c-gcc, 127 bytes

Result

AC

Code [DL]

int i,a,b;main(){for(;a<50;a++){for(b=i=0;b++<8;){i+=getchar()&1;i*=2;}getchar();i/=2;for(b=0;i>0;)i-=b++;putchar(i<0?48:49);}}

stdin

00011100
01100100
10101010
11101011
00010000
01101101
10101011
00100100
10001000
11111101
10011001
11010111
11010100
10111110
11100111
11011100
00101101
00000110
00001101
10011100
00111111
01000010
10000110
01101001
11010010
11011101
00010101
10111111
00110010
10111001
00001010
00000011
01011011
00100010
01111000
00000001
11001100
10110101
01011001
00001010
00000000
11001011
00010110
00001111
11010110
01110101
00101001
11111101
01001110
00110111

stdout

10000011111001101100010110100011101100011001000111

stderr

/tmp/code.c:1:11: warning: return type defaults to ‘int’ [-Wimplicit-int]
 int i,a,b;main(){for(;a<50;a++){for(b=i=0;b++<8;){i+=getchar()&1;i*=2;}getchar();i/=2;for(b=0;i>0;)i-=b++;putchar(i<0?48:49);}}
           ^
/tmp/code.c: In function ‘main’:
/tmp/code.c:1:54: warning: implicit declaration of function ‘getchar’ [-Wimplicit-function-declaration]
 int i,a,b;main(){for(;a<50;a++){for(b=i=0;b++<8;){i+=getchar()&1;i*=2;}getchar();i/=2;for(b=0;i>0;)i-=b++;putchar(i<0?48:49);}}
                                                      ^
/tmp/code.c:1:107: warning: implicit declaration of function ‘putchar’ [-Wimplicit-function-declaration]
 int i,a,b;main(){for(;a<50;a++){for(b=i=0;b++<8;){i+=getchar()&1;i*=2;}getchar();i/=2;for(b=0;i>0;)i-=b++;putchar(i<0?48:49);}}
                                                                                                           ^

strace