL to NTSC conversion recipe uses three freeware programs
>i. DGIndex
>ii. TMPGEnc
>iii. DGPulldown
>
>Corresponding, I think, to the three general PAL-to-NTSC conversion steps
>a. Separate the PAL movie into d2v video and ac3 audio channels
>b. Combine them back into a PAL/NTSC hybrid with NTSC frame size (720x480)
>and PAL frames per second (25 fps)
>c. Convert the PAL/NTSC hybrid frames per second to NTSC
>
>Do I have the gist of the necessary PAL to NTSC conversion steps correct?
Yes, but be warned that the results may be very poor, depending on
whether the orignal PAL material is frame-based (ie film) or
field-based (ie video-originated material like a sitcom or live
event).
Basically what you are doing in these steps is treating the PAL
material as though it was film running at 23.98fps. You're effectively
slowing the PAL material down about 4% from 25fps to 23.98fps,
resizing the frames to NTSC standard and then adding 3:2 pulldown
field repeats to convert to standard NTSC video at 59.94 fields per
second.
Two points here: Firstly the programme will now run slightly slower
and longer than it should. Secondly, depending on the source material
type and the method used to resize the frames, you may run into some
hideous motion artefacts. Step B is the critical one here - if the
material is video-originated, you're going to want to do some kind of
de-interlacing here before you resize the frames.
Steve
The Doctor Who Restoration Team Website
http://www.restoration-team.co.uk
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