Texas Instruments Incorporated
Low complexity large transform

Abstract:

Methods of encoding a video stream in a video encoder and decoding an encoded video stream in a video decoder using a low complexity large transform are provided. An encoding method includes receiving an n.times.n residual block in a transform component of the video encoder, and transforming the n.times.n residual block using an n.times.n transform to generate an n.times.n transform coefficient block, wherein the n.times.n transform is based on (n/m*n/m) m.times.m Hadamard transforms and (m*m) (n/m).times.(n/m) discrete cosign transforms, wherein m<n. A decoding method includes receiving an n.times.n transform coefficient block in an inverse transform component of the video decoder, and applying an n.times.n inverse transform to the n.times.n transform coefficient block to reconstruct an n.times.n residual block, wherein the n.times.n inverse transform is based on (n/m*n/m) m.times.m Hadamard transforms and (m*m) (n/m).times.(n/m) inverse discrete cosign transforms, wherein m<n.