QMF Audio Codec Resampling via Configurable Filter Bank Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current audio processing technologies face challenges in efficiently adapting to different sampling rates, particularly at low bit rates, which leads to compatibility issues with low-cost hardware and increased computational resources due to the need for additional resampling steps, especially in multimedia devices handling various audio sources.
Innovation Solution
The proposed solution involves a configurable audio signal processor with analysis and synthesis filter banks, controlled by a controller to adjust the number of channels and sampling rates, allowing for flexible sampling rate conversion by modifying the frequency domain representation, reducing the complexity of resampling and eliminating additional signal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional resampling functional modules (interpolator, up sampler, down sampler) are used to adapt output sampling rate, then sampling rate compatibility is improved, but computational resources and device complexity increase significantly
Solution Approach 1:
The patent merges the resampling function with the existing QMF filter bank structure by making the analysis and synthesis filter banks configurable. The same filter bank infrastructure is used for both audio processing and resampling, eliminating the need for separate resampling modules and reducing overall system complexity.
Solution Approach 2:
The filter banks are designed to be dynamically configurable, allowing the number of analysis and synthesis channels to be adjusted based on the desired sampling rate. This dynamic adaptation enables the system to handle different sampling rates without requiring fixed, dedicated resampling hardware for each rate.
2Adaptability or versatility
If additional resampling functional modules are used to adapt output sampling rate, then sampling rate compatibility is improved, but computational resources increase significantly
Solution Approach 1:
The resampling operation is combined with the existing filter bank processing. By configuring the filter bank channel counts appropriately, the resampling is performed as part of the normal audio decoding process, avoiding duplicate computational work and reducing overall energy consumption.
Solution Approach 2:
The QMF filter bank structure serves dual purposes: it performs both the audio signal processing function and the resampling function simultaneously. The filter bank inherently performs the sampling rate conversion when its channel configuration is adjusted, making the system self-sufficient and eliminating the need for additional dedicated resampling resources.
3Manufacturing precision
If unconventional sampling rates are used to increase audio bandwidth and scalability, then audio quality is improved, but compatibility with low-cost hardware D/A converters is worsened
Solution Approach 1:
The system uses dynamically configurable filter banks that can adapt their channel configuration based on the target sampling rate. This allows the system to output conventional sampling rates for hardware compatibility while maintaining the ability to process and represent higher quality audio through flexible internal processing configurations.
Data Source
AI summary
An apparatus for processing an audio signal includes a configurable first audio signal processor for processing the audio signal in accordance with different configuration settings to obtain a processed audio signal, wherein the apparatus is adapted so that different configuration settings result in different sampling rates of the processed audio signal. The apparatus furthermore includes n analysis filter bank having a first number of analysis filter bank channels, a synthesis filter bank having a second number of synthesis filter bank channels, a second audio processor being adapted to receive and process an audio signal having a predetermined sampling rate, and a controller for controlling the first number of analysis filter bank channels or the second number of synthesis filter bank channels in accordance with a configuration setting.