My hacky method for converting samples to use as digidrums in ttrak

4bi-conv.c

#include <stdio.h>
#include <string.h>

int main(int argc, char **argv) {
    if (argc != 3) {
        fprintf(stderr, "%s in.raw (signed 8-bit mono PCM, little-endian) out.4bi", argv[0]);      
        return 1;
    }

    FILE *in  = fopen(argv[1], "rb"), *out = fopen(argv[2], "wb");

    while (!feof(in)) {
        int c = fgetc(in); fgetc(in);
        fputc(c / 0x11, out);
    }
    fclose(in);
    fclose(out);
    return 0;
}

readme.md

Converting wav samples to 4bi digidrums for ttrak

step 1

compile 4bi-conv.c from below:

gcc 4bi-conv.c -O0 -o 4bi-conv

step 2

Convert wav sample to raw signed 8-bit mono PCM with SoX:

sox input.wav -b 8 -c 1 -r 11025 -L -e signed-integer intermediary.raw

step 3

Conver raw 8-bit PCM to 4-bit PCM with 4bi-conv:

4bi-conv intermediary.raw output.4bi