| 摘要 |
PURPOSE:To suppress deterioration of the picture quality to the minimum by encoding reference sampled value and sampled value obtained from difference value between prediction value found from this reference sampled value and the reference sampled value-the difference value which is brought into compressed quantization, at every sampled value. CONSTITUTION:In an example of four pieces of sampled values shown by A4i-1, A4i, A4i+1 and A4i+2, a sampled value A4i shown with a mark O is encoded by (n) bits as a reference sampled value. Also, the sampled value A4i+1 shown with a mark X is not encoded and not transmitted. As for this sampled value which is not transmitted, a difference to a prediction value found from the reference sampled value A4i is brought to compressed encoding, but the prediction value is denoted as A4i, from which a difference is derived from the following expression, and these two pieces of difference data B4i-1=A4i-1-A4i, B4i+2=A4i+2-A4i are brought to compressed encoding by a bit number (m) (<n). In such a way, a quantization error based on the difference compressed encoding is not accumulated. Also, it can be prevented that an error propagation due to a code error generated on a transmission line extends over a long period.
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