| 摘要 |
The method classifies speech, in particular speech signals, for the adaptive control of a speech encoding process. This encoding reduces the bit rate while keeping the speech quality the same, or increases the quality while keeping the bit rate the same. After segmenting the speech signal for each frame, a wavelet transformation is calculated. Using adaptive thresholds, a set of parameters is derived which control a state model. The speech frames are divided into sub-frames. Each sub-frame is divided into one of several typical classes for the speech encoding. The speech signal may be divided into segments of constant length. To reduce the edge effects with the wavelet transformation, either the segment at the boundaries is reflected or the wavelet transformation is calculated at smaller intervals. The frames are preferably shifted such that the segments overlap, or at the edges the segments are filled with previous or predicted sample values. |
