Method and device for encoding wideband speech, allowing in particular an improvement in the quality of the voiced speech frames

摘要

A method for encoding speech includes sampling speech to obtain successive voice frames each having a predetermined number of samples, and determining parameters of a linear prediction model for each voice frame. The parameters include a long-term excitation word extracted from an adaptive coded directory using a first linear prediction filter and an associated long-term gain. The parameters further include a short-term excitation word extracted from a fixed coded directory and an associated short-term gain. The adaptive coded directory is updated based upon the extracted long-term excitation word and the extracted short-term excitation word. The first linear prediction filter is updated using the short-term excitation word filtered by a second filter. The second filter has an order greater than or equal to 1 and coefficients thereof depend on the long-term gain for reducing a short-term excitation contribution when a long-term excitation gain is greater than a threshold.