Level Ratio Based Inter and Intra Channel Prediction with Application to Stereo Audio Frame Loss Concealment

The problem of side signal frame loss concealment for Mid/Side M/S stereo audio is addressed in this paper. The proposed level ratio based inter and intra channel LRIIC prediction method is designed to overcome the main challenge due to the diversified stereophonic nature of audio signals. To identify the stereophonic nature, we employ the time varying level ratio between mid also called monophonic signal and side signal. In the first phase, one Winer filter is designed from the monophonic signal and side signal of previous frame. And the other one is designed from the side signal of previous two frames. The two filters allow reconstruction of the current loss frame with inter and intra channel prediction respectively. In the second phase, available current frame of monophonic signal is used as the input of inter-channel Winer filter. While long-term prediction filter is employed to find the periodic components of previous frames as the input of intra-channel Winer filter. Finally, a level ratio based linear combination of inter and intra channel prediction output is employed to get the current lost side signal. Objective and subjective evaluation results for the proposed LRIIC approach, in comparison with existing techniques, all incorporated within a 3GPP AMR-WB+ decoder, provide evidence for gains across a variety of stereophonic signals.