Apple Final Cut Pro HD (4.5): New Features - Manual (Page 118)

118 Appendix High Definition Video Fundamentals
The reason DVCPRO HD internally uses rectangular pixels is to reduce the overall
amount of data recorded to tape and disk, but you shouldn’t need to worry about
these behind-the-scenes format details while you shoot or edit. An HD SDI signal
output from an HD VTR or camera has square pixels, a welcome relief for video graphics
designers after struggling to understand standard definition rectangular pixels.
Note: Standard definition digital formats were originally designed to create a single
digital format capable of sampling both NTSC and PAL 720 times per line. To fit both
576 lines (PAL) and 480 or so lines (NTSC) while using a consistent number of samples
(720) per line, rectangular pixels (or pixels that represent rectangular portions of the
screen) must be used. ITU-R 601 (formerly referred to as CCIR 601), was first
implemented in the D-1 tape format in 1986. All component digital SD formats have
since adopted this approach, including DV, DVCAM, DVCPRO, D-5, Digital Betacam,
Digital S (D-9), DVD, and so on. Unlike the DVCPRO HD pixels which actually subsample
and reduce the amount of overall data, SD video records and shows all the pixels.
Color Depth and Video Sampling Rate
DVCPRO HD records component Y'C
B
C
R
color, sampling at a component ratio of 4:2:2.
Each sample (pixel) is recorded natively at 8-bit. FireWire transfers color natively at 8-bit
color depth, and HD SDI transfers each color sample as a10-bit value.
Frame Rate
DVCPRO HD is capable of recording and playing back all the ATSC specified frame rates
as well as a PAL-compatible frame rate. In practice, the NTSC-related frame rates are
used far more often than the integer rates.
• Integer frame rates: 60, 30, and 24 fps
• NTSC-related frame rates: 59.94, 29.97, and 23.98 fps
• PAL-related frame rate: 25 fps
Note: 25 fps 1080i video cannot be adjusted to an NTSC-related frame rate.
UP01022.Book Page 118 Tuesday, March 23, 2004 7:32 PM