A video-coding device and a video-decoding device, which are capable of assuring the necessary quality of a
video sequence even if a transmission error and / or a loss of information occurs in a
transmission line and preventing the propagation of decoding error to subsequent images, and can effectively retransmit the necessary coded information when a transmission error and / or a loss of information occurs in a
transmission line. A motion-compensated interframe-predicting portion predicts an input image by using a preceding decoded image stored in a frame memory portion and outputs motion vectors. A difference calculating portion determines a difference between the input
image signal and the predicted
image signal and outputs the difference as a prediction-
error signal to a band-dividing portion which in turn divides the prediction-
error signal into n hierarchical
layers of frequency-band-components and outputs them to respective coding portions. A loop-back control portion decides whether each of the coded frequency-band-components of the coded prediction-
error signal from respective coding portions is input to a synthesizing portion and outputs a decoded prediction-error
signal. The predicted
image signal and the decoded prediction-error
signal are combined to generate a decoded image
signal corresponding to the input image. The decoded image signal is used for prediction of a subsequent input image. A motion-compensated interframe-predicting portion predicts an input image by using a preceding decoded image stored in a frame memory portion and outputs motion vectors. A difference calculating portion determines a difference between the input image signal and the predicted image signal and outputs the difference as a prediction-error signal to a band-dividing portion which in turn divides the prediction-error signal into n hierarchical
layers of frequency-band-components and outputs them to respective coding portions for quantizing and encoding the respective components. Buffer portions store the coded information and output the information to an
external circuit. The buffers output respective frequency-band-components of the coded information according to
retransmission request signals from a
retransmission control portion.