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Data Storage – Part 2
CS 1 Introduction to Computers and Computer
Technology
Rick Graziani
Fall 2010
Digitizing Text
• Earliest uses of PandA (Presence and Absence) was to digitize text
(keyboard characters).
• We will look at digitizing images and video later.
• Assigning Symbols in United States:
– 26 upper case letters
– 26 lower case letters
– 10 numerals
– 20 punctuation characters
– 10 typical arithmetic characters
– 3 non-printable characters (enter, tab, backspace)
– 95 symbols needed
Rick Graziani graziani@cabrillo.edu 2
ASCII-7
• In the early days, a 7 bit
code was used, with 128
combinations of 0’s and 1’s,
enough for a typical
keyboard.
• The standard was developed
by ASCII (American
Standard Code for
Information Interchange)
• Each group of 7 bits was
mapped to a single keyboard
character.
0 = 0000000
1 = 0000001
2 = 0000010
3 = 0000011
… 127 = 1111111
Rick Graziani graziani@cabrillo.edu 3
Byte
Byte = A collection of bits (usually 7 or 8 bits) which
represents a character, a number, or other information.
• More common: 8 bits = 1 byte
• Abbreviation: B
Rick Graziani graziani@cabrillo.edu 4
Bytes
1 byte (B)
Kilobyte (KB) = 1,024 bytes (210)
• “one thousand bytes”
1,024 = 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2
Megabyte (MB) = 1,048,576 bytes (220)
• “one million bytes”
Gigabyte (GB) = 1,073,741,824 bytes (230)
• “one billion bytes”
Rick Graziani graziani@cabrillo.edu 5
ASCII-8
• IBM later extended the
1
standard, using 8 bits per
byte.
• This was known as
Extended ASCII or ASCII-8
• This gave 256 unique
combinations of 0’s and 1’s.
0 = 00000000
1 = 00000001
2 = 00000010
3 = 00000011
… 255 = 11111111
Rick Graziani graziani@cabrillo.edu 6
ASCII-8
Rick Graziani graziani@cabrillo.edu 7
Try it! 1
• Write out Cabrillo College (Upper and Lower case) in bits (binary)
using the chart above.
0100 0010 0110 0001 …
C a
Rick Graziani graziani@cabrillo.edu 8
The answer! 1
0100 0011 0110 0001 0110 0010 0111 0010 0110 1001 0110 1100
C a b r i l
0110 1100 0110 1111 0010 0000 0100 0011 0110 1111 0110 1100
l o space C o l
0110 1100 0110 0101 0110 0111 0110 0101
l e g e
Rick Graziani graziani@cabrillo.edu 9
ASCII ART
• http://patorjk.com/software/taag/
Rick Graziani graziani@cabrillo.edu 10
Rick Graziani graziani@cabrillo.edu 11
Unicode
• Although ASCII works fine for English, many other languages need
more than 256 characters, including numbers and punctuation.
• Unicode uses a 16 bit representation, with 65,536 possible symbols.
• Unicode can handle all languages.
• www.unicode.org
Rick Graziani graziani@cabrillo.edu 12
Non-text Files:
Representing Images and Sound
Rick Graziani graziani@cabrillo.edu 14
Rick Graziani graziani@cabrillo.edu 15
Pixels
• A monitors screen is divided into a grid of small unit called
picture elements or pixels.
• The more pixels per inch the better the resolution, the
sharper the image.
• All colors on the screen are a combination of red, green
and blue (RGB), just at various intensities.
Rick Graziani graziani@cabrillo.edu 16
Rick Graziani graziani@cabrillo.edu 17
• Each Color intensity of red, green and blue represented as a
quantity from 0 through 255.
• Higher the number the more intense the color.
• Black has no intensity or no color and has the value (0, 0, 0)
• White is full intensity and has the value (255, 255, 255)
• Between these extremes is a whole range of colors and intensities.
