Dictionary of transforms

An apparatus for decoding a current block of a current frame in a coded video bitstream, the apparatus comprising:

• a memory storing instructions;
• and
• a processor in communication with the memory, wherein, when the processor executes the instructions, the processor is configured to cause the apparatus to:
• receive the coded video bitstream;
• determine, based on the coded video bitstream, a transform pile for the current block, the transform pile being one transform pile in a transform dictionary, the transform dictionary comprising a plurality of transform piles, and the transform pile comprising a plurality of transform sets;
• determine a transform set in the transform pile;
• determine a transform kernel in the transform set;
• perform an inverse transform for the current block based on the transform kernel for obtaining a residual block for the current block;
• and
• reconstruct the current block based on the residual block.

A non-transitory computer readable storage medium storing instructions, wherein, when the instructions are executed by a processor, the instructions are configured to cause the processor to:

• receive the coded video bitstream;
• determine, based on the coded video bitstream, a transform pile for the current block, the transform pile being one transform pile in a transform dictionary, the transform dictionary comprising a plurality of transform piles, and the transform pile comprising a plurality of transform sets;
• determine a transform set in the transform pile;
• determine a transform kernel in the transform set;
• perform an inverse transform for the current block based on the transform kernel for obtaining a residual block for the current block;
• and
• reconstruct the current block based on the residual block.