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

Claim 0:
1. An encoder comprising:
a processor; and
memory,
wherein, using the memory, the processor:
derives a residual signal of a current block by subtracting a prediction signal from an input signal;
determines an intra prediction mode used for the current block;
performs a primary transform on the residual signal, using a primary transform basis, to generate first transform coefficients;
when the primary transform basis is different from predetermined transform bases, performs a quantization on the first transform coefficients without performing a secondary transform; and
when the primary transform basis is included in the predetermined transform bases, (i) performs a secondary transform on the first transform coefficients, using a secondary transform basis selected from among one or more candidate secondary transform bases associated with the intra prediction mode, to generate second transform coefficients, and (ii) performs a quantization on the second transform coefficients, and

wherein the secondary transform is performed on a part of the first transform coefficients generated by the primary transform.