Moving picture decoding apparatus having three line buffers controlled

Abstract

A picture decoding apparatus has a memory for storing decoded picture data, three line buffers for temporarily storing picture data read from the memory, and a line buffer controller. Two of the three line buffers are selected sequentially and cyclically, and their operation modes are changed over to the writing mode, and decoded picture data read from the memory is stored sequentially in the two line buffers. The two line buffers are changed over from the writing mode to the reading mode sequentially and cyclically in the same order as that in which the two line buffers selected sequentially and cyclically were changed over to the writing mode, and data for one line is read sequentially from the two line buffers. While an earlier-selected one of the selected two line buffers is changed over to the reading mode and picture data for the former half of one line stored in the line buffer is read out therefrom, the remaining line buffer is changed over to the writing mode and picture data for the former half of a subsequent one line is stored therein. While a later-selected one of the two selected line buffers is changed over to the reading mode and picture data for the latter half of the said one line stored therein is read out therefrom, the earlier-selected line buffer is changed over to the writing mode and picture data for the latter half of the subsequent line is stored therein.