Efficient encoding/decoding of audio signals

摘要

A method for encoding of an audio signal comprises performing (214) of a transform of the audio signal. An energy offset is selected (216) for each of the first subbands. An energy measure of a first reference band within a low band of an encoding of a synthesis signal is obtained (212). The first high band is encoded (220) by providing quantization indices representing a respective scalar quantization of a spectrum envelope in the first subbands of the first high band relative to the energy measure of the first reference band by use of the selected energy offset. An encoder apparatus comprises means for carrying out the steps of the method. Corresponding decoder methods and apparatuses are also described.

主权项

1. A method, in an audio encoding device, for encoding of an audio signal, the method comprising:
obtaining a low band synthesis signal of an encoding of said audio signal; obtaining a first energy measure of a first reference band within a low band (LB) in said low band synthesis signal; performing a transform of said audio signal into a transform domain; selecting an energy offset from a set of at least two predetermined energy offsets for each of a plurality of first subbands of a first high band (HB-1) of said audio signal in said transform domain, said first high band (HB-1) being situated at higher frequencies than said low band (LB); and encoding said first high band (HB-1), wherein said encoding of said first high band (HB-1) comprises providing a first set of quantization indices representing a respective scalar quantization of a spectrum envelope in said plurality of first subbands of said first high band (HB-1) relative to said first energy measure, said first set of quantization indices being given with a respective said selected energy offset, and wherein said encoding of said first high band (HB-1) further comprises providing a parameter defining the used energy offset; obtaining a second energy measure of a second reference band within said low band (LB) in said low band synthesis signal; and encoding a second high band (HB-2) of said audio signal in said transform domain, said second high band (HB-2) being situated in frequency between said low band (LB) and said first high band (HB-1), and wherein said encoding of said second high band (HB-2) comprises providing a second set of quantization indices representing a respective scalar quantization of a spectrum envelope in a plurality of second subbands of said second high band (HB-2) relative to said second energy measure.