1. A frequency envelope vector quantization method, comprising: dividing N frequency envelopes in a frame into N1 vectors, wherein each vector in the N1 vectors comprises M frequency envelopes, and wherein N1, N, and M are positive integers, M is greater than or equal to 2, and N is greater than N1; quantizing a first vector in the N1 vectors by using a first codebook that has B bits, to obtain a code word corresponding to the quantized first vector, wherein the first codebook is divided into 2 B1 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, according to the code word corresponding to the quantized first vector, whether the quantized first vector is associated with the i th portion in the 2 B1 portions of the first codebook, wherein i is a positive integer greater than or equal to 1 and less than or equal to 2 B1 ; based on a determination that the quantized first vector is associated with the i th portion in the 2 B1 portions of the first codebook, determining a second codebook according to the codebook of the i th portion of the first codebook; and quantizing a second vector in the N1 vectors based on the second codebook.