• Grey is somewhere in between (127, 127, 127)
Rick Graziani graziani@cabrillo.edu 18
RGB Colors and Binary Representation
• You can use your favorite program that allows you to choose colors to
view these various red, green and blue values.
Rick Graziani graziani@cabrillo.edu 19
RGB Colors and Binary Representation
• Let’s convert these colors from Decimal to Binary!
Red Green Blue
Purple: 172 73 185
Gold: 253 249 88
Rick Graziani graziani@cabrillo.edu 20
RGB Colors and Binary Representation
Red Green Blue
Purple: 172 73 185
Gold: 253 249 88
Number of:
27 26 25 24 23 22 21 20
128’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s
Dec.
172
73
185
253
249
88
Rick Graziani graziani@cabrillo.edu 21
RGB Colors and Binary Representation
Red Green Blue
Purple: 172 73 185
Gold: 253 249 88
Number of:
27 26 25 24 23 22 21 20
128’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s
Dec.
172 1 0 1 0 1 1 0 0
73 0 1 0 0 1 0 0 1
185 1 0 1 1 1 0 0 1
253 1 1 1 1 1 1 0 1
249 1 1 1 1 1 0 0 1
88 0 1 0 1 1 0 0 0
Rick Graziani graziani@cabrillo.edu 22
RGB Colors and Binary Representation
• We have now converted these colors from Decimal to Binary!
Red Green Blue
Purple: 172 73 185
10101100 01001001 10111001
Gold: 253 249 88
11111101 11111001 01011000
• Why does this matter?
Rick Graziani graziani@cabrillo.edu 23
First a word about Pixels Per Inch
1600 pixels
1200 pixels/300 ppi = 4 inches 1600 pixels /300 ppi = 5.3 inches
1200
pixels
graphicssoft.about.com
• PPI stands for pixels per inch.
• PPI is a measurement of image resolution that defines the
size an image will print.
• The higher the PPI value, the better quality print you will
get--but only up to a point.
• 300ppi is generally considered the point of diminishing
returns when it comes to ink jet printing of digital photos.
Rick Graziani graziani@cabrillo.edu 24
First a word about Pixels Per Inch
• The higher the PPI value,
the better quality print you
will get--but only up to a
point.
Rick Graziani graziani@cabrillo.edu 25
RGB Colors and Binary Representation
Red Green Blue
Purple: 172 73 185
10101100 01001001 10111001
24 bits for one pixel!
• “True color” systems require 3 bytes or 24 bits per pixel.
• There is 8 bit and 16 bit color, which gives you less of a color palette.
Rick Graziani graziani@cabrillo.edu 26
RGB Colors and Binary Representation
8 inches or 10 inches or
2,400 pixels 3,000 pixels
Red Green Blue
Purple: 172 73 185
10101100 01001001 10101111 = 24 bits per pixel
• An 8 inch by 10 inch image scanned in at 300 pixels per inch:
– 8 x 300 = 2,400 pixels 10 x 300 = 3,000 pixels
– 2,400 pixels by 3,000 pixels = 7,200,000 pixels or 7.2 megapixels
– At 24 bits per pixel (7,200,000 x 24)
• = 172,800,000 bits or 21,600,000 bytes (21.6 megabytes)
• RAM memory, video memory, disk space, bandwidth,…
Rick Graziani graziani@cabrillo.edu 27
File Compression
• Typical computer screen only has
about 100 pixels per inch, not
300.
• Images still require a lot of
memory and disk space, not to
mention transferring images over
the network or Internet.
• Compression – A means to
change the representation to use
fewer bits to store or transmit
information.
• Information sent via a fax is either
black or white, long strings of 0’s
or long strings of 1’s.
Rick Graziani graziani@cabrillo.edu 28
Run-length encoding
• Many fax machines use run-length
encoding.
• Run-length encoding uses binary
numbers to specify how long the
first sequence (run) of 0’s is, then
how long the following sequence of
1’s is, then how long the following
sequence of 0’s is, and so on.
• Fewer bits needed than sending
100 0’s, then 373 1’s etc.
