Method for spatial resolution enhancement of ambisonic audio based on sparse MDCT representation

Objectives. The problem of developing a method for spatial resolution enhancement of ambisonic audio which improves the efficiency of existing approaches to digital spatial sound representation is being solved. Methods. The proposed approach is based on time-frequency decomposition of the audio signal with subsequent extraction of a directional plane wave from each frequency component. The approach develops the core ideas of high-resolution plane wave expansion (HARPEX) and directional audio coding (DirAC) methods, utilizing the advantages of real-valued sparse decomposition. Results. Application of the proposed ambisonic spatial resolution enhancement method involves the use of real-valued frequency components, which, unlike complex ones, provide a simpler and more robust estimation of sound arrival direction. Sparse decomposition enables an accurate and unified approach to describing sounds of various nature – from transient to tonal. Conclusion. Practical results confirm the method's applicability for audio processing with resolution enhancement up to seventh-order ambisonics. The disadvantage of the method is its high computational complexity; however, it is suitable for applications that do not require real-time processing.