Headphone Spatial Audio Rendering with Head Tracking
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Solution Overview
Problem
Existing methods for rendering spatial audio over headphones struggle to efficiently detect and adapt to small head movements, leading to a lack of realism in audio perception.
Innovation Solution
A processor configured to provide binaural signals to headphones, modified by head tracking hardware to enhance realism, using efficient head tracking modifications of audio processed by Binaural Room Impulse Response filters, with modest increases in memory storage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If head tracking modifications are applied to enhance realism, then audio perception realism is improved, but memory storage requirements increase
Solution Approach 1:
The patent segments the audio processing into distinct components: Binaural Room Impulse Response (BRIR) filtering for spatial positioning and head tracking modifications for movement detection. By separating these functions, the system can apply head tracking only when needed rather than processing entire audio streams continuously, reducing overall memory requirements while maintaining realism during head movements.
Solution Approach 2:
The system dynamically adjusts processing based on detected head movement. When head tracking hardware detects movement, the system applies modified filtering to maintain audio realism. When no movement is detected, the system uses standard processing, thereby reducing memory storage requirements while preserving realism only when necessary.
2Measurement precision
If head tracking modifications are applied to detect small head movements, then spatial audio perception is improved, but processing complexity increases
Solution Approach 1:
The patent introduces head tracking hardware as an intermediary device that specifically detects head movements and provides this information to the audio processing system. This intermediary handles the complex task of movement detection separately, allowing the main audio processing to remain relatively simple while still achieving high precision in detecting small head movements.
Solution Approach 2:
The system performs preliminary detection of head movements using dedicated tracking hardware before applying complex audio processing. By detecting movements in advance and only then applying sophisticated filtering when movements are detected, the system reduces overall processing complexity while maintaining high measurement precision for spatial audio perception.
3Reliability
If BRIR filtering is used to replicate room acoustics, then audio realism is improved, but processing time increases
Solution Approach 1:
The patent applies BRIR filtering selectively rather than continuously. Full BRIR processing is applied only when head movements are detected or when the system determines enhanced realism is necessary. During static listening conditions, the system uses reduced processing, thereby decreasing processing time while maintaining audio realism when it matters most.
Solution Approach 2:
The system dynamically adjusts the level of BRIR processing applied based on listening conditions. When head tracking detects movement, full BRIR filtering is engaged to maintain realism. During periods of no movement, the system reduces processing intensity, balancing audio realism with processing time efficiency.
Data Source
AI summary
A headphone for spatial audio rendering includes a first database having an impulse response pair corresponding to a reference speaker location. A head sensor provides head orientation information to a second database having rotation filters, the filters corresponding to different azimuth and elevation positions relative to the reference speaker location. A digital signal processor combines the rotation filters with the impulse response pair to generate an output binaural audio signal to transducers of the headphone. Efficiencies in creating impulse response or HRTF databases are achieved by sampling the impulse response less frequently than in conventional methods. This sampling at coarser intervals reduces the number of data measurements required to generate a spherical grid and reduces the time involved in capturing the impulse responses. Impulse responses for data points falling between the sampled data points are generated by interpolating in the frequency domain.