Multisignal Audio Coding Using Signal Whitening as Preprocessing

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This patent describes an advanced audio encoding and decoding technique for efficiently compressing three or more audio signals (such as multi-channel or 3D audio) by first applying signal whitening as preprocessing. Whitening reduces correlations and normalizes energy levels between channels, making them more suitable for efficient joint processing. The encoder then adaptively selects and encodes pairs of channels, taking advantage of similarities (correlations) between them using methods like mid/side (M/S) processing. The approach allows flexible, high-quality, low-bitrate encoding of complex audio scenes, especially for immersive or spatial audio applications.

Use CasesContent extracted from patent full text and abstract with AI.

• Streaming high-fidelity multi-channel or immersive (3D/360) audio with reduced bandwidth usage, such as for music or movies.
• Audio storage, transmission and playback in formats requiring multi-channel audio (5.1/7.1 surround, Ambisonics, etc.).
• Live broadcasting of events with spatial/immersive audio to achieve efficient use of network resources.
• Digital music distribution platforms requiring archival or delivery of spatial/master audio with minimal quality loss.
• Real-time audio communication platforms (e.g., conferencing, VR/AR) benefiting from high efficiency at low latency and bitrate.

BenefitsContent extracted from patent full text and abstract with AI.

• Significantly improves compression efficiency for audio with three or more channels, reducing required storage and transmission bandwidth.
• Maintains or improves perceptual audio quality by preprocessing (whitening) signals and adaptively exploiting inter-channel similarity.
• Provides a flexible codec architecture that can handle arbitrary channel configurations, supporting modern immersive and spatial audio use-cases.
• Reduces complexity and bit usage for encoding side information compared to prior techniques, especially during joint processing of highly correlated channels.
• Allows integration with both audio and speech codecs due to unified processing approach.
• Enables smarter bitrate distribution and adaptive coding based on input signals' energy and correlation, leading to better quality at the same bitrate.

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Patent Abstract

A multisignal encoder for encoding at least three audio signals, comprises: a signal preprocessor (100) for individually preprocessing each audio signal to obtain at least three preprocessed audio signals, wherein the preprocessing is performed so that a preprocessed audio signal is whitened with respect to the signal before preprocessing; an adaptive joint signal processor (200) for performing a processing of the at least three preprocessed audio signals to obtain at least three jointly processed signals or at least two jointly processed signals and an unprocessed signal; a signal encoder (300) for encoding each signal to obtain one or more encoded signals; and an output interface (400) for transmitting or storing an encoded multisignal audio signal comprising the one or more encoded signals, side information relating to the preprocessing and side information relating to the processing.