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Text, Images, Video and Sound CS 1 Introduction to Computers and Computer Technology Rick Graziani Spring 2015.

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1 Text, Images, Video and Sound CS 1 Introduction to Computers and Computer Technology Rick Graziani Spring 2015

2 Rick Graziani graziani@cabrillo.edu2 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

3 Rick Graziani graziani@cabrillo.edu3 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

4 Rick Graziani graziani@cabrillo.edu4 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

5 Rick Graziani graziani@cabrillo.edu5 Bytes 1 byte (B) Kilobyte (KB) = 1,024 bytes (2 10 ) “one thousand bytes” 1,024 = 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 Megabyte (MB) = 1,048,576 bytes (2 20 ) “one million bytes” Gigabyte (GB) = 1,073,741,824 bytes (2 30 ) “one billion bytes”

6 Wikipedia Rick Graziani graziani@cabrillo.edu6

7 7 ASCII-8 IBM later extended the 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 1

8 Rick Graziani graziani@cabrillo.edu8 ASCII-8

9 Rick Graziani graziani@cabrillo.edu9 Try it! Write out Cabrillo College (Upper and Lower case) in bits (binary) using the chart above. 0100 0011 0110 0001 … C a 1

10 Rick Graziani graziani@cabrillo.edu10 The answer! 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 1

11 Rick Graziani graziani@cabrillo.edu11 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 Unicode

12 Non-text Files: Representing Images and Sound

13 Rick Graziani graziani@cabrillo.edu13

14 Rick Graziani graziani@cabrillo.edu14

15 Rick Graziani graziani@cabrillo.edu15 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.

16 Rick Graziani graziani@cabrillo.edu16

17 Rick Graziani graziani@cabrillo.edu17 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)

18 Rick Graziani graziani@cabrillo.edu18 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.

19 Rick Graziani graziani@cabrillo.edu19 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

20 Rick Graziani graziani@cabrillo.edu20 RGB Colors and Binary Representation Red Green Blue Purple: 172 73 185 Gold: 253 249 88 Number of: 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 128’s 64’s 32’s 16’s 8’s 4’s 2’s 1’s Dec. 172 73 185 253 249 88

21 Rick Graziani graziani@cabrillo.edu21 RGB Colors and Binary Representation Red Green Blue Purple: 172 73 185 Gold: 253 249 88 Number of: 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 128’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

22 Rick Graziani graziani@cabrillo.edu22 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?

23 Rick Graziani graziani@cabrillo.edu23 First a word about Pixels Per Inch 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. 1600 pixels 1200 pixels 1200 pixels/300 ppi = 4 inches 1600 pixels /300 ppi = 5.3 inches

24 Rick Graziani graziani@cabrillo.edu24 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.

25 Rick Graziani graziani@cabrillo.edu25 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.

26 Rick Graziani graziani@cabrillo.edu26 RGB Colors and Binary Representation 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,… 10 inches or 3,000 pixels 8 inches or 2,400 pixels

27 Rick Graziani graziani@cabrillo.edu27 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.

28 Rick Graziani graziani@cabrillo.edu28 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.

29 Rick Graziani graziani@cabrillo.edu29 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.

30 Rick Graziani graziani@cabrillo.edu30 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.

31 Rick Graziani graziani@cabrillo.edu31 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.

32 Hexadecimal Number System

33 Rick Graziani graziani@cabrillo.edu33

34 Rick Graziani graziani@cabrillo.edu34

35 Rick Graziani graziani@cabrillo.edu35 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.

36 Rick Graziani graziani@cabrillo.edu36

37 Rick Graziani graziani@cabrillo.edu37 Dreamweaver

38 Rick Graziani graziani@cabrillo.edu38 With web applications like HTML (Hypertext Markup Language), colors are sometime described using their RGB color specification in hexadecimal. Hexadecimal Number

39 Rick Graziani graziani@cabrillo.edu39 Hexadecimal RED GREEN BLUE RedGreenBlue cccc99 RedGreenBlue 999966 # means hexadecimal in web applications

