Macroblock
Sign in to saveThe macroblock is a processing unit in image and video compression formats based on linear block transforms, typically the discrete cosine transform (DCT). A macroblock typically consists of 16×16 samples, and is further subdivided into transform blocks, and may be further subdivided into prediction blocks. Formats which are based on macroblocks include JPEG, where they are called MCU blocks, H.261, MPEG-1 Part 2, H.262/MPEG-2 Part 2, H.263, MPEG-4 Part 2, and H.264/MPEG-4 AVC. In H.265/HEVC, the macroblock as a basic processing unit has been replaced by the coding tree unit.
Article · 中文
宏区块或宏块（英語：Macroblock）是一種影像壓縮的術語。 大區塊是运动预测的基本单位，一張完整的帧通常會被切割成幾個大區塊，MPEG-2和較早期的編解碼器定義大區塊都是8×8像素，現代的一點編解碼器像是H.263和H.264的大區塊通常都是16×16像素和相应区域内的Cb、Cr色差信号阵列共同组成。 大區塊為基準來選擇特定的預測類型，而非整個圖像都使用同樣的類型： * I圖像（Intra pictures）只可含有節點大區塊。 * P圖像（Predictive pictures）可含有節點大區塊或預測大區塊 。 * B圖像（Bi-predictive pictures）可含有節點、預測和前後預測大區塊。
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