PACKET LOSS CONCEALMENT METHOD USING PACKET INFORMATION, THAT IS, PITCH INFORMATION OF TWO PACKETS AND INFORMATION ON SPECTRAL DISTANCE BETWEEN THE PACKETS BEFORE/AFTER LOSS, AND RECORDING MEDIUM IN WHICH PROGRAM FOR REALIZING THE SAME METHOD IS STORED

摘要

PURPOSE: A PLC(Packet Loss Concealment) method using the packet information before/after loss is provided to compare both phonemes by using the pitch information obtained from two packets and the spectral distance between the packets before/after packet loss, and to compensate for a loss section with front/back phoneme information, thereby supplying more natural synthetic voice signals. CONSTITUTION: A receiving-side confirms that packet loss occurred during a VoIP(Voice over Internet Protocol) transmission(601). To conceal the packet loss, the receiving-side detects pitches from two packets before and after the loss(602). The receiving-side confirms whether the two packets are all the same as voiced sounds or voiceless sounds(603). If so, the receiving-side calculates the spectral distance between voice signals of the two packets(604), and compares the calculated spectral distance with the spectral distance between adjacent packets to check whether the different between the two spectral distance is big(605). If not, the receiving-side judges that the phonemes of the two packets are the same(606), and compensates for the entire packet loss section with the packet before the packet loss(607). If the different is big, the receiving-side judges the phonemes of the two packets are different(608), and compensates for two-thirds of the packet loss section with the phoneme of the packet before the packet loss and the rest with the phoneme of the packet after the loss(609).