• Run-length encoding is a lossless
compression scheme, meaning
that the original representation of
0’s and 1’s can be reconstructed
exactly.
Rick Graziani graziani@cabrillo.edu 29
JPEG
Compression
• JPEG – Joint Photographic Experts Group
• JPEG is a common standard for compressing and storing still images.
• Our eyes are not very sensitive to small changes in hue (chrominance),
but we are sensitive to brightness (luminance).
• This means we can store less accurate description of the hue of the
picture (fewer bits) and our eyes will not notice it.
• This is a lossy compression scheme, because we have lost some
the original representation of the image and it cannot be reconstructed
exactly.
Rick Graziani graziani@cabrillo.edu 30
JPEG Compression Scheme
• With JPEG we can get 20:1 compression ratio or more, without being
able to see a difference.
• There are large areas of similar hues in pictures that can be lumped
together without our noticing.
• Because of this, when Run-length compression is used there is more
compression because there is less variations in the hue.
Rick Graziani graziani@cabrillo.edu 31
RAW vs JPEG
• http://www.youtube.com/watch?v=Qsi71MEFPB8&feature=rel
Rick ated
Graziani graziani@cabrillo.edu 32
MPEG Compression Scheme
• MPEG (Motion Pictures Experts Group)
• MPEG compression is similar to JPEG, but applied to movies.
– JPEG compression is applied to each frame.
– Then interframe coherency is used, which only records and
transmits the “differences” between frames.
Rick Graziani graziani@cabrillo.edu 33
Hexadecimal Number System
<tr>
<td rowspan="2" bgcolor="#cccc99"> </td>
<td height="30" bgcolor="#999966"><div id="mainnav">
Rick Graziani graziani@cabrillo.edu 35
Rick Graziani graziani@cabrillo.edu 36
Pixels
• A monitors screen is divided into a grid of small unit called
picture elements or pixels.
• The more pixels per inch the better the resolution, the
sharper the image.
• All colors on the screen are a combination of red, green
and blue (RGB), just at various intensities.
Rick Graziani graziani@cabrillo.edu 37
Rick Graziani graziani@cabrillo.edu 38
Dreamweaver
Rick Graziani graziani@cabrillo.edu 39
<tr>
<td rowspan="2" bgcolor="#cccc99"> </td>
<td height="30" bgcolor="#999966"><div id="mainnav">
Hexadecimal Number
• With web applications like HTML (Hypertext Markup
Language), colors are sometime described using their RGB
color specification in hexadecimal.
Rick Graziani graziani@cabrillo.edu 40
Hexadecimal RED GREEN BLUE
<td rowspan="2" bgcolor="#cccc99"> </td>
Red Green Blue
cc cc 99
<td height="30" bgcolor="#999966"><div id="mainnav">
Red Green Blue
99 99 66
# means hexadecimal in web applications
Rick Graziani graziani@cabrillo.edu 41
Hexadecimal Numbers
• What are they?
• Why do these people use them?
– web designers
– digital medial creators
– computer scientists
– networking professionals
Rick Graziani graziani@cabrillo.edu 42
Rick’s Number System Rules
• All digits start with 0
• A Base-n number system has n number of digits:
– Decimal: Base-10 has 10 digits
– Binary: Base-2 has 2 digits
– Hexadecimal: Base-16 has 16 digits
• The first column is always the number of 1’s
• Each of the following columns is n times the previous
column (n = Base-n)
– Base 10: 10,000 1,000 100 10 1
– Base 2: 16 8 4 2 1
– Base 16: 65,536 4,096 256 16 1
Rick Graziani graziani@cabrillo.edu 43
Hexadecimal Digits
Hexadecimal: 16 digits
Dec Hex Dec Hex
0 0 8 8
1 1 9 9
2 2 10 A
3 3 11 B
4 4 12 C
5 5 13 D
6 6 14 E
7 7 15 F
Rick Graziani graziani@cabrillo.edu 44
0, 1, 2, 3, 4, 5, 6, 7 ,8, 9, A, B, C, D, E, F
Hexadecimal
Decimal 16’s 1’s
8 8
9 9
10 A
14 E
15 F
16 1 0
Rick Graziani graziani@cabrillo.edu 45
0, 1, 2, 3, 4, 5, 6, 7 ,8, 9, A, B, C, D, E, F
Hexadecimal
Decimal 16’s 1’s
17 1 1
20 1 4
21 1 5
26 1 A
12 C
29 1 D
Rick Graziani graziani@cabrillo.edu 46
0, 1, 2, 3, 4, 5, 6, 7 ,8, 9, A, B, C, D, E, F
Hexadecimal
Decimal 16’s 1’s
30 1 E
31 1 F
32 2 0
33 2 1
50 3 2
60 3 C
Rick Graziani graziani@cabrillo.edu 47
Answer these
• Rick is 53 years old in decimal. How old is Rick in Hexadecimal?
