Video standards, Image dimensions and aspect ratio – Apple Final Cut Express HD User Manual
Page 37
Chapter 2
Video Formats and Timecode
37
I
Video Standards
A number of video standards have emerged over the years. Standard definition (SD)
video formats have been used for broadcast television from the 1950s to the present.
These include NTSC, PAL, and SECAM, regional video standards, with each used in
certain countries and regions of the world.
 NTSC (National Television Systems Committee): The television and video standard used
in most of the Americas, Taiwan, Japan, and Korea.
 PAL (Phase Alternating Line): The television and video standard used in most of
Europe, Brazil, Algeria, and China.
 SECAM: A video standard that is based on PAL and used in countries such as France,
Poland, Haiti, and Vietnam. SECAM is not supported by Final Cut Express HD. However,
editing work is usually done in PAL and converted to SECAM for broadcasting.
Important:
When you are specifying your initial settings, make sure you choose an Easy
Setup that corresponds to your country’s video standard. (An Easy Setup is a collection
of settings that determines how Final Cut Express HD works with your editing system.)
For more information, see “
Opening Final Cut Express HD and Choosing Your
Originally, all these formats were analog. Analog video uses a signal that consists of a
constantly varying voltage level, called a waveform, that represents video and audio
information. Analog formats such as VHS must be digitized, or captured, for use by
Final Cut Express HD.
More recently, digital standard definition video formats were introduced, as well as digital
high definition (HD) video formats. Most consumer camcorders today record standard
definition digital video (such as DV) or high definition digital video (such as HDV).
Image Dimensions and Aspect Ratio
The horizontal and vertical pixel dimensions of your format determine the frame size
and aspect ratio. For example, standard definition (SD) NTSC video is 720 pixels wide
and 480 pixels tall. High definition video is either 1280 x 720 or 1920 x 1080, and is
usually referred to by the vertical dimension and the frame rate (for example 720p60 or
1080i30).
The aspect ratio of a video frame is the width with respect to the height. Standard
definition video has an aspect ratio of 4:3, while high definition uses 16:9.
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 standard definition digital video uses pixels that
are rectangular, not square. For more information, see Appendix A, “