INTERACTION BETWEEN CORE TRANSFORM AND SECONDARY TRANSFORM

• Main Authors: HSU, Chih-Wei, CHIANG, Man-Shu
• Format: Patent
• Language: English; French; German
• Published: 03.05.2023
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

A video decoder receives data from a bitstream for a block of pixels to be decoded as a current block of a current picture of a video. The video decoder receives from the bitstream a first signaled index and a second signaled index for the current block. The video decoder determines a first merge index and a second merge index from the first and second signaled indices. The video decoder uses the first merge index to select a first motion candidate and the second merge index to select a second motion candidate. A video decoder generates a set of prediction samples in ALWIP mode and performs an inverse secondary transform and then an inverse primary transform to generate a set of residual samples of the current block. Enabling or selection of secondary transform and/or primary transform depends on size, width, height or combination of the above for the current block. The video decoder reconstructs the current block by using the set of residual samples and the set of prediction samples.