God of Thunder Music Format

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God of Thunder Music Format
Format typeMusic
Notation typeOPL
Max channel count9 or 11
Max track count1
Max pattern count1
Max order count0

God of Thunder stores its music in this format. It is a raw Adlib format, containing the exact register and data pairs to send to the OPL chip.

File format

The file begins with a header specifying the offset (in words) of the beginning of loop, that is, where to start playing the song after it finishes. By default it is set to 0x0001 and the song will restart from the very beginning.

Data type Description
UINT16LE header Loop start offset from beginning of file (in words)

This is then immediately followed by a variable number of three byte chunks.

Data type Description
BYTE delay Number of ticks to wait *after* the data has been sent
BYTE reg OPL register to write to
BYTE val Value to write

In order to use delays larger than roughly 1 second, the format accepts a second delay byte when setting the MSB to 1 (it resembles MIDI lengths). For example,

 50      // Hex value 0x50
 80 D0   // Hex value 0xD0 ((0x80 & 0x7F) << 8) | 0xD0
 81 50   // Hex value 0x150 ((0x81 & 0x7F) << 8) | 0x50
 FF FF   // Hex value 0x7FFF (0xFF & 0x7F) << 8) | 0xFF

This allows a maximum delay of about 273 seconds (at 120 Hz).

The very last chunk has all values set to zero, plus a final 0x00 byte. The zero register/data pair designates the end of the song, so a footer metadata is possible but currently unused.


Songs are played at a different tempo (i.e. each delay tick lasts a different length of time): menu.got plays at 140 Hz, all other songs plays at 120 Hz. Known song lengths (based on Teppic's PCM recordings of in-game Adlib playback) are:

Song Length Notes
menu 1:15,759 in got.exe, not in gotres.dat
song11 1:41,457
song12 2:07,676
song13 1:07,647
song14 0:59,884
song21 1:19,258
song22 1:27,120
song23 0:34,845
song24 1:06,350
song25 1:39,959
song31 0:55,890
song32 0:58,659
opensong 1:19,821 Story song - slow version of song33
song33 1:13,730 in-game version of the story song
song34 1:11,795
song35 1:19,315
song36 0:47,887
winsong 0:32,918
bosssong 0:26,169


The following tools are able to work with files in this format.

Name PlatformPlay? Create new? Modify? Convert/export to other? Import from other? Access hidden data? Edit metadata? Notes
Camoto Linux/WinYesNoNoYes; manyYes; manyN/AN/A Incorrect tempo
GromPE's GoT unpacker WindowsNoNoNoYes; .imfNoN/AN/A Incorrect tempo
GromPE's OPL2WAV WindowsNoNoNoYes; .wavNoN/AN/A Incorrect tempo
Wombat WindowsNoNoNoYes; .imfNoN/AN/A Incorrect tempo


This file format was reverse engineered by Malvineous. If you find this information helpful in a project you're working on, please give credit where credit is due. (A link back to this wiki would be nice too!)