| 摘要 |
The decoder receives a bit stream representative of an audio signal, with a flag indicating any missing frames. For each frame, an excitation signal is formed from excitation parameters recovered in the bit stream if the frame is valid and estimated otherwise if the frame is missing, and the excitation signal is filtered by means of a synthesis filter to obtain a decoded audio signal. A linear prediction analysis is performed on the basis of the decoded audio signal obtained up to the preceding frame to estimate at least in part a synthesis filter relating to the current frame, whereby the successive synthesis filters used to filter the excitation signal, as long as there is no missing frame, conform to the estimated synthesis filters. If a frame n0 is missing, at least one synthesis filter used to filter the excitation signal relative to a subsequent frame n0+i is determined by a weighted combination of the synthesis filter estimated in relation to frame n0+i and at least one synthesis filter that has been used since frame n0. |
