Acoustic Environment Simulation Signal Level Control
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Solution Overview
Problem
Current methods for simulating acoustic environments in immersive audio, such as HRIR/BRIR convolution, face high computational complexity, especially when dealing with multiple audio objects, leading to increased processing load and potential battery life reduction in portable devices, and lack effective loudness control due to unknown signal levels and transfer functions.
Innovation Solution
A dual-ended approach that encodes and decodes immersive audio by determining and transmitting signal level data and transform parameters, allowing for reconstruction of the simulation input signal and applying signal level modifications to ensure accurate acoustic environment simulation without requiring the decoder to measure signal levels, thereby reducing processing load and maintaining loudness preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HRIR/BRIR convolution is applied for every input object or channel separately to simulate acoustic environment, then the acoustic simulation accuracy is improved, but the computational complexity grows linearly with the number of channels or objects
Solution Approach 1:
The patent segments the acoustic simulation process into two independent parts: (1) rendering the first audio signal presentation from audio components, and (2) determining the simulation input signal for acoustic environment simulation. This segmentation allows parallel processing and reduces the computational burden of applying HRIR/BRIR convolution to every channel separately.
Solution Approach 2:
The patent extracts the simulation input signal from the rendered audio signal presentation through a separate determination process. By taking out the simulation input signal determination as an independent step, the system avoids redundant convolution operations and reduces computational complexity while maintaining acoustic simulation accuracy.
2Measurement precision
If high computational complexity processing is applied to simulate acoustic environment for multiple audio objects, then the immersive audio quality is improved, but the battery life is reduced
Solution Approach 1:
The patent performs preliminary rendering of the first audio signal presentation and preliminary determination of the simulation input signal before applying acoustic environment simulation. By preparing these signals in advance, the system reduces the real-time computational load during playback, thereby conserving battery life while maintaining immersive audio quality.
3Measurement precision
If the decoder measures signal levels to apply signal level modification, then the loudness control accuracy is improved, but the processing load and latency are increased
Solution Approach 1:
The encoder determines signal level data indicative of the simulation input signal level in advance and includes it in the encoded bitstream. This preliminary determination eliminates the need for the decoder to measure signal levels in real-time, reducing both processing load and latency while maintaining loudness control accuracy.
Solution Approach 2:
The patent uses the signal level data determined by the encoder as a copy of the actual signal level information, which is then transmitted to the decoder. This copying approach allows the decoder to apply signal level modification without performing measurements, thereby reducing processing load and latency.
4Measurement precision
If the encoder determines and transmits signal level data and transform parameters, then the loudness preservation is improved, but the data transmission load is increased
Solution Approach 1:
The patent determines signal level data specifically for the simulation input signal, which is a localized and targeted measurement rather than analyzing the entire audio signal. This localized approach reduces the amount of data that needs to be transmitted while still achieving effective loudness preservation.
Data Source
AI summary
Encoding/decoding an audio signal having one or more audio components, wherein each audio component is associated with a spatial location. A first audio signal presentation (z) of the audio components, a first set of transform parameters (w(f)), and signal level data (β2) are encoded and transmitted to the decoder. The decoder uses the first set of transform parameters (w(f)) to form a reconstructed simulation input signal intended for an acoustic environment simulation, and applies a signal level modification (α) to the reconstructed simulation input signal. The signal level modification is based on the signal level data (β2) and data (p2) related to the acoustic environment simulation. The attenuated reconstructed simulation input signal is then processed in an acoustic environment simulator. With this process, the decoder does not need to determine the signal level of the simulation input signal, thereby reducing processing load.