PAL -> NTSC conversion : the digital way

NTSC and PAL video standards differ in both framerate and resolution. Hardware equipment that will do the conversion exist, but is expensive. With a computer, there is a method for converting a PAL video file to NTSC in a near-perfect way:

Changing frame size
Raising framerate
Adjusting field order (optional)
Adjusting audio duration

This process is simpler when the source clip is progressive, because usually, PAL and NTSC equipment use a different video field dominance. This means that one presents the lower/bottom/odd field first (normally NTSC), while the other puts the upper/top/even field first (normally PAL). However, you should realize that interlacing is specific to high-resolution video originating from PAL or NTSC video cameras. Low-resolution material like VideoCDs, as well as FILM sources (which are progressive), are not subject to this problem. The main drawback of doing PAL-to-NTSC conversion is the small loss of fluidity introduced when fields/frames are duplicated to raise the framerate of the source clip.

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