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AUDIO MEDIA

AUDIO MEDIA.

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AUDIO MEDIA

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  1. AUDIOMEDIA

  2. “Sound also adds to the interpretation of the text. If you are an audio learner, you key in on the sounds as much as you key in on the graphics and text. No matter what type of learner you are, the addition of audio will increase your learning productivity. The Audio sub-topic presents information on various phases of audio including how we hear, wave forms, digital audio techniques, sound types, and audio file formats. As you study this section, think about the different types of sound, how they are created, and how you might use sounds in a multimedia project.” (Sprankle and Johnson)

  3. “Speech in the form of narration or dialog can teach effectively in your multimedia application. To enhance the direct statements, a speech segment can also convey meaning through: Emphasis. Emphasis increases when a speaker stress a word  Inflection. Inflection alters the pitch or tone of spoken language such as a rise in pitch at the end of a sentence to indicate a question.  Aural mood. Speech establishes aural mood through specific word choices such as crashed versus hit or fantastic versus good.” (Fenrich, 1997, p.129)

  4. When dealing with audio media, there are two different approaches to recording, saving, and playing these media: sound voice music RecordedSound

  5. When dealing with audio media, there are two different approaches to recording, saving, and playing these media: sound voice music RecordedSound Music Synthesized Music

  6. AUDIO FILE FORMATS

  7. Waveform Formats • .WAVe(PC) • .AIFf(Mac) • .AUdio (Sun - Unix & PC) • Others Synthesized Formats • .MIDi(PC & Mac) • .RMI (PC) See Table 5-4 for a comprehensive list of audio formats

  8. When dealing with sound, there are 3 factors. 1. # of channels 2. Sampling rate 3. # of bits of sound

  9. Mono - 1 channel (track) Stereo - 2 channels (tracks) Sound

  10. 1 second Sound Continuous(analog)

  11. 1 second Sound Sampled 25/sec. (digital)

  12. Sound Human hearing 20 - 20,000 cps (Hz) 8 bits of sound 28 = 256 different frequencies 19,980 / 256 = 78 cps steps

  13. Sound Human hearing 20 - 20,000 cps (Hz) 8 bits of sound 28 = 256 different frequencies 19,980 / 256 = 78 cps steps 16 bits of sound 216 = 65,536 different freq. 19,980 / 65,536 = .3 cps steps

  14. Sound .WAVefiles (record/play sound waves) voice - 11,025 times/sec. sampling rate 8 bit sound mono 3.5” HD diskette holds 131 sec.

  15. Sound .WAVefiles (record/play sound waves) CD - 44,100 times/sec. sampling rate 16 bit sound stereo 3.5” HD diskette holds 8 sec.

  16. Sound .MIDifiles (synthesize musical instruments) Like sheet music frequency duration “voice” - (piano, drums, guitar, sax) 94 second score is only 28k See Table 5-3 for a comprehensive list of voices

  17. WAVe vs. MIDi Although waveform files allow the recording, editing, and playback of sound, voice, and music, they usually require large file sizes. A typical voice recording in mono and with an 11 K sampling rate requires approximately 11,000 bytes/second and a CD quality recording in stereo with a 44k sampling rate requires approximately 176,000 bytes/second. Whereas, a typical MIDI file requires approximately 200 bytes/second! However, MIDI files can only contain the instructions to play music, and the creation of a MIDI file requires a MIDI device (keyboard) and musical talent. However, you can find MIDI editors on the Internet.

  18. AUDIO SOFTWARE

  19. Audio Software Media Player(Windows) - player for WAV, WMA, MID, and many other audio file types. Sound Recorder(Windows) - player, recorder, and limited editor for WAV files. (Only a recorder with Vista.) Goldwave (www.goldwave.com) - editor, player, recorder, and converter for numerous audio file types. Audactiy (audacity.sourceforge.net) - editor, player, recorder, and converter for numerous audio file types.

  20. Consider the following example:

  21. When I was using PowerPoint 97, I wanted to use DIESEL.AU, a file that I found on the Internet as a sound effect in my presentation. However, PowerPoint 97 only plays WAVe files, and the file was too long (48 seconds).

  22. 48 seconds

  23. 14 seconds

  24. } Created } “Borrowed” Audio Sources • Microphone • MIDI keyboard • CD’s & disks • Internet

  25. # of bits sampling rate uses File Size Considerations 8 11 KHz / Mono lowest standard that should be used 8 11 KHz / Stereo no advantage in using stereo 8 22 KHz / Mono sounds like AM radio 16 22 KHz / Mono okay for narrations 16 44 KHz / Stereo CD-quality sound See Table 5-2 for additional examples

  26. File Size Considerations Similar to what we saw with graphics files, depending on the format that is used, audio files can use different amounts of space. As an example, Diesel.AU requires 380Kbytes while Diesel.WAV requires 760 Kbytes. Although, AU files require less space, many applications are unable to use sound files in this format. compressed vs. uncompressed

  27. “Audio compression techniques can provide important benefits for applications stored on CD-ROMs and hard disks, since uncompressed audio requires significant storage space. Digital audio is fairly difficult to compress, and no standardized compression/decompression technique has yet emerged. Some sound boards can perform the relatively common ADPCM (Adaptive Differential Pulse Code Modulation) compression/decompression technique.” We can see which “codecs” are installed on a computer by going to Start, Settings, Control Panel, Sounds and Devices, Hardware tab, and scroll down to Audio Codecs. See ekei.com/audio/ for a discussion of compression algorithms. (Fenrich, 1997)

  28. Download vs. Streaming

  29. Download vs. Streaming Initial download “Buffered” ongoing download with simultaneous play back Software is needed to: create serve play Received first, then played Software is needed to: create play

  30. Audio (Downloaded) (Streamed) Sound .WAV .SND .AU …etc Music .MIDi .MP3 .RA/.RAM .ASF .MP3

  31. Addins and Helpers Plugins/Addins - Run ONLY inside of a browser.Macromedia Shockwave for Director Helpers - Run in, as well as outside of a browser.Adobe Acrobat Reader RealNetwork RealPlayer

  32. MP3 a challenge to CD’s???

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