Digital Signal Processing Library

Voice Lab

Program name: write_nsp_head

Language: C

In file: file_lib.c

Objective: write nsp header for file.

Usage: void write_nsp_head(FILE *out_file, int data_size, int sample_rate, int data_length);

Parameters:

• out_file - FILE Pointer to open file to write.
• data_size - Length of data word - typically 2 bytes.
• sample_rate - number of bits per sample - typically 16.
• data_length - amount of data to be written

• void

Mathematical Description:

Comments: Routine is used to write nsp header to an open file pointer

User Comments

Code:

void write_nsp_head(FILE *out_file, int data_size, int sample_rate, int data_length)
{
        int header_length;
        int size, i;
        time_t now;
        struct tm *times;
        char month[20], date_string[30], txt[120];

        fwrite("FORM", 1, sizeof("FORM")-1, out_file);
        fwrite("DS16", 1, sizeof("DS16")-1, out_file);

        /* This size should be the blocks from here to the end of the file */
        /* it should be the HEDR chunk(40) + Note Chunk(8 + note_string) + SDA chunk(8 + data_length) */
        /* Calculate size.... */
        strcpy(txt, "Repackaged by RRB. File downsampled to 25000");
        size = strlen(txt);
        if(size%2) size++;
        size += 40 + 8 + 8 + data_length;
        write_data(out_file, size, 4);

        fwrite("HEDR", 1, sizeof("HEDR")-1, out_file);

        size = 32;
        write_data(out_file, size, 4);

        time(&now);
        times = localtime(&now);
        switch(times->tm_mon) {
        case 0:
                strcpy(month, "Jan");
                break;
        case 1:
                strcpy(month, "Feb");
                break;
        case 2:
                strcpy(month, "Mar");
                break;
        case 3:
                strcpy(month, "Apr");
                break;
        case 4:
                strcpy(month, "May");
                break;
        case 5:
                strcpy(month, "Jun");
                break;
        case 6:
                strcpy(month, "Jul");
                break;
        case 7:
                strcpy(month, "Aug");
                break;
        case 8:
                strcpy(month, "Sep");
                break;
        case 9:
                strcpy(month, "Oct");
                break;
        case 10:
                strcpy(month, "Nov");
                break;
        case 11:
                strcpy(month, "Dec");
                break;
        }
        sprintf(date_string, "%s %2d %2d:%2d:%2d %4d", month, times->tm_mday,
                times->tm_hour, times->tm_min, times->tm_sec, 1900+times->tm_year);
        fwrite(date_string, 20, sizeof(char), out_file);

        printf("Date: %s\n", date_string);

        write_data(out_file, sample_rate, 4);
        printf("Sample Rate: %d\n", sample_rate);

        write_data(out_file, data_size, 4);
        write_data(out_file, 0xFFFF, 2);
        write_data(out_file, 0xFFFF, 2);

        fwrite("NOTE", 1, sizeof("NOTE")-1, out_file);

        size = strlen(txt);
        write_data(out_file, size, 4);

        fwrite(txt, size, sizeof(char), out_file);
        if(size%2) {
                write_data(out_file, 0, 1);
        }

        fwrite("SDA_", 1, sizeof("SDA_")-1, out_file);

        size = data_length;
        write_data(out_file, size, 4);
        printf("Data length: %d\n", data_length);

        size = ftell(out_file);
}