| 摘要 |
PURPOSE:To reduce degradation in quality by changing the value of the adaptive processing parameter of a decoding means accompanied by an adaptive processing for a constant period in the case of scrapping a packet. CONSTITUTION:A packet scrapping detection circuit 150 detects the presence/ absence of the scrapping of the packet and which packet out of the one of odd sampling system or the one of even sampling system a scrapped packet is based on the information of SEQ, and sends a result to an encoding system reproduction circuit 170. An adaptive processing parameter value control circuit 190 controls the parameter values of the predictor and the quantizer of an Embedded ADPCM decoder 180 based on the output of the packet scrapping detection circuit 150. When the packet is scrapped, it is possible to reduce the past influence of the adaptive processing by changing a leak factor that is the parameter of the adaptive processing to a large value, and to make an encoder and the decoder recover to a synchronous operation quickly. |
