Low complexity parametric stereo decoder

Abstract

A stereo audio decoder with low complexity is provided. A high stereo sound quality can be obtained with a limited computational power and is thus suitable for miniature and mobile equipment. The stereo decoder generates a set of stereo output channels (C1, C2) in response to a parametric audio input including signal parameters (S1) and stereo related parameters (X1). A parameter processor (M) generates two different set of parameters (P1, P2) based on the input signal parameters (S1) thus up-mixing the signal parameters (S1) by altering or manipulating the signal parameters (S1) corresponding to the stereo related parameters (X1). The two different parameters (P1, P2) are finally synthesized by separate signalsynthesizers (SS1, SS2) to form respective stereo output channels (C1, C2). Since the stereo decoding can be performed in the parameter domain instead ofthe spectral domain, the required computational burden is reduced compared to what is known in prior art. Preferably the signalsynthesizers (SS1, SS2) are sinusoidal synthesizers, and preferably the decoder also includes transient and noise synthesizers to generate transient and noise signal portions to be applied to the stereo output channels (C1, C2). Further, different transient and noise signalportions to the output channels (C1, C2) may be provided by applying different gains based on the stereorelated parameter (X1). In preferred embodiments the two parameters (P1, P2) are determined from a current as well as a previous signal parameter input, e.g. by means of an input delay line.

Description

technical field [0001] The invention relates to the field of audio coding. More particularly, the invention relates to stereo audio coding, in particular the invention provides an audio decoder arranged to decode a parametric audio signal into a stereo audio signal and a device comprising such a decoder. The present invention also provides a decoding method and computer-executable program code configured to perform such a method. Background technique [0002] Sine Coding (SSC) is a well-known parametric coding scheme capable of full-bandwidth high-quality audio coding, see for example [ISO / IEC 14496-3:2001 / AMD2, "Information Technology-Generic Coding of Audiovisual Objects. Part 3 : Audio.Amendment 2: High Quality Parametric Audio Coding (Information Technology - General Coding of Audiovisual Objects, Part III: Audio, Second Amendment: High Quality Parametric Audio Coding)"] and [Werner Oomen, Erik Schuijers, Bert "Advances in Parametric Coding for High-Quality Audio" by d...

AI Technical Summary

Problems solved by technology

But this solution has perceptual drawbacks, i.e. noise and transients sound "popped out" in the panning, and stereo decorrelation in the spectral domain is still a computationally intensive complex process

[0005] All in all, known stereo decoding methods are not suitable for devices where only limited signal processing capacity is available, such as mobile devices and small devices

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