Internal Channel Audio Conversion With Reduced Covariance Load
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Solution Overview
Problem
The complexity of format conversion in decoders increases when processing immersive audio signals with a large number of input channels, leading to increased battery consumption and reduced operating speed in mobile devices due to the need for extensive covariance calculations.
Innovation Solution
The method involves using internal channel gains based on MPEG Surround 212 parameters and rendering parameters to generate internal channel signals, reducing the number of input channels to the format converter, thereby simplifying covariance analysis and reducing calculation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all input channels are decoded and immersive audio signal is downmixed to stereo format, then format conversion is achieved, but decoder complexity increases due to extensive covariance calculations
Solution Approach 1:
The patent segments the format conversion process into two distinct stages: first performing MPEG Surround 212 decoding to generate intermediate channel signals, then conducting covariance analysis only on these reduced intermediate channels before final stereo downmixing. This segmentation reduces the number of channels requiring covariance calculations from the original multi-channel input to a smaller set of intermediate channels, thereby reducing decoder complexity while maintaining format conversion capability
Solution Approach 2:
The patent applies preliminary action by performing MPEG Surround 212 decoding and generating intermediate channel signals before the covariance analysis stage. This preliminary processing reduces the dimensionality of the data that subsequently requires covariance calculations, allowing the system to achieve format conversion with reduced computational complexity in the covariance analysis stage
2Measurement precision
If extensive covariance calculations are performed for format conversion, then accurate stereo downmixing is achieved, but battery consumption increases and operating speed decreases
Solution Approach 1:
The patent segments the covariance calculation process to be performed only on intermediate channel signals generated after MPEG Surround 212 decoding, rather than on all original input channels. This segmentation maintains the accuracy of stereo downmixing by performing covariance analysis on relevant intermediate channels while reducing the total number of calculations required, thereby improving operating speed without sacrificing downmixing accuracy
Solution Approach 2:
The patent changes the parameter space by transforming the original multi-channel input signals through MPEG Surround 212 decoding into a different representation (intermediate channel signals) that requires fewer covariance calculations. This parameter transformation maintains the essential information needed for accurate stereo downmixing while reducing the computational burden, thus improving operating speed while preserving accuracy
Data Source
AI summary
To address the technical problem, provided is a method of processing an audio signal, and the method including: receiving an audio bitstream that is encoded by using MPEG surround 212 (MPS212); obtaining internal channel gains with respect to one channel pair element (CPE) based on MPS212 parameters and rendering parameters about MPS212 output channels defined in a format converter; generating an internal channel signal with respect to the CPE based on the received audio bitstream and the obtained internal channel gains; and generating stereo output channel signals based on the generated internal channel signal.