Patent ID: 11887611
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A parametric frequency-domain audio decoder, comprising a microprocessor or electronic circuit configured to,
decode, using entropy decoding, from a data stream
a first spectrum of a first channel of a current frame of a multichannel audio signal, wherein the first spectrum is subdivided into scale factor bands, and
for each scale factor band, a scale factor associated with the respective scale factor band,

check, for a predetermined scale factor band, whether all spectral lines of the first spectrum within the predetermined scale factor band are zero,
if all spectral lines within the predetermined scale factor band are zero, fill the first spectrum within the predetermined scale factor band with noise determined from spectral lines of
a previous frame of the multichannel audio signal, or
a second channel of the current frame of the multichannel audio signal, to obtain a second spectrum;

scale the second spectrum within each scale factor band, including the predetermined scale factor band, using the scale factor of the respective scale factor band to obtain a third spectrum; and
subject the third spectrum to an inverse transform so as to acquire a time domain portion of the first channel of the multichannel audio signal.