Decimal 16’s 1’s
52 3 5
48 + 4
• McLuigi went into a bar and ordered a beer. The bartender ask McLuigi
for his ID to make sure he was old enough to order a beer (21). After
looking at McLuigi’s ID the bartender told McLuigi he was not at least
21. McLuigi answered, “Wrong laddie, I am exactly 21. My ID shows
my age in Hexadecimal.”
What age is on McLuigi’s ID in Hexadecimal?
Decimal 16’s 1’s
21 1 5
16 + 5
Rick Graziani graziani@cabrillo.edu 48
One more
• Rick’s mom was having her 80th birthday but she didn’t like
the fact that she was getting so “old”. So, Rick and his
brother Frank (the smart Physicist) decided to celebrate
her birthday in Hexadecimal.
• What age did it say on her birthday cake?
Happy 5 0 th Birthday!
Rick Graziani graziani@cabrillo.edu 49
Don’t forget why we are doing this!
<tr>
<td rowspan="2" bgcolor="#cccc99"> </td>
<td height="30" bgcolor="#999966"><div id="mainnav">
Hexadecimal Number
Rick Graziani graziani@cabrillo.edu 50
Why Hexadecimal?
• Hexadecimal is perfect for matching 4 bits.
• Every combination of 4 bits can be matched with
one hex number.
• 4 bits can be represented by 1 Hex value
• 8 bits can be represented by 2 Hex values
Rick Graziani graziani@cabrillo.edu 51
Hexadecimal Digits
4 bits can be represented by 1 Hex value
Hexadecimal: 16 digits
Dec Hex Binary Dec Hex Binary
8421 8421
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
Rick Graziani graziani@cabrillo.edu 52
Hexadecimal Digits
4 bits can be represented by 1 Hex value
• Hexadecimal is perfect for matching 4 bits.
• Every combination of 4 bits can be matched with one hex number.
• 4 bits can be represented by 1 Hex value
• 8 bits can be represented by 2 Hex values
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
Rick Graziani graziani@cabrillo.edu 53
Converting Decimal, Hex, and Binary
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
Dec. Hex Binary Dec. Hex Binary Dec. Hex Binary
0 0010 10
F 1110 12
A 0000 5
C 0010 1000
Rick Graziani graziani@cabrillo.edu 54
Converting Decimal, Hex, and Binary
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
Dec. Hex Binary Dec. Hex Binary Dec. Hex Binary
0 0 0000 2 2 0010 10 A 1010
15 F 1111 14 E 1110 12 C 1100
10 A 1010 0 0 0000 5 5 0101
12 C 1100 2 2 0010 8 8 1000
Rick Graziani graziani@cabrillo.edu 55
What about 8 bits?
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
HEX BINARY
2 4 ?
Rick Graziani graziani@cabrillo.edu 56
What about 8 bits?
