Transient Signal Envelope Adjustment for Pre-Echo Recovery
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Solution Overview
Problem
Current bandwidth extension technologies for speech signals, particularly in encoding transient signals, suffer from pre-echo issues due to the lack of modification of time envelopes, resulting in unsatisfactory recovery of transient signals during decoding.
Innovation Solution
A method and device for transient signal encoding and decoding that involve identifying a reference sub-frame with the maximal time envelope and adjusting the amplitude values of preceding sub-frames to create a more distinct difference, ensuring the adjusted time envelope is written into a bitstream for improved recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the time envelope of transient signals is not modified during encoding, then the encoding process is simple, but pre-echo occurs and the recovery quality is unsatisfactory
Solution Approach 1:
The patent applies preliminary action by modifying the time envelope before encoding the transient signal. Specifically, it identifies the time envelope of the transient signal, adjusts its amplitude values, and then proceeds with the encoding process. This preliminary modification prevents pre-echo artifacts and improves recovery quality without adding complex processing during the main encoding stage.
2Manufacturing precision
If the amplitude values of all sub-frames are modified equally, then the processing is simple, but the distinct characteristics of transient signals are not preserved
Solution Approach 1:
The patent applies local quality by differentiating the modification process based on the position of sub-frames relative to the transient signal. It identifies that sub-frames before the transient signal require different amplitude adjustment than those after, and applies specific modification rules to each region. This preserves the distinct transient characteristics while maintaining processing efficiency through localized rather than uniform modification.
Data Source
AI summary
A transient signal encoding method and device, decoding method and device, and processing system, where the transient signal encoding method includes: obtaining a reference sub-frame where a maximal time envelope having a maximal amplitude value is located from time envelopes of all sub-frames of an input transient signal; adjusting an amplitude value of the time envelope of each sub-frame before the reference sub-frame in such a way that a first difference is greater than a preset first threshold, in which the first difference is a difference between the amplitude value of the time envelope of each sub-frame before the reference sub-frame and the amplitude value of the maximal time envelope; and writing the adjusted time envelope into bitstream.