Vector-space methods for primary-ambient decomposition of stereo audio signals
AssigneeCreative Technology Ltd
InventorMichael M. Goodwin
Life of this patent
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Abstract
An audio signal is processed to determine primary and ambient components by transforming the signal into frequency-domain vectors, and decomposing the left and right channel vectors into ambient and primary components by orthogonal projection.
Claims15
A method for processing a multichannel audio signal to determine primary and ambient components of the signal, the method comprising:
- converting each channel of the multichannel audio signal to corresponding subband vectors, wherein the vectors comprise a time sequence or history of the channel signal's behavior in corresponding subbands;
- determining a primary component unit vector for each subband by a principal component analysis;
- and
- determining primary component vectors for each audio channel in each subband by projecting the channel subband vector onto the primary component unit vector;
- and
- determining the ambience component vector for each channel in each frequency subband as the projection residual.
A method for processing a stereo audio signal to derive primary and ambient components of the signal, comprising:
- converting left and right channels of the audio signal to corresponding frequency-domain vectors, each vector comprising a time sequence or history of the signal behavior in corresponding subbands;
- using principal component analysis to provide multichannel signal content, wherein each channel is modeled as the sum of a weighted primary vector common to each of the channels and an ambience vector.
A method for determining primary and ambient components of a signal, the method comprising:
- converting for each subband left and right channels of the audio signal to corresponding frequency-domain vectors;
- and
- decomposing the left and right channel vectors into ambient and primary components by cross-channel orthogonal projection for determining the ambience in the right channel as orthogonal to the left channel vector and the ambience in the left channel as orthogonal to the right channel vector.
A method for determining primary and ambient components of a signal, the method comprising:
- extracting an ambience signal from a stereo pair;
- and
- determining an ambience-free primary signal as the residual after extraction of the ambience signal.
A method for determining primary and ambient components of at least a two channel signal having respective channels xL and xR, the method comprising:
- determining vectors vL and vR,
- orthogonally projecting the originals xL and xR onto those respective vectors to determine the primary components of the original signal;
- and
- determining the ambience as the projection residual.
The method as recited in claim 14 wherein vL and vR comprise a common vector for the left and right channels and the common vector is determined as the principal eigenvector determined by principal component analysis.
The method as recited in claim 14 wherein vL is equal to or a scaled version of xR and vR is equal to or a scaled version of xL and vL and vR are determined by cross-channel projection.
Dependencies are inferred from the claim text.