Patent ID: 11922957
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 16:
17. An audio decoder for decoding an encoded audio signal, the audio decoder comprising a decoder for decoding an encoded downmix matrix for obtaining a decoded downmix matrix, the decoded downmix matrix, mapping a plurality of input channels of an audio content to a plurality of output channels, the input and output channels being associated with respective speakers at predetermined positions relative to a listener position, wherein a downmix matrix is encoded to obtain the encoded downmix matrix by exploiting a symmetry of speaker pairs of the plurality of input channels and a symmetry of speaker pairs of the plurality of output channels, the decoder comprising:
a processor configured to receive encoded information representing the encoded downmix matrix, and to decode the encoded information,
wherein respective pairs of input and output channels in the downmix matrix have associated respective mixing gains for adapting a level by which a given input channel contributes to a given output channel, and
wherein, for decoding the encoded downmix matrix, the processor is further configured to
decode encoded significance values from the encoded information representing the encoded downmix matrix for obtaining decoded significance values, wherein respective decoded significance values are assigned to pairs of symmetric speaker groups of the input channels and symmetric speaker groups of the output channels, wherein a decoded significance value indicates if a mixing gain for one or more of the input channels is zero or not; and
decode encoded mixing gains from the encoded information representing the encoded downmix matrix for obtaining the mixing gains, and
wherein decoding the encoded significance values is based on a template, the template having the same pairs of speaker groups of the input channels and speaker groups of the output channels as the downmix matrix, wherein respective template significance values are assigned to pairs of symmetric speaker groups of the input channels and symmetric speaker groups of the output channels of the template.