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04 audio

  1. 1. Êส‹‹Çว¹น»ปÃรÐะ¡กÍอºบÁมÑัÅลµตÔิÁมÕีàเ´ดÕีÂย [àเÊสÕีÂย§ง] 17 ÊสÔิ§งËหÒา¤คÁม 2553
  2. 2. ia Systems 520251: Multimed Êส‹‹Çว¹น»ปÃรÐะ¡กÍอºบÁมÑัÅลµตÔิÁมÕีàเ´ดÕีÂย [àเÊสÕีÂย§ง] 17 ÊสÔิ§งËหÒา¤คÁม 2553
  3. 3. Agenda • Properties of sound • Analog audio • Digital audio • Audio file formats • Sound recording • Sound editing
  4. 4. Introduction • Audio is the reproduction of sound - important means of communication. • There are a number of advantages of using audio. • most obvious: interface for visual disabilities
  5. 5. Properties of Sound • Sound is a pressure wave created by successively vibrating matter back and forth. • The sound wave is in the form of a sine wave.
  6. 6. Frequency • The number of air pressure oscillations per second at a fixed point by a sound wave • Measured in Hertz (Hz) - number of waves per second • Audible range (human) = 20 Hz - 20 kHz • this is where the sensation of pitch originates
  7. 7. Frequency & Pitch
  8. 8. Frequency & Pitch Frequency Pitch
  9. 9. Frequency & Pitch Frequency Pitch Frequency Pitch
  10. 10. Frequency & Pitch Frequency Pitch Frequency Pitch
  11. 11. Wavelength • The distance between waves
  12. 12. Amplitude • The height of the wave • Measured in decibels (dB or dBA)
  13. 13. Intensity vs. Loudness • Amplitude can be thought of as the intensity of sound and is measurable. • Loudness of sound is a perception. • Sound can be perceived differently at the various frequencies (1 kHz-4 kHz is more sensitive than the lower and the higher) • Individuals also have different hearing capacities. What is loud to one person may not be loud to another, which why loudness is a perception and cannot be measured.
  14. 14. dBA Sound 10 Normal breathing 20 Whispering at 5 ft 30 Soft whispering 50 Rainfall 60 Normal conversation 110 Shouting in the ear 120 Thunder 110-120 Rock concert 130 Air raid 180 Rocket launching from pad
  15. 15. Analog Audio • analog = the measurement of continuous change or movement over a period of time
  16. 16. Digital Audio • The reproduction of sound using digital information • The value of the signal is sampled at regular intervals by an analog-to-digital converter (ADC)
  17. 17. Basic Terminology & Properties of DA • Channels • Sampling rate • Bit depth • Quality and file size • Compression • Audio codecs
  18. 18. Channels Stereo Mono
  19. 19. Channels Stereo e s se d l c om p r i le w i l An u n gi t a l f e o di e s i ze o f a s te r c e t h b e t w i n o f i le . mo Mono
  20. 20. Sampling Rate • ADC - the signal is sampled at regular intervals • The value of each sample is rounded to the nearest integer in a scale that varies according to the resolution of the signal
  21. 21. Sampling Rate • The accuracy the reproduction to the source depends on how often the sample is taken.
  22. 22. Common DA Sampling Rate 8,000 Hz telephone, adequate for human speech 22,050 Hz radio 32,000 Hz miniDV digital camcorder CD, commonly used with MPEG-1 audio 44,100 Hz (VCD, SVCD, MP3) digital sound used for digital TV, DVD, DAT, 48,000 Hz films and professional audio 96,000 or 192,400 Hz DVD-audio and HD-DVD audio tracks
  23. 23. Bit Depth • The number of bits used to describe each of the samples taken from the sampling rate • the potential accuracy of a digital audio • Higher bit-depth audio will sound better than lower one
  24. 24. Quality & File Size • Make the highest level (if possible) ~ 16-bit 44kHz Stereo • this produces a large file size, however, high audio clarity • Chances to manipulate such file (to make it smaller) : • reduce the sampling rate • make it mono
  25. 25. Compression • Digital audio files can also be compressed to reduce file size • MPEG-1 Audio layer-3 (MP3) is a common
  26. 26. Compression • Digital audio files can also be compressed to reduce file size • MPEG-1 Audio layer-3 (MP3) is a common
  27. 27. Compression Audio Quality • Digital audio files can also be compressed to reduce file size • MPEG-1 Audio layer-3 (MP3) is a common
  28. 28. Compression Audio Quality • Digital audio files can also be compressed to reduce file size • MPEG-1 Audio layer-3 (MP3) is a common
  29. 29. Compression Audio Quality • Digital audio files can also be compressed to reduce file size • MPEG-1 Audio layer-3 (MP3) is a common File Size
  30. 30. Compression Audio Quality • Digital audio files can also be compressed to reduce Lossless file size WMA • MPEG-1 Audio layer-3 (MP3) is a common File Size
  31. 31. Compression Audio Quality • Digital audio files can also be compressed to reduce Lossless file size WMA Lossy • MPEG-1 Audio layer-3 MP3 Real Audio (MP3) is a common File Size
  32. 32. Compression Audio Quality “later editing” • Digital audio files can also be compressed to reduce Lossless file size WMA Lossy • MPEG-1 Audio layer-3 MP3 Real Audio (MP3) is a common File Size
  33. 33. Compression Audio Quality “later editing” • Digital audio files can also be compressed to reduce Lossless file size WMA Lossy • MPEG-1 Audio layer-3 MP3 Real Audio (MP3) is a common “transmission” File Size
  34. 34. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system.
