| 摘要 |
<p>PURPOSE:To suppress the deterioration of picture quality to a low level by evaluating each block in a predictive error signal region or a discrete cosine transformation coefficient region, attaching priority on each block unit according to a certain rule, and selecting a variable speed channel corresponding to the priority. CONSTITUTION:A priority decision means 13 which attaches the priority on each block according to a certain rule by using the transformation coefficients in which a predictive error signal value or a predictive error signal in each block is transformed at a discrete cosine circuit 11, and selects the variable speed channels 14, 15 corresponding to attached priority is provided. Therefore, only a unique block (on which low priority is attached) not being prominent visually even when it is deleted is targeted to be deleted when a network is set in a congested state, and the unique block (on which high priority is attached) to generate remarkable deterioration visually when it is deleted is not deleted since it is transmitted on a variable speed high priority channel 14. In such a way, it is possible to suppress the deterioration of the picture quality to a low level even when the deletion of a packet due to the congestion of the network occurs.</p> |
