Neural Network Upmixing for Low-Complexity Multichannel Audio
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Solution Overview
Problem
Existing spatial audio encoding and decoding technologies, such as Parametric Stereo, introduce distortion and artifacts, leading to degraded audio quality, high computational complexity, and inefficient resource usage, particularly at the decoder side, while lacking flexibility for encoder-side control of decoder operations.
Innovation Solution
Employing a trained artificial neural network to generate an auxiliary audio signal for upmixing, using downmix and upmix parametric data, allowing reduced complexity and resource usage at the decoder while maintaining improved audio quality and flexibility through encoder-side control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional parametric stereo decoding is used, then audio quality is maintained, but computational complexity and resource usage at the decoder increase
Solution Approach 1:
The encoder pre-calculates and transmits control data values that guide the decoder's neural network processing. By performing complex analysis at the encoder side and providing simplified control signals to the decoder, the system maintains audio quality while reducing real-time computational burden at the decoder.
Solution Approach 2:
The patent replaces traditional signal processing operations with a trained neural network at the decoder. The neural network learns optimal upmixing strategies during training, substituting complex real-time calculations with pre-learned patterns that require fewer computational resources while maintaining or improving audio quality.
2Adaptability or versatility
If encoder-side control of decoder operations is implemented, then adaptability and audio quality improve, but system complexity increases
Solution Approach 1:
The control data values serve as an intermediary between the encoder and decoder. These compact parameters carry essential guidance information from the encoder to the decoder, enabling sophisticated encoder-side control without requiring complex real-time communication or synchronization mechanisms.
Solution Approach 2:
The system uses a set of control data values that parameterize the decoder's neural network operation. By transmitting these parameters from the encoder, the system enables dynamic adaptation of the decoding process to different audio content and encoding conditions without hardwiring complex control logic.
3Manufacturing precision
If neural network processing is used at the decoder, then audio reconstruction quality improves, but resource usage and computational load increase
Solution Approach 1:
The neural network is trained offline in advance on large datasets of audio content. This preliminary training phase allows the network to learn optimal reconstruction patterns that can be applied efficiently during actual decoding without requiring heavy computational resources at runtime.
Solution Approach 2:
Instead of implementing complex upmixing algorithms from scratch at the decoder, the system uses a copied neural network model that has been trained on comprehensive audio data. This pre-trained model encapsulates learned patterns that would be extremely resource-intensive to compute without the benefit of prior training.
Data Source
AI summary
An audio apparatus comprises a receiver (101) arranged to receive a data signal comprising downmix audio signal for a multichannel audio signal, upmix parametric data for upmixing the downmix audio signal, and set of control data values. An artificial neural network (107) has input nodes receiving second samples of the downmix audio signal and nodes receiving control data values from the set of control data values. Based on these inputs, the artificial neural network (107) generates samples of an auxiliary audio signal for the downmix audio signal. A generator (105) generates the multichannel audio signal from the downmix signal and the auxiliary audio signal in dependence on the upmix parametric data. Another apparatus may generate the set of control data values using another artificial neural network having input nodes receiving a downmix of the multichannel audio signal. In many embodiments, the operation may be subband based with separate artificial neural networks being used for different subbands.


