Envelope-Based Spatial Parameter Estimation in Directional Audio Coding

Directional Audio Coding provides an efficient description of spatial sound in terms of few audio downmix signals and parametric side information, namely the direction-of-arrival (DOA) and diffuseness of the sound. This representation allows an accurate reproduction of the recorded spatial sound with almost arbitrary loudspeaker setups. The DOA information can be efficiently estimated with linear microphone arrays by considering the phase information between the sensors. Due to the microphone spacing, the DOA estimates are corrupted by spatial aliasing at higher frequencies affecting the sound reproduction quality. In this paper we propose to consider the signal envelope for estimating the DOA at higher frequencies to avoid the spatial aliasing problem. Experimental results show that the presented approach has great potential in improving the estimation accuracy and rendering quality.