Effcient multichannel audio resynthesis by subband-based spectral conversion

Multichannel audio offers significant advantages for music reproduction that include the ability to provide better localization and envelopment, as well as reduced imaging distortion. On the other hand, multichannel audio is one of the most demanding media types in terms of transmission requirements. A novel architecture was previously proposed, allowing delivery of uncompressed multichannel audio over high-bandwidth communications networks. In most cases, however, bandwidth limitations prohibit transmission of multiple audio channels. In such cases, an alternative would be to transmit only one or two reference channels and recreate the rest of the channels at the receiving end. In this paper, we propose a system that is capable of synthesizing the required signals from a smaller set of signals recorded in a particular venue. These synthesized “virtual” microphone signals can be used to produce multichannel recordings that accurately capture the acoustics of the particular venue. Applications of the proposed system include transmission of multichannel audio over the current Internet infrastructure and, as an extension of the methods proposed here, remastering of existing monophonic and stereophonic recordings for multichannel rendering.