Apple Final Cut Pro HD (4.5): New Features - Manual (Page 108)

108 Appendix High Definition Video Fundamentals
High Definition Versus Standard Definition Video Formats
Whenever a new format is introduced, it needs to be distinguished from the formats
that already exist. Standard definition video wasn’t a commonly used term until the
latest high definition formats were introduced a few years ago.
High definition has two slightly different meanings. Generally speaking, the term high
definition describes any image or sound format that is higher resolution than another
format. Today, high definition (HD) also specifically refers to high definition video
formats such as HDCAM, DVCPRO HD, HDV, and the current ATSC HDTV specifications.
High Definition Formats in Common Use
Every major video manufacturer is developing high definition technology. As a result,
many different formats are available to choose from.
24P Video
Formats that capture complete (progressive) video frames at 24 frame per second have
received a lot of attention lately. This is because 24p video specifications are similar to film
standards. A 24 fps,1920 x 1080, progressively scanned video format closely matches
35mm film theater distribution prints. For the first time since the invention of television,
moviemakers can choose video instead of film without sacrificing significant resolution
loss or having to cope with frame rate conversions. Now that the technology is available,
which medium to use has become more of an aesthetic and budgetary choice.
Scanning Methods
Most high definition formats can record both progressive and interlaced video.
• Interlaced scanning: Odd lines are first drawn onscreen (called field 1), followed by
the even lines (field 2) to complete a single frame.
• Progressive scanning: Every line is scanned until a complete frame is drawn. There are
no fields.
24psF
Some HD equipment uses a third method to store progressively captured camera
images within an interlaced structure on tape. This format is called progressive
segmented frame (psF), and it is usually discussed in reference to 24p video.
This method cleverly adapts existing1080i50 video (1080 interlaced lines running at 50
fields per second) to 1080i48, using both fields to store a single progressive frame.
While this could be called1080p24, it’s technically 1080psF because each progressive
frame is stored on tape as two interlaced fields that were actually captured from the
camera CCD at the same time.
UP01022.Book Page 108 Tuesday, March 23, 2004 7:32 PM