Æliens

audio databases

• audio signals -- compression, discrete representation
• musical patterns -- similarity-based retrieval

audio data model

• meta-data -- describing content
• features -- using feature extraction

example

   singers -- (Opera,Role,Person)
   score -- ...
   transcript -- ...
  

signal-based content

• audio data -- $\%F(x)$ over time x
• wave -- period T, frequency $f\; =\; 1/T$
• velocity -- $v\; =\; w/T\; =\; w\; *\; f$, with $w$ wavelength
• amplitude -- a

windowing

• break signal up in small windows of time

feature extraction

• intensity -- watts/$m^2$
• loudness -- in decibels
• pitch -- from frequency and amplitude
• brightness -- amount of distortion

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