Wideband audio over narrowband low-resolution media

This paper proposes a scheme of transmitting or storing a wideband audio stream in a channel or storage medium which is narrowband in nature and with a low resolution data format, such as an 8-bit companded one. In the proposed scheme, signal components in the upper-band part of the wideband beyond the narrowband - are encoded and then the code is embedded into the narrowband stream in a least audible way. As a result, this scheme enables the transmission and storage of wideband audio signals with the existing narrowband infrastructure. Furthermore, the scheme is fully backward compatible, i.e., conventional receivers, without the proposed decoding mechanism, can still access the narrowband audio with little audible degradation. The proposed scheme can find applications in areas where a high quality wideband audio is needed but the physical bandwidth is limited. Examples are voice-over-IP and telephony in general, as well as digital storage and playback.