Apparatus and Method for Processing an Audio Signal to Obtain a Processed Audio Signal Using a Target Time-Domain Envelope

Simple SummaryContent extracted from patent full text and abstract with AI.

This invention provides an apparatus and method for improving the processing and reconstruction of audio signals, particularly by enhancing the handling of transient components (such as drum hits or note onsets) in audio source separation, compression, and bandwidth enhancement. It achieves this by using information about a target time-domain envelope and applying it during phase reconstruction of frequency-domain frames, reducing artifacts like pre-echoes and improving perceptual quality, especially for separated or encoded signals.

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• High-quality music or speech source separation, allowing extraction of individual instruments or voices from complex recordings with preserved transients.
• Audio encoding and compression schemes (e.g., for streaming, broadcasting, or storage) that require better preservation of signal transients and reduced artifacts.
• Bandwidth extension and enhancement in codecs where upper frequency components are partly missing or approximated (e.g., parametric audio coding, intelligent gap filling).
• Audio restoration or up-mixing/remixing scenarios where clean separation and faithful transient reproduction are required.
• Forensic or audio analysis tools that need clear onset preservation for subsequent interpretation or processing.

BenefitsContent extracted from patent full text and abstract with AI.

• Reduces pre-echo and transient smearing artifacts common in conventional audio signal reconstruction, leading to higher perceptual audio quality.
• Improves clarity and definition of transient sounds (like drum hits, percussive notes, sudden speech onsets) in processed audio.
• Supports a variety of applications including source separation, audio compression, bandwidth enhancement, and audio restoration with a unified approach.
• Enables more accurate reconstruction with fewer iterations, thereby reducing computational complexity and processing time compared to existing iterative phase reconstruction methods.
• Is compatible with standard audio coding and source separation architectures, making it practically deployable in real-world systems.
• Maintains the spectral characteristics while ensuring a more natural and transparent reproduction of the original audio events.

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Patent Abstract

Subject of the invention is an apparatus (2) described by a schematic block diagram for processing an audio signal (4) to obtain a processed audio signal (6). The apparatus (2) comprises a phase calculator (8) for calculating phase values (10) for spectral values of a sequence of frequency-domain frames (12) representing overlapping frames of the audio signal (4). Moreover, the phase calculator 8 is configured to calculate the phase values (10) based on information on a target time-domain envelope (14) related to the processed audio signal (6), so that the processed audio signal (6) has at least in an approximation the target time-domain envelope (14) and a spectral envelope determined by the sequence of frequency-domain frames (12).