check_wav

Digital Signal Processing Library

Voice Lab


check_wav

int check_wav(FILE *in_file_ptr, int *data_length, int *sample_rate)
{
        int header_length;
        int size;
        char header[MAX_HEADER_LENGTH];

        (*sample_rate) = -1;

        /* check if the file has a WAVe header */

        /* go to beginning of file */
        fseek(in_file_ptr,0,SEEK_SET);

        fread(&header, sizeof(char), 4, in_file_ptr);
        if(strncmp(header, "RIFF", strlen("RIFF")) != 0) {
                /* not wave header */
                fseek(in_file_ptr,0,0);
                return(0);
        }

        fread(&size, sizeof(char), 4, in_file_ptr);
        fread(header, sizeof(char), 4, in_file_ptr);
        if(strncmp(header, "WAVE", strlen("WAVE")) != 0) {
                /* not wave header */
                fseek(in_file_ptr,0,0);
                return(0);
        }
        fread(header, sizeof(char), 4, in_file_ptr);
        if(strncmp(header, "fmt ", strlen("fmt ")) != 0) {
                /* not wave header */
                fseek(in_file_ptr,0,0);
                return(0);
        }
        fread(&size, sizeof(char), 4, in_file_ptr); /* size of wave section chunk (usually 16) */
        fread(header, sizeof(char), 2, in_file_ptr); /* Type of WAVE format. */
        fread(header, sizeof(char), 2, in_file_ptr); /* mono (0x01) or stereo (0x02). */
        fread(&(*sample_rate), sizeof(char), 4, in_file_ptr); /* Sample rate. */
        fread(&size, sizeof(char), 4, in_file_ptr); /* Bytes/Second. */

        fread(header, sizeof(char), 2, in_file_ptr); /* Block alignment. */
        (*data_length) = header[0];

        fread(header, sizeof(char), 2, in_file_ptr); /* Bits/Sample. */
        printf("Bits per sample: %d\n", header[0]);

        fread(header, sizeof(char), 4, in_file_ptr);
        if(strncmp(header, "data", strlen("data")) != 0) {
                /* not valid wave header */
                fseek(in_file_ptr,0,0);
                (*sample_rate) = -1;
                return(0);
        }

        fread(&size, sizeof(char), 4, in_file_ptr);

        /* wave file found */
        header_length = ftell(in_file_ptr);
        return(header_length);
}