●●●●● ●●●● 2.4.2算术编码原理 ●●0 ●●● ●●●● b d 0.5 0.750.875 aa Had 0.25 0.375 0.5 aba abc -abd 0.25 03593750375 d 0.359375 0.3671875 0.375 0.359375∈[0,0.5)a (0.358875-0)/0.50.71875∈[0.5,0.75b (0.718750.5)/0.250.875∈[0.875,1d (0.8750.875)/025=0∈[0,0.5a2.4.2 算术编码原理 0.75 a b c d 0 0.5 0.875 1 aa ab ac ad 0 0.25 0.375 0.5 aba abb abc abd 0.25 0.359 375 0.375 a b c d 0.359 375 0.367 187 5 0.375 (0.875 0.875)/0.12 5 0 [0,0.5) a (0.71875-0.5)/0.250.875 [0.875,1) d (0.359 375 -0)/0.5 0.71875 [0.5,0.75) b 0.359 375 [0,0.5) a − =  → =  → =  →  →