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Harmonic Vector Excitation Coding

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Harmonic Vector Excitation Coding, abbreviated as HVXC is a speech coding algorithm used in MPEG-4 Part 3 (MPEG-4 Audio) standard for very low bit rate speech coding. HVXC supports bit rates of 2 and 4 kbit/s in the fixed and variable bit rate mode and sampling frequency 8 kHz. It also operates at lower bitrates, such as 1.2 - 1.7 kbit/s, using a variable bit rate technique.[1] The total algorithmic delay for the encoder and decoder is 36 ms.[2]

It was published as subpart 2 of ISO/IEC 14496-3:1999 (MPEG-4 Audio) in 1999.[3] An extended version of HVXC was published in MPEG-4 Audio Version 2 (ISO/IEC 14496-3:1999/Amd 1:2000).[4][5]

MPEG-4 Natural Speech Coding Tool Set uses two algorithms: HVXC and CELP (Code Excited Linear Prediction). HVXC is used at a low bit rate of 2 or 4 kbit/s. Higher bitrates than 4 kbit/s in addition to 3.85 kbit/s are covered by CELP.[6]

Technology

HVXC is a parametric speech codec, which in practice means that it is optimized for speech signals only. HVXC consists of LSP (line spectral pair) VQ (vector quantization) tool and harmonic VQ tool.[2][6]

References

  1. ^ ISO/IEC (2009-09-01), ISO/IEC 14496-3:2009 - Information technology -- Coding of audio-visual objects -- Part 3: Audio (PDF), IEC, retrieved 2009-10-07
  2. ^ a b Masayuki Nishiguchi (2006-04-17), Harmonic vector excitation coding of speech (PDF), Acoustical Science and Technology, retrieved 2009-10-09
  3. ^ ISO (1999). "ISO/IEC 14496-3:1999 - Information technology -- Coding of audio-visual objects -- Part 3: Audio". ISO. Retrieved 2009-10-09.
  4. ^ ISO (2000). "ISO/IEC 14496-3:1999/Amd 1:2000 - Audio extensions". ISO. Retrieved 2009-10-07.
  5. ^ ISO/IEC JTC 1/SC 29/WG 11 (1999-07), ISO/IEC 14496-3:/Amd.1 - Final Committee Draft - MPEG-4 Audio Version 2 (PDF), retrieved 2009-10-07 {{citation}}: Check date values in: |date= (help)CS1 maint: numeric names: authors list (link)
  6. ^ a b Karlheinz Brandenburg, Oliver Kunz, Akihiko Sugiyama. "MPEG-4 Natural Audio Coding - Natural Speech Coding Tools". Retrieved 2009-10-09.{{cite web}}: CS1 maint: multiple names: authors list (link)
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