Apple Final Cut Pro 7 - Manual (Page 38)

More recently, digital SD video formats were introduced, as well as digital high definition
(HD) video formats. Most consumer camcorders today record SD digital video (such as
DV), and professional cameras may record SD, HD, or digital cinema video.
Image Dimensions and Aspect Ratio
The horizontal and vertical pixel dimensions of your format determine the frame size and
aspect ratio. For example, SD NTSC video is 720 pixels wide and 486 pixels tall. HD video
is either 1280 x 720 or 1920 x 1080, and is usually referred to by the vertical dimension
(for example, 720 or 1080) and the frame rate. In addition, Final Cut Pro refers to interlaced
HD formats according to their field rate rather than frame rate; for example, 1080i60
(59.94 fields per second) rather than 1080i30 (29.97 frames per second). Digital cinema
formats are generally referred to using their horizontal dimension as either 2K, 3K, or 4K,
shorthand for at least 2,000 pixels, 3,000 pixels, or 4,000 pixels wide.
The aspect ratio of a video frame is the width with respect to the height. SD video has
an aspect ratio of 4:3, while HD video uses 16:9. Digital cinema formats use the 16:9 aspect
ratio as well as closely related film-based aspect ratios.
Note: You may notice that 1280/720 or 1920/1080 is equivalent to 16:9, while 720/480
is not equivalent to 4:3. This is because SD digital video uses pixels that are rectangular,
not square. For more information, see
“Video Formats.”
Frame Rate
The frame rate of your video determines how quickly frames are recorded and played
back. The higher the number of frames per second (fps), the less noticeably the image
flickers on screen. There are several common frame rates in use:
• 24 fps: Film, certain HD formats, and certain SD formats use this frame rate. This may
also be 23.98 fps for compatibility with NTSC video.
• 25 fps: SD PAL, HD PAL
• 29.97 fps: SD NTSC, HD NTSC (720p30, 1080p30, and 1080i60)
• 50 fps: 720p HD
• 59.94 fps: 720p HD
• 60 fps: 720p HD
For more information, see “Frame Rate and Timecode.”
Scanning Method
Video frames are composed of individual lines, scanned from the top of the screen to the
bottom. Lines may be scanned progressively (one line at a time), or interlaced (every
other line during one scan, and then the alternate lines on a subsequent scan). For more
information, see
“Video Formats.”
38 Chapter 2 Video Formats and Timecode