| 摘要 |
There is disclosed an encoder apparatus whereby the decoded-signal quality can be improved in a hierarchical encoding (scalable encoding) system in which a band to be encoded is selected for each of a plurality of layers. The encoder apparatus (101) comprises: a first layer encoder unit (202) that selects a first band of an input spectrum, which is to be quantized, from among a plurality of sub-bands to which a frequency range has been divided and that generates first layer encoded information including first band information of the selected band; an adder unit (204) that uses both a first decoded signal, which has been generated by use of the first layer encoded information, and the input spectrum to generate a first layer differential spectrum; and a second layer encoder unit (205) that selects a second band of the first layer differential spectrum, which is to be quantized, and that generates second layer encoded information including second band information of the selected band. Based on the first and second band information, the first layer encoder unit (202) decides, from a plurality of candidates, a method for quantizing the gain of the input spectrum. |
