Dynamic Equalization for Cross-Talk Cancellation in Immersive Audio
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Solution Overview
Problem
The transmission and rendering of immersive audio content, particularly in formats like Dolby Atmos, become challenging when a substantial number of objects are used concurrently, especially on mobile devices operating on battery power, due to the complexity of processing and rendering time-varying metadata for dynamic objects and static objects.
Innovation Solution
A method involving the generation of binaural signal pairs based on intended spatial positions, applying cross-talk cancellation, and dynamic equalization or gain adjustment to the cross-talk cancelled signals, which can be frequency-dependent and based on loudspeaker and acoustic environment data, to produce a modified signal for improved audio rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cross-talk cancellation processing is applied to binaural signals, then audio rendering quality is improved, but decoder complexity increases
Solution Approach 1:
The cross-talk cancellation filters are pre-computed and stored in lookup tables based on acoustic environment parameters (distance, reverberation time, frequency). During decoding, the system performs simple lookup and multiplication operations rather than complex real-time filter computations, significantly reducing decoder complexity while maintaining audio rendering quality
Solution Approach 2:
The system transforms the cross-talk cancellation problem from time-domain complex filtering to frequency-domain parameter-based filtering. By representing filters as magnitude and phase parameters that can be pre-computed and stored, the system reduces real-time computational complexity while preserving audio quality
2Manufacturing precision
If dynamic equalization is applied to cross-talk cancelled signals, then audio quality across different acoustic environments is improved, but processing complexity increases
Solution Approach 1:
Dynamic equalization filters are pre-computed for various acoustic environments (different distances and reverberation times) and stored in lookup tables. The decoder selects and applies pre-computed equalization parameters based on metadata, avoiding real-time equalization computation while adapting to different acoustic environments
Solution Approach 2:
The system implements dynamic equalization by selecting from pre-computed filter sets based on acoustic environment parameters (distance, reverberation time). This provides adaptive equalization for different listening conditions while maintaining low computational complexity through parameter selection rather than real-time filter design
3Adaptability or versatility
If cross-talk cancellation and dynamic equalization are implemented, then compatibility with both loudspeakers and headphones is improved, but energy consumption increases
Solution Approach 1:
All computationally intensive operations (cross-talk cancellation filter computation, dynamic equalization filter computation) are performed in advance and stored in lookup tables. The mobile device decoder only performs simple parameter lookup and signal multiplication, dramatically reducing energy consumption while maintaining compatibility with both loudspeaker and headphone output
Solution Approach 2:
The patent introduces an intermediate representation where audio signals are processed through pre-computed filter banks that adapt to different output devices. This intermediary processing layer enables universal compatibility across device types while minimizing real-time computation on energy-constrained mobile devices
Data Source
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AI summary
A first playback stream presentation intended for reproduction on a first audio reproduction system and transform parameters may be received and decoded. The second playback stream presentation may be intended for reproduction on headphones. The transform parameters may be applied to an intermediate playback stream presentation to obtain the second playback stream presentation. The intermediate playback stream presentation may be the first playback stream presentation, a downmix of the first playback stream presentation, or an upmix of the first playback stream presentation. A cross-talk- cancelled signal may be obtained by processing the second playback stream presentation with a cross-talk cancellation algorithm. The cross-talk-cancelled signal may be processed by a dynamic equalization or gain stage wherein an amount of equalization or gain may be dependent on a level of the first playback stream presentation or the second playback stream presentation.