Apple Final Cut Express HD - Manual (Page 1037)

Appendix A Video Formats 1037
XIII
In Final Cut Express HD, there are two options for field dominance:
 Upper (field 2 is dominant, so the second field is drawn first)
 Lower (field 1 is dominant, so the first field is drawn first)
Generally, Upper is used by 640 x 480 systems, while Lower is most common in
professional 720 x 486 and DV 720 x 480 systems.
Color Recording Method
The color recording method of a video format may be either RGB, component (Y´C
B
C
R
), S-
Video (Y/C), or composite. The more discrete channels a format has, the higher the
quality of the image, but the more data required to store and transmit that information.
Today, almost all digital video formats are component Y´C
B
C
R
. Computers typically store
image data using RGB, although many component (Y´C
B
C
R
) formats can now be
processed natively on the computer (such as DV).
Video Sampling Rate and Color Sampling Ratio
The video sampling rate of a digital video format determines how often the light
intensity of each video line is sampled.
Color recording method Video formats
Composite 1”, 3/4” U-matic, 1/2”, VHS, D-2, D-3.
S-Video (Y/C) Hi8, S-VHS.
Component (Y´C
B
C
R
) BetacamSP, Digital Betacam, DVD, DV, D-1, D-5.
RGB Computer video and graphics files; this format is rare for tape
formats. HDCAM SR can be used to record RGB video.
Sampling Rate Description
74.25 MHz High definition video luma (Y´) sample rate.
37.125 MHz High definition video chroma (C
B
C
R
) sample rate. This is half of the
luma sample rate, used for 4:2:2 high definition video.
14.3 MHz Early NTSC digital video recorders sampled video at exactly four
times the frequency of the color subcarrier signal (3.58 MHz x 4).
This is the origin of the 4 in color sampling ratios such as 4:2:2.
13.5 MHz This is the sampling rate for the luma (Y) channel for standard
definition digital video. This sampling rate was chosen to work with
both NTSC and PAL digital video. The 4 in the 4:2:2 is now
represented by this sampling rate.
6.75 MHz This is the sampling rate for the color difference channels in 4:2:2
video. This is half of 13.5 MHz.