In this paper a new algorithm for digital video coding is presented that is suitable for digital storage and video transmission applications in the range of 5 to 10 Mbps. The scheme is based on frame differencing and, unlike recent proposals, does not employ motion estimation and compensation. A novel adaptive grouping structure is used to segment the video sequence into groups of frames of variable sizes. Within each group, the frame difference is taken in a closed loop Differential Pulse Code Modulation (DPCM) structure and then decomposed into different frequency subbands. The important subbands are transformed using the Discrete Cosine Transform (DCT) and the resulting coefficients are adaptively quantized and runlength coded. The adaptation is based on the variance of sample values in each subband. To reduce the computation load, a very simple and efficient way has been used to estimate the variance of the subbands. It is shown that for many types of sequences, the performance of the proposed coder is comparable to that of coding methods which use motion parameters.
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