40 Rick Graziani graziani@cabrillo.edu40 Hexadecimal Numbers What are they? Why do these people use them? –web designers –digital medial creators –computer scientists –networking professionals

41 Rick Graziani graziani@cabrillo.edu41 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

42 Rick Graziani graziani@cabrillo.edu42 Hexadecimal Digits Hexadecimal: 16 digits Dec Hex 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 Dec Hex 8 8 9 9 10 A 11 B 12 C 13 D 14 E 15 F

43 Rick Graziani graziani@cabrillo.edu43 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

44 Rick Graziani graziani@cabrillo.edu44 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

45 Rick Graziani graziani@cabrillo.edu45 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

46 Rick Graziani graziani@cabrillo.edu46 Question… Luigi went into a bar and ordered a beer. The bartender ask Luigi for his ID to make sure he was old enough to order a beer (21). After looking at Luigi’s ID the bartender told Luigi he was not at least 21. Luigi answered, “I’m sorry but you are wrong. 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

47 Rick Graziani graziani@cabrillo.edu47 Don’t forget why we are doing this! Hexadecimal Number

48 Rick Graziani graziani@cabrillo.edu48 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

49 Rick Graziani graziani@cabrillo.edu49 Hexadecimal Digits 4 bits can be represented by 1 Hex value Hexadecimal: 16 digits Dec Hex Binary 8421 0 0 0000 1 1 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 7 0111 Dec Hex Binary 8421 8 8 1000 9 9 1001 10 A 1010 11 B 1011 12 C 1100 13 D 1101 14 E 1110 15 F 1111

50 Rick Graziani graziani@cabrillo.edu50 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 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

51 Rick Graziani graziani@cabrillo.edu51 Converting Decimal, Hex, and 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

52 Rick Graziani graziani@cabrillo.edu52 Converting Decimal, Hex, and 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

53 Rick Graziani graziani@cabrillo.edu53 What about 8 bits? 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 ?

54 Rick Graziani graziani@cabrillo.edu54 What about 8 bits? 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

55 Rick Graziani graziani@cabrillo.edu55 Using Hex for 8 bits 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

56 Rick Graziani graziani@cabrillo.edu56 Using Hex for 8 bits 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

57 Rick Graziani graziani@cabrillo.edu57 So why is Rick torturing us? Hexadecimal Number

58 Rick Graziani graziani@cabrillo.edu58 How much RED GREEN BLUE ? RedGreenBlue cccc99 RedGreenBlue 999966

59 Rick Graziani graziani@cabrillo.edu59 Hexadecimal # RED GREEN BLUE RedGreenBlue cccc99 Convert to Binary Red GreenBlue Hex cc cc99 Bin 1100 1100 1100 1100 1001 1001 24 bits represent a single color

60 Rick Graziani graziani@cabrillo.edu60 Red GreenBlue Hex cc cc99 Bin 1100 1100 1100 1100 1001 1001 24 bits represent a single color

61 Rick Graziani graziani@cabrillo.edu61 Red GreenBlue 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 0 255 0 0 ?? ?

62 Rick Graziani graziani@cabrillo.edu62 0 255 ? How Much? 0 to 255 0 255 ? 0 ?

63 Rick Graziani graziani@cabrillo.edu63 Red GreenBlue Hex cc cc99 Bin 1100 1100 1100 1100 1001 1001 Hexadecimal Decimal 16’s 1’s c c or 12 12 (12x16) (12x1) 204 = 192 + 12

64 Rick Graziani graziani@cabrillo.edu64 Red GreenBlue Hex cc cc99 Bin 1100 1100 1100 1100 1001 1001 Dec 204 204 153

65 Rick Graziani graziani@cabrillo.edu65 0 255 204 0 255 0 204 153

66 Rick Graziani graziani@cabrillo.edu66

67 Rick Graziani graziani@cabrillo.edu67 0 255 0 0 0 0 Red Green Blue Dec 0 0 255 Hex 00 00 FF Bin 0000 0000 0000 0000 1111 1111 00 FF 00 FF 00 FF Hexadecimal Decimal 16’s 1’s

