Transform and quantization architecture for video coding and decoding

摘要

A method of encoding a video stream in a video encoder is provided that includes computing an offset into a transform matrix based on a transform block size, wherein a size of the transform matrix is larger than the transform block size, and wherein the transform matrix is one selected from a group consisting of a DCT transform matrix and an IDCT transform matrix, and transforming a residual block to generate a DCT coefficient block, wherein the offset is used to select elements of rows and columns of a DCT submatrix of the transform block size from the transform matrix.

主权项

1. A method of encoding a video stream, comprising:
providing a transform matrix having a size M×M; providing a residual block having a size P×P; computing an offset into the transform matrix based on the size of the residual block when P is less than M; transforming the residual block to generate a DCT coefficient block using elements of the transform matrix selected by the offset; providing a quantization step size for the DCT coefficient block; and quantizing each non-zero coefficient in the DCT coefficient block using the quantization step size.