Digital Multimedia

Day 6

Agenda

  • Sound
    • Sound as waves
    • Digitizing sound
    • Compression
    • MIDI
    • Sound editing
      • Audacity demo

Sound as waves

  • Amplitude
  • Frequency
    (20 Hz - 20 kHz)
  • Waveforms
  • Perception

Digitizing sound

  • Sampling
  • Quantization
  • Dithering

Compression

  • Speech compression
    • Companding
      (non-linear quantization)

Compression

  • Perceptually based compression
    • Threshold for hearing
    • Masking tones

MIDI

  • A digital orchestra
  • Think sheet music
  • General MIDI provides 128 voice names

Sound editing

  • Audacity demo