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3:2 Pulldown and 3:2 Pulldown Inversion
Overview
When 24 fps film is converted to 29.97 or 30 Hz HD video, the film frame rate needs
to be up-converted in order to be displayed on a TV set. This process is called 3:2
pulldown.
Basically 3:2 pulldown inversion brings back movie's original frame rate from HD's
29.97 or 30 fps to 24 fps.
3:2 Pulldown
The 3:2 pulldown technique is used to generate video at HD frame rates from a 24
fps film source. With this technique, additional video frames are generated from the
film frames according to a characteristic, repetitive pattern.
An unwanted side-effect of this process is picture redundancy and higher load of an
encoder. The 3:2 pulldown inversion technique inverts the process and removes the
redundant frames thus increasing encoding efficiency.
3:2 Pulldown Inversion
The 3:2 PDI feature of the D9054 HD Encoder excludes the pictures of a 1080i/29.97
Hz video signal that have been duplicated through 3:2 pulldown, and allows the
D9054 HD Encoder to encode the original frames at film rate. The data in the
Transport Stream from the D9054 HD Encoder includes information on picture
repetition so that a standards-compliant decoder may output a video signal at
correct 29.97, 30, 59.94 or 60 Hz HD frame rates.
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D9054 HDTV Encoder Intstallation and Operation Guide
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4038938 Rev A
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