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
HEX BINARY
2 4 0010 0100
Rick Graziani graziani@cabrillo.edu 57
Using Hex for 8 bits
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
Hex Binary Hex Binary Hex Binary
12 0001 0010 3C 99
AB 1A 00
02 B4 7D
0111 0111 1000 1111 1111 1111
0000 0010 1100 1001 0101 1100
Rick Graziani graziani@cabrillo.edu 58
Using Hex for 8 bits
Dec. Hex. Binary Dec. Hex. Binary
0 0 0000 8 8 1000
1 1 0001 9 9 1001
2 2 0010 10 A 1010
3 3 0011 11 B 1011
4 4 0100 12 C 1100
5 5 0101 13 D 1101
6 6 0110 14 E 1110
7 7 0111 15 F 1111
-----------------------------------------------------
Hex Binary Hex Binary Hex Binary
12 0001 0010 3C 0011 1100 99 1001 1001
AB 1010 1011 1A 0001 1010 00 0000 0000
02 0000 0010 B4 1011 0100 7D 0111 1101
77 0111 0111 8F 1000 1111 FF 1111 1111
02 0000 0010 C9 1100 1001 5C 0101 1100
Rick Graziani graziani@cabrillo.edu 59
So why is Rick torturing us?
<tr>
<td rowspan="2" bgcolor="#cccc99"> </td>
<td height="30" bgcolor="#999966"><div id="mainnav">
Hexadecimal Number
Rick Graziani graziani@cabrillo.edu 60
How much RED GREEN BLUE ?
<td rowspan="2" bgcolor="#cccc99"> </td>
Red Green Blue
cc cc 99
<td height="30"bgcolor="#999966"><divid…>
Red Green Blue
99 99 66
Rick Graziani graziani@cabrillo.edu 61
Hexadecimal # RED GREEN BLUE
<td rowspan="2" bgcolor="#cccc99"> </td>
Red Green Blue
cc cc 99
Convert to Binary
Red Green Blue
Hex cc cc 99
Bin 1100 1100 1100 1100 1001 1001
24 bits represent a single color
Rick Graziani graziani@cabrillo.edu 62
Red Green Blue
Hex cc cc 99
Bin 1100 1100 1100 1100 1001 1001
24 bits represent a single color
Rick Graziani graziani@cabrillo.edu 63
Red Green Blue
Hex 00->FF 00->FF 00->FF
Bin 0000 0000 0000 0000 0000 0000
thru thru thru
1111 1111 1111 1111 1111 1111
Dec 0 -> 255 0 -> 255 0 -> 255
255 255 255
? ? ?
0 0 0
Rick Graziani graziani@cabrillo.edu 64
255
?
0
255
?
0
255
How Much?
? 0 to 255
0
Rick Graziani graziani@cabrillo.edu 65
Red Green Blue
Hex cc cc 99
Bin 1100 1100 1100 1100 1001 1001
Hexadecimal
Decimal 16’s 1’s
c c
or
12 12
(12x16) (12x1)
204 = 192 + 12
Rick Graziani graziani@cabrillo.edu 66
Red Green Blue
Hex cc cc 99
Bin 1100 1100 1100 1100 1001 1001
Dec 204 204 153
Rick Graziani graziani@cabrillo.edu 67
255
204
0
255
204
0
255
153
0
Rick Graziani graziani@cabrillo.edu 68
<td rowspan="2" bgcolor="#cccc99"> </td>
Rick Graziani graziani@cabrillo.edu 69
www.december.com
• For those of you interested in Web Design and Digital
Media, you will work with colors based on hexadecimal
code, hue, other codes, or shades.
• http://www.december.com/html/spec/color.html
Rick Graziani graziani@cabrillo.edu 70
Chili
Powder
#C73F17
C 7 3 F 1 7
16’s 1’s 16’s 1’s 16’s 1’s
12 7 3 15 1 7
12x16 7x1 3x16 15x1 1x16 7x1
192 + 7 48 + 15 16 + 7
199 63 23
Rick Graziani graziani@cabrillo.edu 71
Chili
Powder
#C73F17
C7 3F 17
199 63 23
Rick Graziani graziani@cabrillo.edu 72
Deleted the next two slides for you enjoyment.
