Video encoder and decoder apparatus deciding error in transform coefficients between an original image and a predictive image

A video transmission system comprising:

• a video encoder apparatus using distributed video coding (DVC) to encode an input sequence including a key frame and a non-key frame with respective encoding schemes different from each other to transmit at least partially an error correction code for an encoded non-key frame to a decoder, said encoder apparatus comprising:
• a key frame encoder for encoding the key frame and transmitting the encoded key frame to the decoder;
• and
• a non-key frame encoder for forming a predictive image of the non-key frame on a basis of the encoded key frame, and determining, based on a fallibility of a transform coefficient of the predictive image with respect to a transform coefficient of an original image of the inputted non-key frame, an amount of error correction codes to be transmitted to transmit the error correction codes associated with the determined amount of error correction codes,
• said non-key frame encoder transmitting, when no error is detected between the transform coefficients of the original image and the predictive image, information indicating no error detected, instead of the error correction code for the non-key frame,
• said system further comprising a video decoder apparatus using the DVC, wherein the encoded key frame and at least partially the error correction code are received from said encoder apparatus, the error correction code being in an amount corresponding to the fallibility of the transform coefficient of the predictive image with respect to the transform coefficient of the original image of the non-key frame, and a decoded key frame is used to form the predictive image of the non-key frame to perform the error correction on the predictive image with the error correction code,
• said decoder apparatus comprising a non-key frame decoder for forming the predictive image of the non-key frame in a manner in which the predictive image is formed on said encoder apparatus,
• said non-key frame decoder being operative in response to information, which indicates that no error is detected and is received instead of the error correction code for the non-key frame, to output the predictive image thus formed as a decoded image of the key frame.