Frame error concealment

摘要

A frame error concealment method based on frames including transform coefficient vectors including the following steps: It tracks (S11) sign changes between corresponding transform coefficients of predetermined sub-vectors of consecutive good stationary frames. It accumulates (S12) the number of sign changes in corresponding sub-vectors of a predetermined number of consecutive good stationary frames. It reconstructs (S13) an erroneous frame with the latest good stationary frame, but with reversed signs of transform coefficients in sub-vectors having an accumulated number of sign changes that exceeds a predetermined threshold.

主权项

1. A frame error concealment method for improving audio quality, the method being performed by a decoder and comprising:
tracking sign changes between corresponding transform coefficients of sub-vectors of consecutive good stationary audio frames including a latest good stationary audio frame, each said sub-vector comprising a plurality of transform coefficients; accumulating the number of sign changes in corresponding sub-vectors of a number of consecutive good stationary audio frames; and reconstructing an erroneous frame with the latest good stationary audio frame to produce a reconstructed frame comprising a plurality of sub-vectors each comprising a plurality of transform coefficients, wherein, for each one of the sub-vectors of the reconstructed frame, there is an accumulated number of sign changes for that sub-vector such that each sub-vector has its own accumulated number of sign changes for use in determining the sign of the transform coefficients of the sub-vector, wherein the erroneous frame is reconstructed such that: for each transform coefficient included in the reconstructed frame, the absolute value of the transform coefficient is identical to the absolute value of a corresponding transform coefficient included in the latest good stationary audio frame, for each transform coefficient of the reconstructed frame that is included in a sub-vector that has an accumulated number of sign changes that exceeds a threshold, said transform coefficient has a sign that is reversed with respect to the sign of the corresponding transform coefficient included in the latest good stationary audio frame, and for each transform coefficient of the reconstructed frame that is included in a sub-vector that has an accumulated number of sign changes that is less than the threshold, said transform coefficient has a sign that is the same as the sign of the corresponding transform coefficient included in the latest good stationary audio frame.