Read MP3 Description

// ID3v1 files
// https://en.wikipedia.org/wiki/ID3
// http://www.dreamincode.net/forums/topic/287707-read-mp3-tags-id3-v1-c/
// http://freemusicarchive.org/member/happypuppyrecords/30_seconds_or_less

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

#define MP3_FILENAME "John_Wesley_Coleman_-_07_-_Tequila_10_Seconds.mp3"

typedef struct
{
   char tag[3];         // 3 byte(s)
   char title[30];      //30 byte(s)
   char artist[30];     //30 byte(s)
   char album[30];      //30 byte(s)
   char year[4];        // 4 byte(s)
   char comment[30];    //30 byte(s)
   unsigned char genre; // 1 byte(s)
} mp3Tag ;


int main()
{
    /* Open MP3 binary file */
    FILE *file_ptr = NULL;
    file_ptr = fopen(MP3_FILENAME, "rb");
    if (!file_ptr)
    {
        perror("Error fopen()");
        return EXIT_FAILURE;
    }

    /* make new header struct */
    mp3Tag tag = {"NA", "NA", "NA", "NA", "NA", "NA", '\0'}; // NA = NOT-AVAILABLE

    // Seek to 128 bytes before the end of the file
    if (fseek(file_ptr, -1 * sizeof(mp3Tag), SEEK_END) == -1)
    {
        perror("Error fseek()");
        return EXIT_FAILURE;
    }

    // Read the tag
    if (fread(&tag, sizeof(mp3Tag), 1, file_ptr) != 1)
    {
        fprintf(stderr, "Error fread()\n");
        return EXIT_FAILURE;
    }

    fclose(file_ptr);

    // Make sure we've got what we expect.
    if (memcmp(tag.tag, "TAG", 3) == 0)
    {
        // Found the tag where we expected
        printf("Title ... %.30s\n", tag.title);
        printf("Artist .. %.30s\n", tag.artist);
        printf("Album ... %.30s\n", tag.album);
        printf("Year .... %.4s\n", tag.year);

        if (tag.comment[28] == '\0')
        {
            printf("Comment..%.28s\n", tag.comment);
            printf("Track ... %d\n", tag.comment[29]);
        }
        else
        {
            printf("Comment..%.30s\n", tag.comment);
        }
        printf("Genre ... %d\n", tag.genre);
    }
    else
    {
        fprintf(stderr, "Failed to find TAG\n");
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}