| 摘要 |
PURPOSE:To reduce the necessity of sending a signal uselessly and to improve the transmission efficiency by applying forced inter-frame prediction when a significant difference exists between frames actually and an orthogonal conversion coefficient or the like is to be sent. CONSTITUTION:A counter 41 reads out 'the number of times of a difference of prediction between frames by orthogonal conversion' from an orthogonal conversion frequency memory 42 in each block and when it is discriminated that a difference is large by a difference quantity discrimination circuit 6, after the value is increased by one, the result is stored again in the orthogonal conversion frequency memory 42. The frequency is compared with a predetermined threshold level by a discrimination circuit 43 and when they are identical, a switch 33 is switched to apply inter-frame prediction forcibly. Thus, the propagation of the block storing an error arithmetic accuracy is surely suppressed by the forced in-frame prediction and no forced in-frame prediction is adopted for a block having no movement in an object and the transmission of an orthogonal conversion coefficient or the like is not required. Thus, the reduction in the transmission efficiency is prevented. |