Rick Graziani graziani@cabrillo.edu 73
Color Codes
Rick Graziani graziani@cabrillo.edu 74
Digitizing Sound
Theme from Shaft
Rick Graziani graziani@cabrillo.edu 76
Digitizing Sound
• Many definitions of analog.
• (Our definition) analog wave is a wave form analogous to the human
voice.
• The telephone systems uses an analog wave to transmit your voice
over the telephone line to their Central Office.
Rick Graziani graziani@cabrillo.edu 77
Digitizing Sound
• Two parts of the wave:
– Amplitude – Height of the wave which equates to volume.
– Frequency – Number of waves per second, which equates to pitch.
• Computers are digital devices, so the analog wave needs to be
converted to a digital format.
Rick Graziani graziani@cabrillo.edu 78
Digitizing Sound
• Converting Analog to Digital requires three steps:
1. Sampling
2. Quantifying
3. Coding
Rick Graziani graziani@cabrillo.edu 79
Digitizing Sound
• Sampling – To take measurements at regular intervals.
• The more samples you take, the more accurately you represent the
original wave, and the more accurately you can reproduce the original
wave.
Rick Graziani graziani@cabrillo.edu 80
Digitizing Sound
1 second, 40,000 samples
• Nyquist’s Theorem which states that a sampling of two times the
highest allowable frequency is sufficient for reconstructing an analog
wave into a digital data.
• Human can hear frequencies up to about 20,000 Hz or 20,000
frequencies per second.
• Using Nyquist’s Theorem, this means we need to sample each analog
wave at 40,000 times per second of sound.
• In other words, each one second of sound gets sample 40,000 times.
(Actually, 44,100 times per second.)
Rick Graziani graziani@cabrillo.edu 81
Digitizing Sound
• Quantifying – This is the process of giving a value to each of the
samples taken.
• The larger the range of numbers, the more detailed or specific you can
be in your quantifying.
Rick Graziani graziani@cabrillo.edu 82
Digitizing Sound
• Coding – This is the process taking the value quantified and
representing it as a binary number.
• Audio CDs use 16 bits for coding.
• 16 bits gives a range from 0 to 65,536.
• Actually:
– 15 bits are used for the range of numbers
– 1 bit is used for + (positive) or – (negative)
• 32,768 positive values and 32,768 negative values
• How many bits does it take to record one minute of digital audio?
Rick Graziani graziani@cabrillo.edu 83
Digitizing Sound
• How many bits does it take to record one minute of digital audio?
• 1 minute = 60 seconds
• 44,100 samples per second
• This equals 2,646,000 samples.
• Each sample requires 16 bits.
• 2,646,000 samples times 16 bits per sample equals 42,336,000 bits.
• 42,336,000 bits times 2 for stereo equals 84,672,000 bits for 1 minute
of audio.
• 84,672,000 bits divided by 8 bits per byte equals 10,584,000 bytes for
1 minute of audio. (More than 10 megabytes!)
• One hour of audio equals 635,040,000 bytes or 635 MB (megabytes)!
Rick Graziani graziani@cabrillo.edu 84
MP3 Compression
• Compressing digital audio means to reduce the number of bits needed
to represent the information.
• There are many sounds, frequencies, that the human ear cannot hear,
some too high, some too low.
• These waves can be removed without impacting the quality of the
audio.
• MP3 uses this sort of compression for a typical compression ratio of
10:1, so a one minute of MP3 music takes 1 megabyte instead of 10
megabytes.
Rick Graziani graziani@cabrillo.edu 85
Suggested music for your enjoyment…
• Couple of the first concerts I ever went to…
Rick Graziani graziani@cabrillo.edu 86
Advantage of Digitizing Information
• A key advantage to digital representation of information,
images and sounds, is that the it can be reproduced
exactly without losing a “bit” of the quality.
Rick Graziani graziani@cabrillo.edu 87
Data Storage – Part 2
CS 1 Introduction to Computers and Computer
Technology
Rick Graziani
Fall 2010
