Patent ID: 8010351
Filing Date: 2011-08-30
Classification: G10L

Abstract:
1. A speech coding computer implemented method of significantly reducing error propagation due to voice packet loss while still greatly profiting from a pitch prediction or Long-Term Prediction (LTP), the method comprising: having an adaptive excitation component generated by multiplying a pitch gain (a scaling factor) with an adaptive vector produced from a past excitation with the pitch prediction; having a coded excitation component; adding the adaptive excitation component and the coded excitation component together to generate an excitation as an input to a Linear Prediction or Short-Term Prediction (STP) filter; determining an initial value of the pitch gain for every subframe within a frame of speech signal by minimizing a coding error or a weighted coding error at an encoder; reducing or limiting the value of the pitch gain to be smaller than the initial value of the pitch gain for the first subframe within the frame, in order to diminish impact of pitch correlations at the boundary of the frame when the voice packet loss happens; keeping the value of the pitch gain to be equal to the initial value of the pitch gain for any other subframe rather than the first subframe within the frame so that the pitch prediction is still efficient; encoding the pitch gain for every subframe of the frame at the encoder; and sending the encoded pitch gain for every subframe of the frame to a decoder.