3. A multimedia version of a multivolume reference book is being prepared for storage on a compact disk (CD). Each disk can store about 600MB. The input to each volume consists of 1000 pages of text typed 10 characters to the inch, six lines to the inch, on a 8-by-11-in. paper with 1-in. margins. Each volume also has about 100 pictures, which will be displayed in color at Super VGA resolution (1024 x 768 pixels, 8 bits/pixel). Moreover, each volume is enhanced for the CD version with 30 min of audio of teleconferencing quality (16,000 smp/sec, 6 bits/smp).
a.
How
many bits are there on a 600-MB CD?
600 x 1,048,576 = 5,033,164,800 bits = 5Gb
b.
Without
compression and ignoring overhead, how many volumes can be put on one
CD?
Data: 1000 pages x (9x6) lines x (6.5x10) x 8
bits/char = 28.1 Mb
Images: 100 x (1024x768x8) = 629.1 Mbits
Audio: 30min x 60sec/min x 16,000 samples/sec x
6bits/sample = 172,800,000 = 172.8 Mbits
Total is 830Mb = 5000/830 =~ 6 volumes per CD
c.
Suppose
that the material is to be transmitted over a T-1 facility (1.544 Mbps). How
long will it take, exclusive of overhead, to
transmit a volume?
830Mb/1.544 Mbps = 537.6 seconds = 9 mins
d.
Suppose
that the text can be compressed at a 3:1 rate, the picture at 10:1, and the
audio at 2:1. How many volumes, exclusive of
overhead, will fit on a CD? How
long will it take to transmit compressed volume on a T-1 channel?
Date: 28.1/3 = 9.4 Mb
Image: 629.1/10 = 62.9 Mb
Audio: 172.8/2 = 86.4 Mb
Total: 158.7 Mb or about 32 volumes on a CD
Transmission time: 158.7/1.544 = 103 seconds = 1min,
43 seconds