Harmonic Vector Excitation Coding

From Wikipedia, the free encyclopedia

  (Redirected from HVXC)
Jump to: navigation, search

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]

[edit] Technology

HVXC is a parametric speech codec, which in practise 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]

[edit] References

  1. ^ ISO/IEC (2009-09-01) (PDF), ISO/IEC 14496-3:2009 - Information technology -- Coding of audio-visual objects -- Part 3: Audio, IEC, http://webstore.iec.ch/preview/info_isoiec14496-3%7Bed4.0%7Den.pdf, retrieved 2009-10-07 
  2. ^ a b Masayuki Nishiguchi (2006-04-17) (PDF), Harmonic vector excitation coding of speech, Acoustical Science and Technology, http://www.jstage.jst.go.jp/article/ast/27/6/375/_pdf, retrieved 2009-10-09 
  3. ^ ISO (1999). "ISO/IEC 14496-3:1999 - Information technology -- Coding of audio-visual objects -- Part 3: Audio". ISO. http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=25035. Retrieved 2009-10-09. 
  4. ^ ISO (2000). "ISO/IEC 14496-3:1999/Amd 1:2000 - Audio extensions". ISO. http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=31568. Retrieved 2009-10-07. 
  5. ^ ISO/IEC JTC 1/SC 29/WG 11 (1999-07) (PDF), ISO/IEC 14496-3:/Amd.1 - Final Commitee Draft - MPEG-4 Audio Version 2, ftp://ftp.tnt.uni-hannover.de/pub/MPEG/audio/mpeg4/documents/w2803/w2803_n.pdf, retrieved 2009-10-07 
  6. ^ a b Karlheinz Brandenburg, Oliver Kunz, Akihiko Sugiyama. "MPEG-4 Natural Audio Coding - Natural Speech Coding Tools". http://www.chiariglione.org/mpeg/tutorials/papers/icj-mpeg4-si/09-natural_audio_paper/speechtools.html. Retrieved 2009-10-09. 


Stub icon This computer-related article is a stub. You can help Wikipedia by expanding it.
Retrieved from "http://en.wikipedia.org/wiki/Harmonic_Vector_Excitation_Coding"
Languages