Vector quantization

Abstract

It is inter alia disclosed to determine a first quantized representation of an input vector, and to determine a second quantized representation of the input vector based on a codebook depending on the first quantized representation

1 - 61 . (canceled) 
     
     
         62 . A method comprising:
 determining a first quantized representation of an input vector; and   determining a second quantized representation of the input vector based on a codebook depending on the first quantized representation.   
     
     
         63 . The method according to  claim 62 , wherein said determining a second quantized representation of the input vector comprises selecting a codebook of a plurality of codebooks based on the first quantized representation. 
     
     
         64 . The method according to  claim 62 , comprising, prior to determining the second quantized representation of the input vector, normalizing the input vector based on the first quantized representation. 
     
     
         65 . The method according to  claim 64 , wherein said input vector comprises a plurality of vector components, and wherein said normalizing comprises multiplying at least one vector component of the input vector with a respective normalization coefficient depending on the first quantized representation. 
     
     
         66 . The method according to  claim 65 , comprising selecting a set of normalization coefficients of a plurality of sets of normalization coefficients based on the first quantized representation, wherein the respective normalization coefficient to be multiplied with one of the at least one vector component of the input vector is from the selected set of normalization coefficients. 
     
     
         67 . The method according to  claim 62 , wherein a codebook is defined by an associated set of basis codevectors and an associated at least one scale representative, wherein a codevector of the codebook is defined by a basis codevector of the associated set of basis codevectors scaled by a scale representative of the associated at least one scale representative. 
     
     
         68 . The method according to  claim 62 , wherein said input vector at least partially represents at least one of a video, image, audio and speech signal. 
     
     
         69 . An apparatus, comprising at least one processor; and at least one memory including computer program code, said at least one memory and said computer program code configured to, with said at least one processor, cause said apparatus at least to:
 determine a first quantized representation of an input vector; and   determinie a second quantized representation of the input vector based on a codebook depending on the first quantized representation.   
     
     
         70 . The apparatus according to  claim 69 , wherein the apparatus caused to determine a second quantized representation of the input vector is further caused to select a codebook of a plurality of codebooks based on the first quantized representation. 
     
     
         71 . The apparatus according to  claim 69 , wherein said at least one memory and said computer program code is configured to, with said at least one processor, cause said apparatus further to prior to being caused to determine the second quantized representation of the input vector, to normalize the input vector based on the first quantized representation. 
     
     
         72 . The apparatus according to  claim 71 , wherein said input vector comprises a plurality of vector components, and wherein said apparatus caused to normalize is further caused to multiply at least one vector component of the input vector with a respective normalization coefficient depending on the first quantized representation. 
     
     
         73 . The apparatus according to  claim 72 , wherein said at least one memory and said computer program code is configured to, with said at least one processor, cause said apparatus further to select a set of normalization coefficients of a plurality of sets of normalization coefficients based on the first quantized representation, wherein the respective normalization coefficient to be multiplied with one of the at least one vector component of the input vector is from the selected set of normalization coefficients. 
     
     
         74 . The apparatus according to  claim 69 , wherein a codebook is defined by an associated set of basis codevectors and an associated at least one scale representative, wherein a codevector of the codebook is defined by a basis codevector of the associated set of basis codevectors scaled by a scale representative of the associated at least one scale representative. 
     
     
         75 . The apparatus according to  claim 69 , wherein said input vector at least partially represents at least one of a video, image, audio and speech signal. 
     
     
         76 . A method, comprising:
 selecting a codebook of a plurality of codebooks based on a first quantized representation of an vector; and   dequantizing a second quantized representation of the vector based on the selected codebook.   
     
     
         77 . The method according to  claim 76 , further comprising determining a normalization representation based on the first quantized representation of the vector and reversing a normalization of the vector based on the normalization representation. 
     
     
         78 . An apparatus, comprising at least one processor; and at least one memory including computer program code, said at least one memory and said computer program code configured to, with said at least one processor, cause said apparatus at least to:
 select a codebook of a plurality of codebooks based on a first quantized representation of an vector; and   dequantize a second quantized representation of the vector based on the selected codebook.   
     
     
         79 . The apparatus as claimed in  claim 78 , where in the apparatus is further caused to determine a normalization representation based on the first quantized representation of the vector and reverse a normalization of the vector based on the normalization representation.