Apple Final Cut Pro 7 - Manual (Page 1897)

Aspect Ratio of the Video Frame
The ratio of horizontal to vertical dimensions of a film or video frame is called the aspect
ratio. Aspect ratio is independent of absolute image size or resolution.
Widescreen cinema
2.40:1
Standard cinema
1.85:1
High definition
1.78:1
(16 x 9)
Standard
definition
1.33:1
(4 x 3)
Aspect ratios can be expressed as absolute dimensions (4 x 3), a ratio (4:3), a fraction (4/3),
or as the decimal equivalent of a ratio (1.33:1, or simply 1.33). Aspect ratios are generally
expressed according to the following conventions:
• Video aspect ratios are often written as ratios, such as 4:3 for SD video or 16:9 for HD
video.
• Film aspect ratios are often written as decimal equivalents, such as 1.33, 1.85, and 2.40.
The larger the decimal number, the wider the image. An aspect ratio of 2.40 is wider
than 1.85, and 1.85 is wider than 1.33.
• Digital video resolutions are usually written as absolute pixel dimensions, such as
720 x 480, 1280 x 720, 1920 x 1080, and so on.
Below is a list of commonly used aspect ratios, mostly from the film and television industry,
plus a few others for comparison.
Medium Aspect ratio
Early 35 mm film and SD television 1.33 (4:3)
4-perforation 35 mm camera footage (prior to projection)—also
known as “Academy” aspect ratio 1.37
Standard European film; masked in projector 1.66 (15:9)
HD television 1.78 (16:9)
Standard North American and UK film; masked in projector 1.85
1897 Appendix B Video Formats