Abstract: Provided are a voice audio encoding device, voice audio decoding device, voice audio encoding method, and voice audio decoding method that efficiently perform bit distribution and improve sound quality. Dominant frequency band identification unit identifies a dominant frequency band having a norm factor value that is the maximum value within the spectrum of an input voice audio signal. Dominant group determination units and non-dominant group determination unit group all sub-bands into a dominant group that contains the dominant frequency band and a non-dominant group that contains no dominant frequency band. Group bit distribution unit distributes bits to each group on the basis of the energy and norm variance of each group. Sub-band bit distribution unit redistributes the bits that have been distributed to each group to each sub-band in accordance with the ratio of the norm to the energy of the groups.

Abstract: An apparatus for decoding a surround audio signal includes a Bitstream De-multiplexer for unpacking a bitstream into spatial parameters and core parameters, a set of core decoders for decoding the core parameters into a set of core signals, a matrix derivation unit for deriving the rendering matrix from the spatial parameters and playback speaker layout information, and a renderer for rendering of the decoded core signals to playback signals using the rendering matrix.

Abstract: An audio signal decoding apparatus is provided that includes a receiver that receives an encoded information, a memory, and a processor that demultiplexes the encoded information, including encoding parameters that are used for decoding a low frequency spectrum and index information that identifies a most, correlated portion from a low frequency spectrum for one or more high frequency subbands. The processor also replicates a high frequency subband spectrum based on the index information using a synthesized low frequency spectrum, the synthesized low frequency spectrum being obtained by decoding the encoding parameters. The processor further estimates a frequency of a harmonic component in the synthesized low frequency spectrum, adjusts a frequency of a harmonic component in the high frequency subband spectrum using the estimated harmonic frequency, and generates an output signal using the synthesized low frequency spectrum and the high frequency subband spectrum.

Abstract: An audio/speech encoding method is provided that includes transforming a time domain input signal to a frequency spectrum, and dividing the frequency spectrum to a plural of bands. The method also includes calculating a level of energies for each band, quantizing the energies for the each band, and calculating differential indices. The method additionally includes modifying a range of the differential indices for the Nth band when N is an integer of 2 or more, and replacing the differential index with the modified differential index, and not modifying a range of the differential indices for the Nth band when N is an integer of 1. The method further includes encoding the differential indices using a Huffman table selected based on a minimum value and a maximum value of the differential indices, and transmitting the encoded differential indices and a flag signal for indicating the selected Huffman table.

Abstract: An audio/speech encoding method is provided that includes transforming a time domain input signal to a frequency spectrum, and dividing the frequency spectrum to a plural of bands. The method also includes calculating a level of energies for each band, quantizing the energies for the each band, and calculating differential indices. The method additionally includes modifying a range of the differential indices for the Nth band when N is an integer of 2 or more, and replacing the differential index with the modified differential index, and not modifying a range of the differential indices for the Nth band when N is an integer of 1. The method further includes encoding the differential indices using a Huffman table selected based on a minimum value and a maximum value of the differential indices, and transmitting the encoded differential indices and a flag signal for indicating the selected Huffman table.