| 摘要 |
<p>PURPOSE:To round off an orthogonal transform coefficient at coding and to prevent deterioration in the picture quality by eliminating a signal component corresponding to a part of the orthogonal transform coefficients to an inter-frame prediction signal of a decoding picture signal at a decoder side. CONSTITUTION:At the decoder side, a waveform 519 corresponding to a coefficient rounded off by the coder side from waveforms 518, 519 corresponding to each orthogonal transform coefficient included in inter-frame prediction signal 517 is rounded off as a waveform 514 and a waveform 522 being the inversion of the orthogonal transform coefficient corresponding to the waveforms 508, 509 from the coder side is added to obtain a picture signal of waveform 515. A waveform 507 corresponding to the transform coefficient rounded off by a quantizer 16 from component waveforms 506, 507 included in a prediction signal 505 at the coder side is rounded off to form a waveform 510 and it is added to a waveform 520 being the result of inverting the orthogonal transform coefficient corresponding to the waveforms 508, 509 obtained by the quantizer 16 to form a local decoding signal with a waveform 512. Through the constitution above, the level difference between the output waveform 515 and the input waveform 501 is decreased to suppress the deterioration in the decoded picture signal.</p> |
