MOD file format

Offset   Length   Contents
  0     20 bytes  Song name
[ // Sample informations
        22 bytes  Sample name
         2 bytes  Sample Length
         1 byte   Fine tunning    (0..7 => 0..7, 8..15 => -8..-1)
         1 byte   Volume [0..64]
         2 bytes  Loop start
         2 bytes  Loop length
]{31}
950      1 byte   Song length
951      1 byte   ?? (I don't know what it is)
952    128 bytes  Song positions
1080     4 bytes  Magic
                  "M.K."  // Protracker 4 channel
                  "M!K!"  // Protracker 4 channel
                  "FLT4"  // Startracker 4 channel
                  "FLT8"  // Startracker 8 channel
                  "4CHN"  // Fasttracker 4 channel
                  "6CHN"  // Fasttracker 6 channel
                  "8CHN"  // Fasttracker 8 channel
                  "CD81"  // Atari oktalyzer 8 channel
                  "OKTA"  // Atari oktalyzer 8 channel
                  "16CN"  // Taketracker 16 channel
                  "32CN"  // Taketracker 32 channel
                  "    "  // 15-instrument 4 channel
[ // Patterns
  [ // Tracks
         4 bytes  Data for pattern
  ]{nchannels * 64}
]{MAX Positions}
        ?? bytes  Samples