Harmonic Vector Excitation Coding

from Wikipedia, the free encyclopedia

Harmonic Vector Excitation Coding ( HVXC ) is on the transfer of language optimized process for compression of audio data . Despite very low bit rates , HVXC-coded data are suitable for the transmission of speech in an acceptable quality. It is used in digital broadcasting , for satellite communication and internet telephony as well as for voice databases . This procedure is part of the MPEG-4 standard and is described in ISO / IEC 14496-3.

technology

HVXC is a two-tier codec . In the first step, the output signal is compressed with linear predictive coding . The result is decoded and compared with the output signal. The resulting residues (differences between the output signal and the decoded signal) are then compressed again with Parametric Audio Coding . At HVXC, however , this algorithm is only used for voiced speech; other signals are compressed using Code Excited Linear Prediction .

HVXC is optimized for voice transmission at variable bit rates below 2 kbit / s and fixed bit rates of 2 kbit / s and 4 kbit / s. It works with a sampling frequency of 8 kHz, a frequency band of 300–3400 Hz and an algorithmic delay of 33.5–56 ms.

literature

  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich et al. 2006, ISBN 3-446-40198-9 .

Web links