Audio Encoding Spectrum Suppression Using Pulse Index Arrays
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Solution Overview
Problem
The existing CELP component suppressing method requires significant memory and computational resources when performed in multiple stages, as it necessitates passing and determining values for all frequency components across layers, leading to increased memory usage and computation.
Innovation Solution
An encoding apparatus and method that store frequency indices in an array after transform coding in lower layers and pass this array to higher layers, allowing for simplified CELP suppression by multiplying output signals with suppression coefficients without determining values for each frequency component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the existing CELP component suppressing method is used in multiple stages, then sound quality is improved, but memory usage and computational requirements increase significantly
Solution Approach 1:
The patent extracts only the necessary information (frequency indices of pulses) from the transform coding process and stores it in a compact array. Instead of passing and processing all frequency component values across layers, only the essential pulse position information is retained and transmitted, significantly reducing memory requirements while maintaining the ability to perform CELP suppression.
Solution Approach 2:
The patent segments the frequency spectrum into discrete pulse positions that are identified and stored individually in an array. This segmentation allows the system to process and store only the relevant frequency components (where pulses occur) rather than all frequency components, reducing the overall data volume needed for multi-stage CELP suppression.
2Manufacturing precision
If the existing CELP component suppressing method is used in multiple stages, then sound quality is improved, but computational requirements increase significantly
Solution Approach 1:
The patent performs preliminary action by storing the frequency indices of pulses in an array during the transform coding stage. This pre-stored information is then directly used in subsequent CELP suppression stages without requiring re-determination or complex processing, eliminating redundant computations and reducing overall computational requirements while maintaining sound quality.
3Measurement precision
If all frequency component values are passed and determined across layers, then accurate CELP suppression is achieved, but memory usage increases
Solution Approach 1:
The patent extracts only the essential information needed for CELP suppression (the frequency indices of pulses) and stores this compact representation in an array. This extracted information is sufficient to identify which frequency components require suppression without needing to store and process all frequency component values, thereby maintaining suppression accuracy while minimizing memory usage.
Data Source
AI summary
This encoding device (100) is provided with: a CELP encoding unit (102) that decodes CELP encoded data resulting from CELP encoding an input signal, generating a CELP decoded signal; a transform encoding unit (106) that generates a decoded signal spectrum by decoding transform encoded data resulting from using the spectrum of the input signal and the suppression spectrum of suppressing using a first suppression factor to transform encode the amplitude of the spectrum of the CELP decoded signal, and that outputs an index of the transform encoded frequency component; a pulse index recording unit (107) that forms and records an array using the index; and a CELP component suppression unit (109) that uses a second suppression factor and the array to suppress the amplitude of the spectrum resulting from adding the decoded signal spectrum and the suppression spectrum.