Audio Decoding with Selective Temporal Envelope Shaping
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Solution Overview
Problem
Existing audio decoding technologies suffer from significant distortion in the time domain for frequency bands encoded with a small number of bits, leading to quality degradation.
Innovation Solution
The audio decoding device and method shape the temporal envelope of frequency bands encoded with a small number of bits into a desired temporal envelope using selective temporal envelope shaping, which includes filtering with a linear prediction inverse filter and adjusting the temporal envelope based on decoding-related information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a small number of bits are allocated for encoding a frequency band, then the bit rate is reduced, but the distortion in the time domain increases and quality degrades
Solution Approach 1:
The patent applies preliminary action by shaping the temporal envelope of the decoded signal in the frequency band before final output. The temporal envelope shaping unit pre-processes the decoded signal by adjusting its temporal envelope based on information from the encoder, ensuring that even with limited bits, the time domain representation maintains lower distortion and better quality.
Solution Approach 2:
The patent changes parameters by modifying the temporal envelope characteristics of the decoded signal. The temporal envelope shaping unit adjusts parameters such as the envelope shape and timing based on encoder information, transforming the decoded signal to reduce time domain distortion while maintaining low bit rate encoding.
2Manufacturing precision
If transform coding with adaptive bit allocation is used, then high quality is achieved at low bit rate, but distortion remains significant in the time domain for frequency bands with very small allocated bits
Solution Approach 1:
The patent introduces an intermediary element - the temporal envelope shaping unit - that acts as a mediator between the frequency domain decoding process and the final time domain output. This unit receives decoded signals from the transform coding process and applies temporal envelope shaping based on encoder information, bridging the gap between frequency domain efficiency and time domain quality.
Solution Approach 2:
The temporal envelope shaping is applied as a preliminary action to the decoded signal in frequency bands with very small allocated bits. By pre-shaping the temporal envelope before final reconstruction, the system compensates for information loss that would otherwise occur in the time domain.
Data Source
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AI summary
The purpose of the present invention is to reduce distortion a frequency band component encoded with a small number of bits in a time domain and improve quality. An audio decoding device (10) decodes an encoded audio signal and outputs the audio signal. A decoding unit (10a) decodes an encoded sequence containing an encoded audio signal and obtains a decoded signal. A selective temporal envelope shaping unit (10b) shapes a temporal envelope of a decoded signal in the frequency band on the basis of decoding related information concerning decoding of the encoded sequence.