arithintdecod.m

一个详尽的算术编码的matlab仿真程序。

function seq=arithintdecod(btag,alpha,cnt,lgt)
CC(1)=0;
for i=1:length(cnt)
    CC(i+1)=CC(i)+cnt(i);
end
totcount=CC(i+1);
m=ceil(log2(totcount*4));
seq='';
l=0;
u=2^m-1;
for i=1:lgt
    ts=btag(1:m);
    t=bin2dec(ts);
    k=1;
    s=floor(((t-l+1)*totcount-1)/(u-l+1));
    while(s>=CC(k))
        k=k+1;
    end
        seq=[seq alpha(k-1)];
        l1=l+floor(((u-l+1)*CC(k-1))/totcount);
        u=l+floor(((u-l+1)*CC(k))/totcount)-1;
        l=l1;
       lb=dec2bin(l,m);
       ub=dec2bin(u,m);
       E2=1;E3=1;
       while (E2 | E3)
         fbl=lb(1);
         fbu=ub(1);
          if fbl==fbu
              E2=1;
             lb(1)='';
             lb(end+1)='0';
             ub(1)='';
             ub(end+1)='1';
             btag(1)='';
          else
             E2=0;
          end
         sbl=lb(2);
         sbu=ub(2);
         if sbl=='1' & sbu=='0'
             lb(1)='';
             lb(end+1)='0';
             ub(1)='';
             ub(end+1)='1';
             lb(1)='0';
             ub(1)='1';
             btag(1)='';
             if (btag(1)=='0')
                 btag(1)='1';
             else
                 btag(1)='0';
             end
             E3=1;
         else
             E3=0;
         end
       end
      u=bin2dec(ub);
      l=bin2dec(lb);
end
end