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Frequency envelope vector quantization method and apparatus

  • US 9,805,732 B2
  • Filed: 12/29/2015
  • Issued: 10/31/2017
  • Est. Priority Date: 07/04/2013
  • Status: Active Grant
First Claim
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1. A method of quantizing frequency envelops of an audio signal, for use by an audio signal encoder, comprising:

  • obtaining N frequency envelopes of a frame of the audio signal, wherein N is a positive integer;

    organizing the N frequency envelopes into N1 groups, wherein each group comprises M frequency envelopes, and wherein N1 and M are positive integers, M is greater than or equal to 2, and N is greater than N1;

    quantizing a first group of frequency envelopes to obtain a first vector by using a first codebook wherein the first codebook has 2B code words and each code word corresponds to a vector, wherein the first codebook is divided into 2B1 portions, and wherein B is a positive integer greater than or equal to 2, and B1 is a positive integer greater than or equal to 1;

    determining that a code word corresponding to the first vector is in the ith portion of the first codebook, wherein i is a positive integer greater than or equal to 1 and less than or equal to 2B1;

    determining a second codebook according to the ith portion of the first codebook; and

    quantizing a second group of frequency envelopes by using the second codebook.

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