Basic Betacam Camerawork, 3rd Edition

Compression standards

4:2:2

A common sampling rate for 625/50 and 525/60 video is chosen to be locked to the horizontal sync pulses. For the luminance signal this is often 13.5 MHz. Only the active lines (576 lines in the 625 system) are transmitted or recorded. Each line consists of 720 pixels. The 49 field blanking lines are ignored and recreated when required.

In the Betacam recording format (see Betacam format, page 30) the colour difference signals have one half the luminance bandwidth and are sampled at half the luminance sample rate of 13.5 MHz (i.e. 6.75 MHz). The lowest practicable sampling rate is 3.375 MHz – a quarter of the luminance rate and identified as 1. Using this code convention:

1 = 3.375 MHz sample rate (3,375,000 samples ...