1. A method for coding of video pictures, wherein each of the video pictures is partitioned into largest coding units (LCUs) and each LCU is split into one or more coding units (CUs), and each of the video pictures is also partitioned into slices and each of the slices consists of multiple CUs , the method comprising: reconstructing each of the slices to form a reconstructed slice consisting of reconstructed CUs; if one or more first reconstructed samples required for a filtering process of a current reconstructed sample is in a same slice as the current reconstructed sample, applying the filtering process to the current reconstructed sample using said one or more first reconstructed samples; and if said one or more first reconstructed samples required for the filtering process of the current reconstructed sample is not in the same slice as the current reconstructed sample, performing one of: bypassing the filtering process for the current reconstructed sample, and applying the filtering process to the current reconstructed sample using one or more extended samples generated from one or more second reconstructed samples in the same slice to replace said one or more first reconstructed samples.