Harmonic Vector Excitation Coding
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 was published as subpart 2 of ISO/IEC 14496-3:1999 (MPEG-4 Audio) in 1999.[1] An extended version of HVXC was published in MPEG-4 Audio Version 2 (ISO/IEC 14496-3:1999/Amd 1:2000).[2][3]
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.[4]
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.[4][5]
References
- ^ ISO (1999). "ISO/IEC 14496-3:1999 - Information technology -- Coding of audio-visual objects -- Part 3: Audio". ISO. Retrieved 2009-10-09.
- ^ ISO (2000). "ISO/IEC 14496-3:1999/Amd 1:2000 - Audio extensions". ISO. Retrieved 2009-10-07.
- ^ ISO/IEC JTC 1/SC 29/WG 11 (1999-07), ISO/IEC 14496-3:/Amd.1 - Final Commitee 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) - ^ 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) - ^ Masayuki Nishiguchi (2006-04-17), Harmonic vector excitation coding of speech (PDF), Acoustical Science and Technology, retrieved 2009-10-09
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