Method for speech coding, method for speech decoding and their apparatuses
AssigneeBlackBerry Limited
InventorTadashi Yamaura
Life of this patent
Estimating the term…
Abstract
A high quality speech is reproduced with a small data amount in speech coding and decoding for performing compression coding and decoding of a speech signal to a digital signal. In speech coding method according to a code-excited linear prediction (CELP) speech coding, a noise level of a speech in a concerning coding period is evaluated by using a code or coding result of at least one of spectrum information, power information, and pitch information, and various excitation codebooks are used based on an evaluation result.
Claims14
A speech decoding method at a decoder for synthesizing speech signals, the method comprising:
- receiving, at the decoder, a coded speech signal including an adaptive code, an excitation code, and a gain code;
- determining an adaptive code vector from an adaptive codebook based on the adaptive code;
- determining a decoded adaptive code vector gain by decoding the gain code;
- determining a decoded excitation vector by decoding the excitation code, the decoded excitation vector having a number of samples with zero amplitude;
- modifying, at the decoder, the decoded excitation vector based on the decoded adaptive code vector gain such that the number of samples with zero amplitude is changed;
- weighting the adaptive code vector by the decoded adaptive code vector gain;
- and
- synthesizing a speech signal based on the modified decoded excitation vector and the weighted adaptive code vector.
A speech decoding apparatus for synthesizing speech signals, comprising:
- a memory;
- and
- at least one hardware processor communicatively coupled with the memory and configured to:
- receive a coded speech signal including an adaptive code, an excitation code, and a gain code;
- determine an adaptive code vector from an adaptive codebook based on the adaptive code;
- determine a decoded adaptive code vector gain by decoding the gain code;
- determine a decoded excitation vector by decoding the excitation code, the decoded excitation vector having a number of samples with zero amplitude;
- modify the decoded excitation vector based on the decoded adaptive code vector gain such that the number of samples with zero amplitude is changed;
- weight the adaptive code vector by the decoded adaptive code vector gain;
- and
- synthesize a speech signal based on the modified decoded excitation vector and the weighted adaptive code vector.
Dependencies are inferred from the claim text.