Apple Final Cut Pro HD (4.5): New Features - Manual (Page 110)

110 Appendix High Definition Video Fundamentals
Discussing HD Formats in Conversation
Because there are so many possible HD formats, it’s best to be as specific as possible
when describing a particular variant. Always mention the image dimensions, frame
rate, and scanning method.
Often, people in the film and video industries abbreviate HD format names to either the
frame rate or image dimensions (but not both) with the scanning method tagged on to
the end (for example, 24p or 1080i). The letter i indicates an interlaced scanning method,
and the letter p indicates progressive scan. Sometimes, formats are abbreviated because
they are being discussed categorically instead of specifically. 24p is commonly discussed
as video at the film frame rate, but does not go into details such as the image dimensions
or the actual frame rate, which could be either 24 fps or 23.976 fps.
Eventually, you’ll memorize the various frame rates and image dimensions of the
common HD formats, as well as better understand the contexts in which they are
discussed. Meanwhile, the examples below may help you get started distinguishing HD
formats discussed in the film and video industries.
Determining Frame Rate From Image Dimensions
The following example suggests ways of assessing the frame rate of an HD video
format when only an image dimension is used in the name.
1080i refers to a frame size of 1920 x 1080, and the i indicates that the frames are
interlaced. But what is the frame rate?
Since the frame rate isn’t specifically expressed in the name 1080i, you can usually
determine the frame rate based on the particular brand of HD format or the context in
which the format is being used.
1920 x 1080 DVCPRO HD can only be recorded at 29.97, 30, or 25 fps, so the country and
specific camera used can most likely determine which frame rate is implied (29.97 fps
for NTSC, 25 fps for PAL).
If the context of the conversation involves shooting film, it’s likely that the frame rate
for a 1920 x 1080 image is 23.98 or 24 fps (and consequently the format would not be
DVCPRO HD, since 24 fps is not currently supported at 1920 x 1080 using this format).
UP01022.Book Page 110 Tuesday, March 23, 2004 7:32 PM