LOW COMPLEXITY LARGE TRANSFORM

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×n residual block in a transform component of the video encoder, and transforming the n×n residual block using an n×n transform to generate an n×n transform coefficient block, wherein the n×n transform is based on (n/m*n/m) m×m Hadamard transforms and (m*m) (n/m)×(n/m) discrete cosign transforms, wherein m<n. A decoding method includes receiving an n×n transform coefficient block in an inverse transform component of the video decoder, and applying an n×n inverse transform to the n×n transform coefficient block to reconstruct an n×n residual block, wherein the n×n inverse transform is based on (n/m*n/m) m×m Hadamard transforms and (m*m) (n/m)×(n/m) inverse discrete cosign transforms, wherein m<n.