H.264宏塊選擇的自適應算法研究

在視頻編碼的過程中,運動估計占據(jù)了舉足輕重的地位.其性能優(yōu)劣會在一定程度
上決定了碼流質(zhì)量.采用16×16 宏塊能夠提高壓縮比,但容易產(chǎn)生方塊效應,使用4×4
宏塊可以提高圖像質(zhì)量,但降低了壓縮比。H.264 視頻壓縮標準采用多模式運動估計,
可以有效減少塊匹配預測誤差,但隨著模式的增多,算法計算量成倍增加.為了克服這個
困難,本文提出一種新的自適應的宏塊劃分和運動估計算法。這種分塊算法在綜合考慮
圖像本身特性在編碼過程中,根據(jù)圖像的各個部分運動程度不同而采用不同的分快策
略,兼顧圖像質(zhì)量和處理開銷。
關(guān)鍵詞: H.264; 運動估計; 塊匹配
Abstract: Motion estimation plays an important role in video encoding. Its performance
affects the quality of encoded bit stream greatly. Using 16×16 macro block leads to serious
mosaic affection, Although it may be help to enhance the compression ratio. Using 4×4
macro block can improve picture quality easily comparing with previous method, but it
sacrifice the high compression ratio. Through the using of multi block pattern, H.264 gets
the balance between quality and compression ratio. With the increasing of macro block
patterns, computing complexity increases sharply. In order to avoid this dilemma, this
paper provides a new algorithm to accomplish this goal. According to the moving character
of the picture, the algorithm adopts diverse policy to get the balance between quality and
complexity