Fluency with Information Technology, 6e (Snyder)
Chapter 8 Representing Multimedia Digitally: Light, Sound, Magic
8.1 True/False Questions
1) Each pixel on a computer display is formed from three colored lights: red, yellow, and blue.
2) RGB, the name for a color encoding method, is an acronym for red, green, blue.
3) All colors with equal intensities of the RGB subpixels are always some shade of gray.
4) Contrast is the size of the difference between the darkest and lightest pixels.
5) To represent the color of a single pixel requires three bytes.
6) Active Matrix displays are the standard “flat” or “thin” displays used for laptops, phones, and
most familiar video applications.
7) An object creates sound by vibrating in a medium. The force, or intensity of the push,
determines the pitch, and the frequency (the number of waves per second) of the pushes is the
volume.
8) Digitizing a sound wave requires that the analog wave be converted to bits.
9) When digitizing sound, a slower sampling rate does not affect the recorded wave since there
are some frequencies that the human ear can’t hear.
10) To play a digitized sound, the numbers are read from memory into a digital-to-analog
converter (DAC), which creates an electrical wave that is then input to a speaker.
11) MP3 is popular for Internet transmission because it yields higher quality even though this
also requires higher bandwidth requirements.
12) Run-length encoding is a lossy compression scheme.
13) As the amount of compression is increased in JPEG, eventually the picture begins to
“pixelate,” or as slang goes, it gets “jaggies.”
14) MPEG and other compression schemes only need moderate amounts of bandwidth, allowing
us to watch videos on YouTube and Hulu.
15) Making Yellow using paint and making Yellow on a computer screen are very similar
processes.
16) Higher bandwidth usually means higher latency.
17) The Bias-Free Universal Medium Principle means that bits have no inherent meaning, but
can represent any discrete information.
18) Because of its inaccuracy, lossy compression is useless for multimedia files.
1) Using a scanned black and white photo, suppose the subpixels of one pixel had values of 195.
If the image’s pixels should all be nearer intense white keeping their relative relationships, the
subpixels of the given pixel could be changed to values of:
A) 179, 179, 179
B) 212, 212, 212
C) 0, 0, 0
D) Both A and C would be suitable.
2) A digitization guideline stating that the sampling frequency should exceed the signal
frequency by at least two times is the:
A) Analog-Digital rule
B) Leibniz rule
C) Nyquist rule
D) Sample Rate rule
3) The decimal number 174 is equivalent to the binary number:
A) 1010 1110
B) 1110 1111
C) 1101 1010
D) 0001 1101 1100
4) Digitized sound can be:
A) “fixed” by removing offending noises
B) processed to reduce the number bits
C) reproduced exactly
D) all of the above
5) Digitizing sound:
A) requires lossless compression techniques
B) achieves perfection using an unlimited number of bits
C) uses bits to represent both positive and negative values
D) is compressed using MPEG
6) GIF encoding:
A) is a lossless encoding scheme
B) can display 1024 different colors
C) is used for photographs
D) was invented by the Joint Photographic Experts Group of the ISO
7) Which statement is incorrect?
A) OCR is very sophisticated technology.
B) OCR’s business applications include sorting mail and banking.
C) OCR systems can easily interpret words created by reCaptcha.
D) OCR can be used to read the handwritten digits on checks.
8) The meaning of bits depends upon:
A) their inherent meaning
B) the principles applied by the transmission medium
C) the interpretation placed on them by computer programs
D) the ability to perform analog-to-digital conversion
9) Adding a positive number to each component of each pixel in an image will
A) brighten the image
B) turn the image black
C) darken the image
D) improve the contrast of the image
10) The quality of a sound recording is determined by the _________ and the sample precision
A) sample rate
B) bit width
C) sample speed
D) notification rate
1) ________ refers to how close to white the pixels are.
2) ________ are small points of colored light arranged in a grid to form a computer display.
3) ________ is the brightness of the light of a subpixel of an LCD display, typically ranging from
0 to 255.
4) ________ results from turning on all three lights (subpixels) at high intensity.
5) To ________ means to take measurements at regular intervals, as in sound digitization.
6) ________ is the factor by which compression reduces an encoding from its uncompressed
size.
7) ________ compression is the process of reducing the number of bits required to represent
information in which the original form can be exactly reconstructed.
8) ________ compression is the process of reducing the number of bits required to represent
information in which the original cannot be exactly reconstructed.
9) ________, the compression scheme of the Motion Picture Experts Group of the ISO, is
applied to motion pictures.
11) ________ is a measure of how much information is transmitted per unit time.
12) ________ is the time required to deliver or generate information.
13) The Nyquist rule requires that, to capture frequencies up to 17,000 Hz, you must sample at a
rate of at least ___________ Hz.