Audio coding with gain profile extraction and transmission for speech enhancement at the decoder

摘要

The invention provides a layered audio coding format with a monophonic layer and at least one sound field layer. A plurality of audio signals is decomposed, in accordance with decomposition parameters controlling the quantitative properties of an orthogonal energy-compacting transform, into rotated audio signals. Further, a time-variable gain profile specifying constructively how the rotated audio signals may be processed to attenuate undesired audio content is derived. The monophonic layer may comprise one of the rotated signals and the gain profile. The sound field layer may comprise the rotated signals and the decomposition parameters. In one embodiment, the gain profile comprises a cleaning gain profile with the main purpose of eliminating non-speech components and/or noise. The gain profile may also comprise mutually independent broadband gains. Because signals in the audio coding format can be mixed with a limited computational effort, the invention may advantageously be applied in a tele-conferencing application.

主权项

1. An audio encoding system for producing, based on an audio signal, a gain profile to be distributed with said audio signal, the gain profile comprising a time-variable voice activity gain and a time-variable and frequency-variable cleaning gain, wherein the audio encoding system comprises:
a voice activity detector adapted to determine the voice activity gain by at least determining voice activity in the audio signal; and a noise estimator adapted to determine the cleaning gain by at least estimating noise in said audio signal, wherein the cleaning gain is separable from the voice activity gain in the gain profile.