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Parametric coding

Parametric coding is a compression technology used for audio and speech whereby the audio or speech signal is represented by means of different parameters. These parameters are coded into a bitstream format. The decoder rebuilts the signal from these parameters.

The parameters that are used to describe the signal are a little bit different for audio and speech. Parameters that are used for audio are:

  • sinusoids,
    the tones that are in the signal,
  • transients,
    behaviour in time,
  • noise and,
  • stereo image

Parameters that are used for speech are:

  • pitch,
    the fundamental tones,
  • transient,
    the harmonics,
  • noise,

A parametric code is especially useful for low bit-rate audio and speech coding demanding medium to good quality. Parametric coding is used in low bit-rate audio and speech codecs like MPEG-4 HVCX.

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