Object-Based Audio Loudness Compensation Across Rendering Scenes
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Solution Overview
Problem
Conventional audio rendering technologies face challenges in maintaining consistent loudness across different audio programs and channels, leading to annoying volume fluctuations during switching, as they lack accurate and immediate loudness estimation and compensation mechanisms.
Innovation Solution
A decoder and encoder system that receives audio object signals and loudness information, using signal processors to determine loudness compensation values based on rendering information, ensuring the output loudness matches or closely resembles the input loudness by adjusting the audio object signals, even when rendering scenes change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If audio object signals are rendered with different rendering scenes, then audio output quality and flexibility are improved, but loudness consistency deteriorates
Solution Approach 1:
The encoder pre-calculates and stores loudness information for different rendering scenes before transmission. This preliminary action allows the decoder to immediately retrieve and apply the appropriate loudness compensation value without real-time calculation delays, ensuring consistent loudness across scene transitions while maintaining rendering flexibility
Solution Approach 2:
The system implements a feedback mechanism where loudness information from the encoder is transmitted to the decoder, which then applies loudness compensation based on this feedback. This closed-loop approach ensures that the output loudness matches the reference loudness regardless of rendering scene changes, resolving the contradiction between flexibility and consistency
2Stability of the object's composition
If loudness compensation is applied in real-time, then loudness consistency is improved, but processing complexity increases
Solution Approach 1:
Loudness compensation values are pre-calculated and embedded in the bitstream during encoding, eliminating the need for complex real-time loudness analysis at the decoder. The decoder simply retrieves and applies these pre-computed values, maintaining loudness consistency while minimizing processing complexity
Solution Approach 2:
Instead of performing complex loudness calculations, the system copies pre-calculated loudness information from the encoder to the decoder. This copying approach transfers the computational burden to the encoder side and simplifies the decoder architecture while maintaining accurate loudness control
3Manufacturing precision
If rendering information is transmitted for each audio object, then audio output quality is improved, but data transmission volume increases
Solution Approach 1:
The loudness information serves multiple functions: it characterizes the audio objects for accurate rendering, provides reference for loudness compensation, and enables adaptive playback across different devices. This multi-functionality justifies the additional data transmission by delivering comprehensive control information in a single parameter set
Solution Approach 2:
The system transmits compact loudness parameters (such as integrated loudness values) rather than full audio signals or complex metadata. This parameter-based approach maintains high audio output quality while minimizing data transmission volume through efficient encoding of essential characteristics
Data Source
AI summary
A decoder for generating an audio output signal having one or more audio output channels is provided. The decoder includes a receiving interface for receiving an audio input signal including a plurality of audio object signals, for receiving loudness information on the audio object signals, and for receiving rendering information indicating whether one or more of the audio object signals shall be amplified or attenuated. Moreover, the decoder includes a signal processor for generating the one or more audio output channels of the audio output signal. The signal processor is configured to determine a loudness compensation value depending on the loudness information and depending on the rendering information. Furthermore, the signal processor is configured to generate the one or more audio output channels of the audio output signal from the audio input signal depending on the rendering information and depending on the loudness compensation value. Moreover, an encoder is provided.