Speech restoration system and method for concealing packet losses
First Claim
1. A speech restoration system for concealing packet losses, the system comprising:
- a demultiplexer that demultiplexes an input bit stream and divides the input bit stream into several packets;
a packet loss concealing unit that produces and outputs a linear spectrum pair (LSP) coefficient representing the vocal tract of voice and an excitation signal corresponding to a lost frame, when a packet loss occurs; and
a speech restoring unit that synthesizes voice using the packets input from the demultiplexer, outputs the result as restored voice, and synthesizes voice corresponding to a lost packet using the LSP coefficient and the excitation signal input from the packet loss concealing unit and outputs the result as restored voice when the lost packet is detected,wherein the packet loss concealing unit repeats linear prediction coefficients (LPCs) of a last-received valid frame, produces a first excitation signal for the lost frame using a time scale modification (TSM) method, and outputs the first excitation signal to the speech restoring unit, when the lost frame is voiceless, and produces a second excitation signal by re-estimating a gain parameter based on the first excitation signal and outputs the second excitation signal to the speech restoring unit, when the lost frame is voiced.
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Accused Products
Abstract
Provided are a speech restoration system and method for concealing packet losses. The system includes a demultiplexer that demultiplexes an input bit stream and divides the input bit stream into several packets; a packet loss concealing unit that produces and outputs a linear spectrum pair (LSP) coefficient representing the vocal tract of voice and an excitation signal corresponding to a lost frame, when a packet loss occurs; and a speech restoring unit that synthesizes voice using the packets input from the demultiplexer, outputs the result as restored voice, and synthesizes voice corresponding to a lost packet using the LSP coefficient and the excitation signal input from the packet loss concealing unit and outputs the result as restored voice when the lost packet is detected, wherein the packet loss concealing unit repeats linear prediction coefficients (LPCs) of a last-received valid frame, produces a first excitation signal for the lost frame using a time scale modification (TSM) method, when the lost frame is voiceless, and produces a second excitation signal by re-estimating a gain parameter based on the first excitation signal, when the lost frame is voiced.
17 Citations
15 Claims
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1. A speech restoration system for concealing packet losses, the system comprising:
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a demultiplexer that demultiplexes an input bit stream and divides the input bit stream into several packets; a packet loss concealing unit that produces and outputs a linear spectrum pair (LSP) coefficient representing the vocal tract of voice and an excitation signal corresponding to a lost frame, when a packet loss occurs; and a speech restoring unit that synthesizes voice using the packets input from the demultiplexer, outputs the result as restored voice, and synthesizes voice corresponding to a lost packet using the LSP coefficient and the excitation signal input from the packet loss concealing unit and outputs the result as restored voice when the lost packet is detected, wherein the packet loss concealing unit repeats linear prediction coefficients (LPCs) of a last-received valid frame, produces a first excitation signal for the lost frame using a time scale modification (TSM) method, and outputs the first excitation signal to the speech restoring unit, when the lost frame is voiceless, and produces a second excitation signal by re-estimating a gain parameter based on the first excitation signal and outputs the second excitation signal to the speech restoring unit, when the lost frame is voiced. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A speech restoration method of concealing packet losses, the method comprising:
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demultiplexing an input bit stream and dividing the bit stream into several packets; checking whether a loss in the packets occurs; producing a LSP coefficient that represents the vocal tract of voice when packet loss occurs; producing a first excitation signal by performing TSM on an excitation signal produced with respect to a lost frame by repeating LPCs of a last-received valid frame when the lost frame of the packet is voiceless, and producing a second excitation signal by estimating a gain parameter based on the first excitation signal when the lost frame of the packet is voiced; and synthesizing voice corresponding to the lost frame using the LSP coefficient and the first or second excitation signal and outputs restored voice when packet loss occurs. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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Specification