APPARATUS AND METHOD FOR ENCODING VIDEO USING DIFFERENT SECOND-STAGE TRANSFORM

A system, apparatus, and method of encoding a video stream having a plurality of frames, each frame having a plurality of blocks is disclosed. The method includes selecting a group of blocks from a current frame of the plurality of frames, determining a plurality of first stage transform coefficient matrices for the group of blocks using a first transform technique, determining a DC second stage transform coefficient matrix for the group of blocks based on at least some of the plurality of first stage transform coefficient matrices and using a second transform technique on a processor, and encoding the group of blocks into an encoding format using the DC second stage coefficient matrix and the first stage coefficient matrices.