Advanced stereo coding based on a combination of adaptively selectable left/right or mid/side stereo coding and of parametric stereo coding
AssigneeDolby International AB
InventorsHeiko Purnhagen, Pontus Carlsson, Kristofer Kjoerling
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Abstract
Methods and systems for advanced stereo processing of an audio signal are disclosed. The methods and systems include selecting a coding mode of either transform coding or linear predictive coding and performing advanced stereo processing when in the selected coding mode. Both encoding and decoding operations are provided.
Claims13
An audio signal processing device for encoding a stereo signal to a bitstream signal, the audio signal processing device comprising one or more components that:
- generate a downmix signal, a residual signal, and one or more parametric stereo parameters based on the stereo signal, wherein the residual signal indicates an error associated with representing the stereo signal by the downmix signal and the one or more parametric stereo parameters and wherein the one or more parametric stereo parameters comprise a parameter indicating a channel level difference;
- generate an SBR encoded downmix signal and mono SBR parameters in response to the downmix signal;
- generate, in a frequency-variant or frequency-invariant manner, a first signal and a second signal based on either:
- a sum of the SBR encoded downmix signal and the residual signal and a difference of the SBR encoded downmix signal and the residual signal;
- or
- the downmix signal and the residual signal;
- generate an encoded stereo signal by perceptual encoding the first signal and the second signal;
- and
- generate the bitstream signal by combining the one or more parametric stereo parameters, the mono SBR parameters, and the encoded stereo signal.
A audio signal processing device for decoding a bitstream signal including mono SBR parameters and one or more parametric stereo parameters to a stereo signal, the audio signal processing device comprising one or more components that:
- generate a first signal and a second signal by perceptual decoding the bitstream signal;
- generate, in a frequency-variant or frequency-invariant manner, a downmix signal and a residual signal based on either:
- a sum of the first signal and of the second signal and a difference of the first signal and of the second signal;
- or
- the first signal and the second signal;
- wherein the residual signal indicates an error associated with representing the first signal and the second signal by the downmix signal and the one or more parametric stereo parameters and wherein the one or more parametric stereo parameters comprise a parameter indicating a channel level difference;
- and
- generate an SBR decoded downmix signal in response to the downmix signal and the mono SBR parameters;
- generate the stereo signal based on the SBR decoded downmix signal and the residual signal by an upmix operation, with the upmix operation being dependent on the one or more parametric stereo parameters.
A method, performed by an audio signal processing device, for decoding a bitstream signal including mono SBR parameters and one or more parametric stereo parameters to a stereo signal, the method comprising:
- generating a first signal and a second signal by perceptual decoding the bitstream signal;
- generating, in a frequency-variant or frequency-invariant manner, a downmix signal and a residual signal based on either:
- a sum of the first signal and of the second signal and based on a difference of the first signal and of the second signal;
- or
- the first signal and the second signal;
- wherein the residual signal indicates an error associated with representing the first signal and the second signal by the downmix signal and the one or more parametric stereo parameters and wherein the one or more parametric stereo parameters comprise a parameter indicating a channel level difference;
- generating an SBR decoded downmix signal in response to the downmix signal and the mono SBR parameters;
- generating the stereo signal based on the SBR decoded downmix signal and the residual signal by an upmix operation, with the upmix operation being dependent on the one or more parametric stereo parameters;
- and
- wherein the method is performed, at least in part, by one or more components of the audio signal processing device.
Dependencies are inferred from the claim text.