Decoding apparatus and method, encoding apparatus and method, and program

摘要

The present invention relates to a decoding apparatus, a decoding method, an encoding apparatus, an encoding method, and programs that can shorten the delay time caused by the band extension at the time of decoding, and restrain increases in resources on the decoding side.;A higher frequency component generating unit (73) generates a pseudo higher frequency spectrum by using a lower frequency spectrum (SP-L) and a higher frequency envelope (ENV-H). A phase randomizing unit (74) randomizes the phase of the pseudo higher frequency spectrum, based on a random flag (RND). An inverse MDCT unit (75) denormalizes the lower frequency spectrum (SP-L) by using a lower frequency envelope (ENV-L), and combines the pseudo higher frequency spectrum supplied from the phase randomizing unit (74) with the denormalized lower frequency spectrum (SP-L). The combination result is used as the spectrum of the entire band. The present invention can be applied to a decoding apparatus that performs band extension decoding, for example.

主权项

1. A decoding apparatus comprising:
an obtaining unit configured to obtain, as encoding results, a lower frequency envelope of an audio signal, a lower frequency spectrum normalized by using the lower frequency envelope, a higher frequency envelope of the audio signal, and a degree of concentration of a higher frequency spectrum of the audio signal; a generating unit configured to generate a spectrum by using the normalized lower frequency spectrum and the higher frequency envelope in the encoding results obtained by the obtaining unit; a randomizing unit configured to randomize a phase of the spectrum, based on the degree of concentration, the spectrum being generated by the generating unit; and a combining unit configured to denormalize the lower frequency spectrum by using the lower frequency envelope in the encoding results obtained by the obtaining unit, and combine the spectrum randomized by the randomizing unit or the spectrum generated by the generating unit with the denormalized lower frequency spectrum, a result of the combination being used as a spectrum of an entire band.