Vector quantizer

摘要

Vector Quantizer and method therein for efficient vector quantization, e.g. in a transform audio codec. The method comprises comparing an input target vector s with a plurality of centroids, each centroid representing a respective class of codevectors in a codebook. Further, a starting point for a search related to the input target vector in the codebook is determined, based on the result of the comparison. The codevectors in the codebook are sorted according to a distortion measure reflecting the distance between each codevector and the centroids of the classes. The Vector Quantizer and method enables that the class of codevectors comprising the most probable candidate codevectors in regard of the input vector. s may be searched first.

主权项

1. A method in a Vector Quantizer, the method comprising:
comparing an input target vector representing a spectral region of a segment of an audio signal with a plurality of centroids, each centroid representing a respective class of codevectors in a codebook, determining a starting point for a search related to the input target vector in the codebook, based on the a result of the comparing the input target vector with the plurality of centroids, performing a search in the codebook, starting at the determined starting point, and identifying a codevector to represent the input target vector, wherein the search is performed in one class of codevectors in the codebook that is selected based on the result of the comparing the input target vector with the plurality of centroids, generating, using the codevector that is identified, a coded spectral region representation of the input target vector representing the spectral region of the segment of the audio signal, and transmitting, through a communication circuit, the coded spectral region representation of the input target vector representing the spectral region of the segment of the audio signal, wherein the codevectors in the codebook are sorted according to a distortion measure reflecting a distance between each codevector among the codevectors in the codebook and the centroids.