Patent ID: 11922956
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 10:
11. A non-transitory digital storage medium having a computer program stored thereon to perform, when the computer program is run by a computer, the method of decoding an encoded audio signal, the method comprising:
generating a first decoded representation of a first set of first spectral portions, the first decoded representation comprising a first spectral resolution;
generating a second decoded representation of a second set of second spectral portions, the second decoded representation comprising spectral envelope information comprising a second spectral resolution being lower than the first spectral resolution;
regenerating a reconstructed second spectral portion comprising the first spectral resolution using a first spectral portion of the first set of first spectral portions and the spectral envelope information for a second spectral portion of the second set of second spectral portions; and
converting the first decoded representation and the reconstructed second spectral portion into a time representation,
wherein a first encoded representation of the first set of first spectral portions comprises encoded spectral lines in the first set of first spectral portions and scale factors for each scale factor band in a core range below an intelligent gap filling start frequency and for each scale factor band in a reconstruction band above the intelligent gap filling start frequency until a maximum frequency, the maximum frequency being smaller than or equal to a half of a sampling frequency of an audio signal, or
wherein the spectral envelope information for the second set of second spectral portions corresponds to energy information values for scale factor bands above the intelligent gap filling start frequency, wherein each energy information value represents a single spectral value per scale factor band above the intelligent gap filling start frequency until a maximum frequency, or
wherein the generating the first decoded representation spectral domain audio decoder comprises generating the first decoded representation so that a first spectral portion of the first set of first spectral portions is placed, with respect to frequency, between two second spectral portions of the second set of second spectral portions, and wherein the first spectral portion of the first set of first spectral portions and at least one of the two second spectral portions of the second set of second spectral portions belong to a scale factor band in a reconstruction band above the intelligent gap filling start frequency, or
wherein the reconstructed second spectral portion comprises the scale factor bands in a reconstruction band above the intelligent gap filling start frequency, wherein the regenerating the reconstructed second spectral portion comprises performing a tile filling operation using a source band identification for identifying the first spectral portion of the first set of first spectral portions and a target band identification identifying a target band to generate a raw second portion of spectral lines comprising the first spectral resolution; calculating a gain factor using an analysis of a source band identified by the source band identification or the raw second portion and an analysis of the first spectral portion of the first set of first spectral portions in a reconstruction band; and adjusting an energy of the raw second portion so that an energy of a scale factor band in the reconstruction band in an adjusted frame comprises an energy as indicated by the energy information value for the corresponding scale factor band, wherein the first spectral portion of the first set of first spectral portions in the reconstruction band in the adjusted frame is not influenced by the adjusting, or
wherein the regenerating the reconstructed second spectral portion comprises determining a survive energy information comprising an accumulated energy of the first spectral portion of the first set of first spectral portions in the specific scale factor band; determining a tile energy information of the two second spectral portions of the second set of second spectral portions belonging to the specific scale factor band, wherein the two second spectral portions of the second set of second spectral portions belonging to the specific scale factor band are to be generated by frequency regeneration using a first source spectral portion different from the first spectral portion in the specific scale factor band; calculating a missing energy in the specific scale factor band using an energy information value for the specific scale factor band and the survive energy information; and adjusting the two second spectral portions of the second set of second spectral portions belonging to the specific scale factor band based on the missing energy information and the tile energy information to acquire the reconstructed second spectral portion comprising the first spectral resolution, wherein the first spectral portion of the first set of first spectral portions in the specific scale factor band is not influenced by the adjusting, or
wherein the method comprises inverse scaling dequantized spectral values corresponding to first spectral portions of the first set of spectral portions using the scale factors for the scale factor bands to provide the first spectral portions below the frequency gap filling start frequency and the first spectral portions above the frequency gap filling start frequency in a reconstruction band, and wherein a spectral envelope adjusting of the regenerating comprises receiving a first source spectral portion used for frequency tile filling in the reconstruction band, wherein adjusted spectral values for the second spectral portions in the reconstruction band acquired by the spectral envelope adjusting and the first spectral portion in the reconstruction band jointly represent a spectral representation of the reconstruction band.