Apparatus and Method for Determining a Predetermined Characteristic Related to an Artificial Bandwidth Limitation Processing of an Audio Signal

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

This patent introduces an apparatus and methods for detecting and processing audio signals that have been artificially bandwidth-limited, such as by lossy compression or spectral enhancement methods. It evaluates the slope of the audio spectrum and cut-off frequencies to determine if and where bandwidth limiting or enhancement (like Spectral Band Replication) has occurred. Based on the detected characteristics, it can reduce artifacts such as 'birdies,' spectral gaps, or roughness via post-processing, even without side information from the original coding process.

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

• Automatic audio quality improvement in music streaming or broadcasting by detecting and repairing bandwidth-limited or compressed audio signals.
• Integration into audio decoders or playback devices (e.g., smart speakers, headphones, car audio) to enhance sound quality by reducing perceptual artifacts from compression.
• Forensic audio analysis to detect previous compression or tampering based on bandwidth limitation and spectral features.
• Restoration of old or heavily compressed audio recordings by identifying and compensating for lost high-frequency content.
• Telecommunications and conference systems to enhance clarity of speech when low-bitrate codecs have been used.

BenefitsContent extracted from patent full text and abstract with AI.

• Provides robust, blind detection of artificial bandwidth limitation or enhancement processes, enabling post-processing without needing original encoding side information.
• Significantly reduces audio artifacts (e.g., 'birdies', spectral gaps, roughness), resulting in more pleasant and natural sound even at low bitrates.
• Adaptable to various audio characteristics (e.g., tonal/transient, speech/non-speech), allowing tailored restoration or enhancement strategies.
• Low computational complexity allows real-time implementation in consumer devices or professional audio systems.
• Helps prevent inappropriate post-processing on high-quality signals, preserving their fidelity while only enhancing degraded content.

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Patent Abstract

An apparatus for determining a predetermined characteristic related to an artificial bandwidth limitation processing of an audio signal comprises a slope evaluator configured for evaluating a slope of a spectrum of the audio signal to obtain a slope evaluation result. The apparatus comprises a frequency evaluator configured for evaluating a cut-off frequency of the spectrum of the audio signal to obtain a frequency evaluation result, and comprises a processor for providing an information indicating that the audio signal comprises the predetermined characteristic dependent on an evaluation of the slope evaluation result and an evaluation of the frequency evaluation result.