| 摘要 |
<p>An apparatus and method for coding and decoding digital video images, capable of maintaining the quality of static regions, such as background images, in decoded pictures even when the resolution of pictures has been changed from high to low. The apparatus is equipped with two storage units, low-resolution and high-resolution picture storage units (4,3), to hold reference pictures in two different picture formats. When processing coded blocks (or blocks having at least one non-zero transform coefficient), a high-resolution picture updating unit (13)converts corresponding blocks of a low-resolution reference picture retrieved from the low-resolution picture storage unit (4) to obtain high-resolution block images. It then updates a high-resolution picture stored in the high-resolution picture storage unit (3) with the obtained high-resolution block images. This updating operation is not applied on non-coded blocks. As a result, only active regions corresponding to the coded blocks are updated within the picture stored in the high-resolution picture storage unit (3), while the remaining part, which may possibly be static background images, is preserved without losing their high visual quality.</p> |
