What Is 24p Video?
(p. 417)
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Telecine, Pull-Down, and Reverse Telecine
(p. 418)
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Film, 24p Video, and Cinema Tools
(p. 424)
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Working with 24p NTSC Video
(p. 425)
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Using an AG-DVX100 NTSC Camcorder with Advanced Pull-Down
(p. 425)
What Is 24p Video?
The term 24p refers to 24 fps progressive-scan video. For film, this is nothing unusual,
but for video, both progressive scanning and the 24 fps frame rate are still exciting new
territory. Instead of building 24 fps video cameras that would be incompatible with
established NTSC and PAL video equipment, some new camcorders make it possible to
shoot 24p video while maintaining backward compatibility with NTSC or PAL equipment.
Some reasons to shoot 24p footage are:
 To make it easy to transfer your video to film without any frame rate conversions
 To achieve a “film look” on video, even though film was never used
 To use 24p footage as a convenient intermediate format for moving between
NTSC video, PAL video, and film
 To capture at a lower data rate than 25, 29.97, and 59.94 fps formats
∏
Tip: When you shoot video at 24 fps, you need to avoid quick pans and tilts
because they may cause the image to stutter. This is common knowledge for film
cinematographers, but videographers new to 24 fps videography may not always be
aware of this fact.
418
Part V
Appendixes
Telecine, Pull-Down, and Reverse Telecine
The following section describes methods for embedding and extracting 24p video in
different formats. Some of these techniques are based on existing film-to-video
methods, and some are newer approaches. The basic technique for transferring film to
video, called telecine, uses a process called pull-down to map 23.98 fps film to 29.97 fps
interlaced video. Once the video is captured on disk, software can perform reverse
telecine, or reverse pull-down, to restore the original 23.98 fps film frame rate.
In progressive digital video systems such as 720p60 DVCPRO HD video, a similar process
can be performed in-camera to map 23.98 fps to 59.94 fps, but entire frames are
duplicated instead of fields. During or after capture, the duplicate frames are removed.
A camcorder or deck that performs duplicate frame insertion can add metadata (known
as flags) that inform software when to remove or ignore duplicate frames.
Note: Pull-down refers to the addition or removal of fields, not duplicate frames.
Standard 3:2 Pull-Down
Also known as 2:3:2:3 pull-down, this is the standard telecine method of transferring
film to NTSC video. The film is slowed by 0.1 percent (a factor of 1000/1001) from 24 fps
to 23.98 fps and then each film frame is transferred to interlaced video in a repeating
2:3:2:3 field pattern.
In the illustration below, film frames A, B, and D are mapped to video frames 1, 2, and 5.
However, because film frame C is split into two fields across video frames 3 and 4,
pull-down removal requires deinterlacing, which is more processor-intensive than
removal of pull-down patterns such as advanced (2:3:3:2) pull-down. Pull-down
removal typically requires manual identification of the A frame in the pattern, which
you can identify visually by moving frame by frame through your footage until you
recognize the pull-down pattern.