  35. 35. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system.
  36. 36. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x
  37. 37. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x
  38. 38. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x
  39. 39. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y
  40. 40. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y
  41. 41. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y ✘
  42. 42. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y ✘ codec x
  43. 43. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y ✘ codec x ✔
  44. 44. Audio Codecs • An audio codec is a piece of software (coder/decoder) or a driver that provides support for certain audio formats for certain system. codec x codec y ✘ Audio codecs codec x ✔
  45. 45. Audio File Formats • An audio file format is a container format for storing • WAV format data on a computer system. • Microsoft’s audio format • AIF format • also one of the mostthe common format on • developed by Apple Computer web • MP3 • supported by most web browsers • most widespread form of audio on the Internet • AU format • playable on various • one of theformat on the common most players web • created by Sun Microsystems
  46. 46. MIDI Format • Musical Instrument Digital Interface (MIDI) is typically used to play music. • MIDI files contain a set of instruction that the computer sends to a sound card, synthesizer, or other device. • Such instructions (note and instrument description) describe how to play the sound, rather than recording an actual rendition of the sound.
  47. 47. Sound Recording
  48. 48. Sound Recording
  49. 49. Sound Recording
  50. 50. Sound Recording
  51. 51. Sound Recording
  52. 52. Sound Recording
  53. 53. Sound Editing • Audacity - it’s GNU GPL license, it’s free, it’s cross platform. • Tracks • Waveform display • Selection • Trim • Amplify • Pitch • and many more....
  54. 54. Digital Audio Technologies & Applications
  55. 55. Portable Music Players
  56. 56. Before Digital
  57. 57. Before Digital 70s
  58. 58. Before Digital 70s
  59. 59. Before Digital 70s
  60. 60. CD on market (1982)
  61. 61. CD on market (1982) D ig i t al! I t ’s
  62. 62. Not quite portable, is it?
  63. 63. Digital files? Compress ‘em
  64. 64. Digital files? Compress ‘em CODECS
  65. 65. Digital files? Compress ‘em ATRAC WMA CODECS Vorbis (OGG) AAC
  66. 66. Digital files? Compress ‘em CODECS MP3
  67. 67. Digital Audio Players
  68. 68. Digital Audio Players 1997 - MPMan SaeHan Infomation Systems Eiger Labs MPMAN F10 (1998) 32 MB
  69. 69. Digital Audio Players 1997 - MPMan 1998 - Rio PMP300 SaeHan Infomation Systems Diamond Multimedia Eiger Labs MPMAN F10 (1998) 32 MB Internal Memory 32 MB SmartMedia Memory Slot
  70. 70. Digital Audio Players
  71. 71. Digital Audio Players 2000 - Creative NOMAD Jukebox Creative Labs 6 GB Harddisk $500
  72. 72. The Revolution
  73. 73. The Revolution
  74. 74. The Revolution October 2001 - 1st iPod Introducing
  75. 75. iPod Family
  76. 76. Get quick and instant access to Tune into all your favorite stations Watch supported 720p HD movies, Connect, update, and buy content Surf the web anytime, anywhere your content with multi-touch with crystal-clear reception. With TV shows and videos in high wirelessly from Wi-Fi hot spots. you have a Wi-Fi connection. navigation. With a 3.3-inch screen an integrated HD Radio receiver, definition on your HDTV through Stream millions of songs over Wi- Enjoy your favorite websites with a and vivid 16:9 OLED display you can access a variety of HD the Zune HD & AV Dock (sold Fi directly to your Zune HD and full-featured web browser including (480x272 resolution), premium Radio stations at no additional separately). Or take them with you turn it into a portable digital tap-to-zoom technology, built-in entertainment is at your fingertips.* cost. Plus, tag the songs you like for premium entertainment on the jukebox. accelerometer, and touchscreen for later purchase. go. Additional dock and HDTV are QWERTY keyboard. required.*
  77. 77. iTunes + iTunes Music Store
  78. 78. Online Music Stores
  79. 79. Podcast
  80. 80. AudioBooks
  81. 81. Text-to-Speech
  82. 82. สถิติผู้พิการ 2550 ที่มา: สํานักงานสถิติแห่งชาติ
  83. 83. DAISY (Digital Accessibility Information System)

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