Support of a multichannel audio extension
AssigneeNokia Corporation
InventorJuha Ojanpera
Life of this patent
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Abstract
The invention relates to methods and units supporting a multichannel audio extension. In order to allow an efficient extension requiring a low computational complexity, it is proposed that at an encoding end, at least state information is provided as side information for a provided mono audio signal (M) generated out of a multichannel audio signal. The state information indicates for each of a plurality of frequency bands how a predetermined or equally provided gain value is to be applied in the frequency domain to the mono audio signal (M) for obtaining first and a second channel signals (L,R) of a reconstructed multichannel audio signal.
Claims41
A method for supporting a multichannel audio extension at an encoding end of a multichannel audio coding system, said method comprising:
- transforming a first channel signal (L) of a multichannel audio signal into the frequency domain, resulting in a spectral first channel signal (LMDCT);
- transforming a second channel signal (R) of said multichannel audio signal into the frequency domain, resulting in a spectral second channel signal (RMDCT);
- and
- determining for each of a plurality of adjacent frequency bands whether said spectral first channel signal (LMDCT), said spectral second channel signal (RMDCT) or none of said spectral channel signals (LMDCT,RMDCT) is dominant in the respective frequency band and providing a corresponding state information for each of said frequency bands.
A method for supporting a multichannel audio extension at a decoding end of a multichannel audio coding system, said method comprising:
- transforming a received mono audio signal (M) into the frequency domain, resulting in a spectral mono audio signal;
- and
- generating a spectral first channel signal (LMDCT, {tilde over (L)}f) and a spectral second channel signal (RMDCT, {tilde over (R)}f) out of said spectral mono audio signal by weighting said spectral mono audio signal separately in each of a plurality of adjacent frequency bands for each of said spectral first channel signal (LMDCT, {tilde over (L)}f) and said spectral second channel signal (RMDCT, {tilde over (R)}f) based on at least one gain value and in accordance with a received state information, said state information indicating for each of said frequency bands whether said spectral first channel signal (LMDCT, {tilde over (L)}f), said spectral second channel signal (RMDCT, {tilde over (R)}f) or none of said spectral channel signals (LMDCT, {tilde over (L)}f,RMDCT, {tilde over (R)}f) is to be dominant within the respective frequency band.
Dependencies are inferred from the claim text.