Apple Final Cut Pro HD (4.5): New Features - Manual (Page 111)

Appendix High Definition Video Fundamentals 111
Determining Image Dimensions From Frame Rate
The following example suggests ways of assessing the image dimensions of an HD
video format when only the frame rate is given in the name.
24p describes an image recorded progressively at either 23.98 or 24 fps. But what are
the image dimensions?
If you are using DVCPRO HD, only frame sizes of 1280 x 720 support 23.98 and 24 fps
recording. Some standard definition DV and DVCPRO 50 cameras can also record
progressive frames at 23.98 fps, using image dimensions of 720 x 480.
Other HD cameras can record 23.98 or 24 fps with image dimensions of 1920 x 1080,
but these cameras often use 24psF (progressive frames segmented stored in an
interlaced signal structure). See “
24psF ” on page 108 for a description of this format.
Upconverting and Downconverting
To fully experience the quality of HD video, a complete HD system is necessary: HD
camcorders, tape formats, editing systems, broadcasting services, and finally, HD
televisions and receivers. Because HD systems are still relatively new, many video
producers find that they need to combine HD with SD footage, or several HD sizes,
within the same project.
Converting a video format to a higher resolution format is called upconverting and the
reverse is called downconverting. However, the process of upconverting and
downconverting is not as simple as scaling a video frame. Changes in aspect ratio,
mostly between 4 x 3 (standard definition) and 16 x 9 (high definition) are also part of
the process.
Some reasons you may need to convert between HD and SD or vice versa are:
• If you are working on an HD project using archival footage (which is still mostly
standard definition)
• If you have finished editing an HD program and you need a distribution copy in a
standard definition format like Digital Betacam, DV, DVD, or VHS
• If you are combining high definition footage such as a feature film transfer into an
SD project
The most common scenarios are upconverting SD footage for use in an HD sequence
and downconverting HD projects to SD distribution formats, which clearly
demonstrates that HD is becoming a prevalent mastering format.
UP01022.Book Page 111 Tuesday, March 23, 2004 7:32 PM