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Audio & Sound Necessary Multimedia Vocabulary #4. Journalism 108. .AIFF. Audio Interchange File Format A standard digital audio file on the Macintosh and some Windows computers. .MP3. A digital audio format popular on the Internet. .WAV.
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Audio & SoundNecessary Multimedia Vocabulary #4 • Journalism 108
.AIFF • Audio Interchange File Format • A standard digital audio file on the Macintosh and some Windows computers
.MP3 • A digital audio format popular on the Internet.
.WAV • A .WAV sound file is most often used on the Windows platform. It is also acceptable on the Macintosh. Therefore it is a good choice for crossplatform compatible sound files. • We will use .WAV files for some sounds on our multimedia projects.
QuickTime Sound-Only Movie • The QuickTime format, most often used for digital video, is also an efficient method of digitizing sound. • .MOV files.
Compressed Sound • A sound file that has been altered so that it requires less memory. • Compressing a sound always reduces sound quality. • Generally, the higher the compression ratio, the lower the sound quality. • We will not be using compressed sounds in our multimedia project.
Decibels (dB) • Units for measuring sound level differences.
Sound Quality • Determined by • quality of source sound. • quality of analog capture device. • sampling rate when digitized. • sampling resolution when digitized. • compression ratio (if any) when digitized.
Sampling Rate • The number of sampling intervals per second used to capture a sound when it is digitized. • The higher the sampling rate, the higher the quality. • The computer (as well as audio CDs) are capable of sampling at greater than 44,100 cycles a second.
Dynamic Range • Determined by the sampling resolution. • The difference between the loudest sound and the softest sound that can be recorded without distortion. • 8-bit sounds have a dynamic range of 48 dB • 16-bit sounds have 96 dB. • Human hearing ranges from silence to 120 dB
Downsampled Sound • A sound that has been converted to a lower sampling rate. • Decreases the memory required to store the sound, but reduces sound quality.
Waveform • A graphic representation of a sound. • The height of the waveform represents the amplitude, or loudness.
Amplify • To adjust the strength or loudness of a sound.
Wavelength (period) • The distance between two successive peaks in a waveform. • The number of wavelength per second is the “frequency.”
Frequency • The number of wave peaks or cycles in one second. • Specified in hertz (Hz) or kilohertz (kHz). • Also know as “Pitch” when applied to our perception of sound.