/* Convert linear byte samples to 4-bit 3db/step log samples. */
/* Pack the output samples 2 to a byte. */

#include <stdio.h>

const int step[16] =
{
    0x01, 0x01, 0x02, 0x03, 0x05, 0x07, 0x0B, 0x0F,
    0x16, 0x1F, 0x2D, 0x3F, 0x5A, 0x7F, 0xB5, 0xFF
};

int samp[65536];

main()
{
        int c;
        int i, diff, min_diff, l;
        int b, j, e;
        int tot = 0, cnt = 0, x, max = 0, min = 0xFFFF, avg;

        j = b = 0;
        while ((c = getchar()) != EOF)
        {
                c &= 0xFF;
                samp[cnt++] = c;
        }

        /* Filter out 60Hz hum */
        for (i = 0; i < cnt; i++)
        {
                c = samp[i] = samp[i] + samp[i + 150];

                tot += c;
                if (c > max) max = c;
                if (c < min) min = c;
        }

        avg = tot / cnt;
        /* normalize */
        for (i = 0; i < cnt; i++)
        {
                c = samp[i];
                c -= avg;
                c *= 256 / (max - avg);
                if (c < 0) c = 0;
                samp[i] = c;
        }

        x = 0;
        e = 0;
        while (x < cnt)
        {
                c = samp[x++] + e;

                l = -1;
                min_diff = 0x1000;
                for (i = 0; i < 16; i++)
                {
                        diff = abs(c - step[i]);
                        if (diff < min_diff)
                        {
                                l = i;
                                min_diff = diff;
                        }
                }

                e = c - step[l];

                b = b << 4;
                b |= (l & 15);

                if (j & 1)
                {
//                      if ((j&0xE)==0) printf(" DCW  ");
//                      printf("$%.2X%c", b & 0xFF, (x==(cnt-1)) || (j&0xE)==0xE ? '\n' : ',');
                        printf("00 %.2X%c",b & 0xFF,(x==(cnt-1)) || (j&0xE)==0xE ? '\n' : ' ');
                }
                j++;
        }
        printf("\n");
        return 0;

}