An improved spectral subtraction method in compressed domain

For audio noise reduction, the current research is mainly focused on the non compressed domain. As for the MP3 (MPEGl-layer3) compressed audio, the common noise reduction method is first fully decoding and then for the decoding audio carrying out noise reduction. This method costs a lot of time for decoding and it inevitably reduces the processing efficiency for compressed audio. In this paper, we present an improved spectral subtraction method based on MDCT-entropy activity detection method for noise estimation in compressed domain. The proposed algorithm works directly on MP3 frames. The experimental results show that the proposed algorithm can remove noise directly from noisy MP3 audio and its process efficiency is higher than common method. And the signal-to-noise ratio (SNR) of the compressed audio is improved obviously.