68 Rick Graziani graziani@cabrillo.edu68 0 255 200 0 255 0 48 127 Red Green Blue Dec 200 48 127 Hex c8 30 7F Bin 1100 1000 0011 0000 0111 1111 00 FF 00 FF 00 FF Hexadecimal Decimal 16’s 1’s

69 Rick Graziani graziani@cabrillo.edu69 0 255 74 0 255 0 132 40 Red Green Blue Dec 74 132 40 Hex 4A 84 28 Bin 0100 1010 1000 0100 0010 1000 00 FF 00 FF 00 FF Hexadecimal Decimal 16’s 1’s

70 Rick Graziani graziani@cabrillo.edu70 0 255 0 0 Red Green Blue Dec 255 255 255 Hex FF FF FF Bin 1111 1111 1111 1111 1111 1111 00 FF 00 FF 00 FF Hexadecimal Decimal 16’s 1’s

71 Rick Graziani graziani@cabrillo.edu71 0 255 50 0 255 0 128 60 Red Green Blue Dec 50 128 60 Hex 32 80 3C Bin 0011 0010 1000 0000 0011 1100 00 FF 00 FF 00 FF Hexadecimal Decimal 16’s 1’s

72 Rick Graziani graziani@cabrillo.edu72 CMYK - Cyan-Magenta-Yellow-Black From Wikipedia: The CMYK color model (process color, four color) is used in color printing. Comparisons between RGB displays and CMYK prints can be difficult, since the color reproduction technologies and properties are so different. A computer monitor mixes shades of red, green, and blue to create color pictures. There is no simple or general conversion formula that converts between them. Conversions are generally done through color management systems. Nevertheless, the conversions cannot be exact.

73 Rick Graziani graziani@cabrillo.edu73 Color Codes

74 Digitizing Sound

75 Theme from Shaft Rick Graziani graziani@cabrillo.edu75

76 Rick Graziani graziani@cabrillo.edu76 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.

77 Rick Graziani graziani@cabrillo.edu77 Digitizing Sound

78 Rick Graziani graziani@cabrillo.edu78 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.

79 Rick Graziani graziani@cabrillo.edu79 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.

80 Rick Graziani graziani@cabrillo.edu80 Digitizing Sound Converting Analog to Digital requires three steps: 1. Sampling 2. Quantifying 3. Coding

81 Rick Graziani graziani@cabrillo.edu81 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.

82 Rick Graziani graziani@cabrillo.edu82 Digitizing Sound 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.) 1 second, 40,000 samples

83 Sampling – Quantifying - Coding A digital audio processor is used to sample the analogue audio wave 44,100 times a second. This means, at every tick (44,100 times per second), the digital audio processor (sampling): –Determines the amplitude of the original very complex audio wave. –It records it as a 16 bit value (quantifying) –This means there are 65,536 possible values for this amplitude (coding): 32,767 values above zero 32,767 values below zero. –It does this sampling for the two channels of stereo as well. Rick Graziani graziani@cabrillo.edu83

84 Rick Graziani graziani@cabrillo.edu84

85 Rick Graziani graziani@cabrillo.edu85 If we sample at too low a rate, we may miss some peaks and troughs in the original audio and so the resulting waveform may sound completely different and muddy 1 2 3 4 5 6 -6 -5 -4 -3 -2 0

86 Rick Graziani graziani@cabrillo.edu86 1 2 -2 0 Here we've got a fairly high sample rate, but the measurements of the amplitude are pretty coarse.

87 Rick Graziani graziani@cabrillo.edu87 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.

88 Rick Graziani graziani@cabrillo.edu88 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?

89 Rick Graziani graziani@cabrillo.edu89 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)!

90 Rick Graziani graziani@cabrillo.edu90 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.

91 Rick Graziani graziani@cabrillo.edu91 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.

92 Text, Images, Video and Sound CS 1 Introduction to Computers and Computer Technology Rick Graziani


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