Patent ID: 11870992
Assignee: PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 1:
2. A decoder comprising:
a processor; and
memory,
wherein, using the memory, the processor:
determines an intra prediction mode used for a current block;
determines an inverse primary transform basis used for an inverse primary transform;
performs an inverse quantization on quantized coefficient of the current block to generate second transform coefficients;
when the inverse primary transform basis is different from predetermined inverse transform bases, performs the inverse primary transform on the second transform coefficients using the inverse primary transform basis without performing an inverse secondary transform, to generate a residual signal of the current block; and
when the inverse primary transform basis is included in the predetermined inverse transform bases, (i) performs an inverse secondary transform on the second transform coefficients, using an inverse secondary transform basis selected from among one or more candidate inverse secondary transform bases associated with the intra prediction mode, to generate first transform coefficients and (ii) performs the inverse primary transform on the first transform coefficients, using the inverse primary transform basis, to generate a residual signal of the current block, and

wherein the inverse secondary transform is performed on a part of the second transform coefficients generated by the inverse quantization.