Using the ITU-R 601 4:2:2 digital coding standard, each picture occupies a large amount of storage space, especially when related to computer storage devices such as DRAM and disks. So much so that the numbers can become confusing unless a few benchmark statistics are remembered. Fortunately, the units of mega, giga, tera and penta make it easy to express the very large numbers involved. The capacities can all be worked out directly from the 601 standard. Bearing in mind that sync words and blanking can be regenerated and added at the output, only the active picture area need be stored. For the 525 line TV standard the line data is: 720(Y) + 360(Cr) + 360(Cb) = 1,440 pixels/line 487 active lines/picture there are 1,440 x 487 = 701,280 pixels/picture (sampling at 8-bits, a picture takes 701.3 kbytes) 1 sec takes 701.3 x 30 = 21,039 kbytes, or 21 Mbytes For the 625 line TV standard the active picture is: 720(Y) + 360(Cr) + 360(Cb) = 1,440 pixels/line With 576 active lines/picture there are 1,440 x 576 = 829,440 pixels/picture (sampling at 8-bits, a picture takes 830 kbytes) 1 second takes 830 x 25 = 20,750 kbytes, or 21 Mbytes So both 525 and 625 line systems require approximately the same amount of storage for a given time: 1 minute takes 21 x 60 = 1,260 Mbytes, or 1.26 Gbytes 1 hour takes 1.26 x 60 = 76 Gbytes Useful numbers (referred to non-compressed video): 1 Gbyte will hold 47 seconds. 1 hour takes 76 Gbytes.