CPC G10L 19/002 (2013.01) [G10L 19/02 (2013.01); G10L 19/0204 (2013.01); G10L 21/038 (2013.01)] | 12 Claims |
1. A method for encoding an audio signal, the method comprising:
generating an envelope of a low band of a spectrum based on a sub-band configuration of a full band, and quantizing the envelope of the low band;
generating an envelope of a high band of the spectrum based on a sub-band configuration of the high band and quantizing the envelope of the high band;
generating a mapped envelope of the high band by mapping the envelope of the high band into a sub-band configuration of the full band, and quantizing the mapped envelope;
generating an envelope of the full band by combining the quantized mapped envelope of the high band with the quantized envelope of the low band;
determining to perform envelope refinement if there is any sub-band to which a bit is allocated in the high band based on bit allocation information of the envelope of the full band; and
in response to determining to perform the envelope refinement, calculating a delta of norm which is a difference between the mapped envelope and an envelope from an original spectrum for the sub-band to which the bit is allocated in the high band, and generating a bitstream including the delta of norm.
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