| 摘要 |
A speech codec (100, 200) for a speech communications unit includes a set of at least two embedded vector codebooks 256,262 capable of representing an input speech signal by a series of vectors. The codebooks 256, 262 share at least some common vectors of the series of vectors. The speech codec includes means for classifying 252 an input speech signal by selecting one of the codebooks in conjunction with at least a portion of at least one other embedded vector codebook to represent the input speech signal. The speech codec provides the advantage that at least two embedded vector codebooks, having overlapping vectors, can represent both wideband and narrowband signals. This provides for a reduced memory requirement of the codebook, in a memory constrained speech unit. Methods of generating such a combined vector codebook and encoding /decoding speech signals related to the combined vector codebook are disclosed. Application to video codecs is also envisaged. |
