Interactive audio services (IASs) usually provide users with audio editing functionality and they can render their own sounds according to their preference. For IASs, the spatial audio object coding (SAOC) is an appropriate multichannel coding tool that satisfies most of the required functionalities with relatively low bit rate. Nevertheless, the SAOC usually fails to remove a specific object successfully, especially the vocal object in the case of the Karaoke service. In addition, to expand the service to mobile environments, lower bit rate and complexity are required. Thus, we propose a new SAOC vocal harmonic coding technique to improve the background music quality in the Karaoke service. Namely, utilizing the harmonic information of the vocal object, we removed the harmonics of the vocal object remaining in the background music. Our experimental results confirm that the background music quality is improved by the proposed algorithm even with the low bit rate and complexity.

An interactive audio service is a new conceptual audio service that provides the users with opportunities for a variety of experiences on the alternative and advanced audio services. In the interactive audio service, users can freely control various audio objects to make their own audio sounds. A spatial audio object coding (SAOC) is a useful technology that can support most parts of the interactive audio service with a relatively low bit-rate, but is very poor to perfect gain control of a certain audio object, i.e., the target audio object. In this paper, the SAOC with a two-step coding structure is proposed to efficiently handle the target audio object as well as the normal audio objects. A transform coded excitation (TCX) based residual coding scheme is presented in the context of the sound quality enhancement. From experimental results, it can be noted that the various audio objects can be successfully handled with respect to the bit-rate and the sound quality by using the proposed two-step coding structure SAOC.