| 摘要 |
<p>PURPOSE:To improve picture quality of a decoded picture by implementing intra-coding when a macro block is coded and a variance in a predicted error of the macro block is larger than a threshold level so as to avoid the macro block not predicted excellently. CONSTITUTION:Figure shows a criterion of deciding intra-coding/prediction coding, the X axis indicates a variance (VAR) of a prediction error and the Y axis indicates a variance (VAROR) of an original signal. When the VAR is larger than a threshold level by using the criterion as above, intra-coding is implemented to implement coding without use of prediction not successful. The distribution of the VAR and VAROR is calculated in the frame coding in the setting of an optimum threshold level and the threshold level is decided so that number of macro blocks subject to intra-coding based on the distribution and the threshold level is used for the coding of a succeeding frame.</p> |
