Memory Storage Calculations
Show your work for each problem.
(a) Your PC has a 24-inch widescreen flat panel monitor, whose resolution is 1920 × 1200 pixels. If you
are currently using 32 bits of color information per pixel, how much storage would be required to make
a “screen shot” of your PC screen, without compression? Express your answer in binary-style MB.
(b) The reptile pet owners association is considering adding a video clip posting capability to its website. A
member survey suggests that the number of clips that would be posted on the site would be about
30,000. Assume each clip is 300 × 400 pixels resolution, with 24 bits per pixel and 30 frames per
second, and that clips average 3 minutes long. Disregarding the audio component of each clip, and
assuming you store the clips in a compressed format with an average compression factor of 40, how
much storage will be needed for the video clip library? Express your result in binary-style GB.
(c) You use a digital voice recorder to record confusing college lectures. The recorder uses CD-quality
sound, that is, 44,100 samples per second with 16 bits per sample, but only records one channel. You
have found that you can record 7 lectures, each 80 minutes long, before the 256-MB (binary style)
memory card in the recorder fills up. What compression factor is the software on the recorder
achieving when it stores the audio information?
Memory Storage Calculations – Solution
a)
2
bits bits bytes
1920 1200 pixels 32 8 9,216,00 bytes 1024 = 8.79 MB
pixel byte MB
b) We calculate:
300
horizontal pixels
×
400
vertical pixels
×
3
bytes/pixel = 24 bits/pixel
×
3
minutes
bytes
2MB
Original size 2,963,520,000 bytes
Compression factor 11.0
Compressed size 256 MB 1024
.
×
seconds/minute
frames/second
×
clips
=
bytes
compression factor
=
bytes
B/GB
=
1358
GB (= 1.33 TB)