From Heavy Iron Modding

FMOD is an audio engine used in all Good and some Evil engine GameCube games. It uses *.fsb (FMOD Sample Bank) files to store audio data and *.fev (FMOD Event) files to control the playback of a sound (GoodEngine only). EvilEngine stores all sample banks in SNDI assets in HIP/HOP level archives, while GoodEngine stores them externally in a "media" folder. All sample banks are not encrypted and in little-endian.

Below is a table of all games and platforms which use fmod and their version.

FMOD version in games
Game (EvilEngine) GameCube FSB
The SpongeBob SquarePants Movie 3.73 3.1
The Incredibles
The Incredibles: Rise of the Underminer 3.74
Ratatouille Prototype
Game (GoodEngine) Wii Xbox 360 PS3 PC FSB
Ratatouille - Unknown Unknown - 3.1
Wall-E 4.12.07 Unknown Unknown - 3.1/4
Up 4.20.03 Unknown Unknown -
SpongeBob's Truth or Square 4.24.16 Unknown - - 4
UFC Personal Trainer 4.32.00 Unknown Unknown -
Hollywood Workout 4.35.02 Unknown - -
FGUY: Back to the Multiverse - Unknown Unknown 4.35.02

Format (FMOD Sample Bank)[edit]

FSB Header[edit]

0x18 (FSB3) or 0x30 (FSB4) bytes header

Offset Type Variable Description (FSB3) Description (FSB4)
0x00 char[4] id "FSB3" in ASCII "FSB4" in ASCII
0x04 s32 numsamples Amount of samples (sounds) in FSB
0x08 u32 shdrsize Size in bytes of all sample headers
0x0C u32 datasize Size in bytes of all compressed sound data combining all sound entries
0x10 u32 version
  • 0x01000300 (3.1)
  • 0x00000400 (4.0)
0x14 u32 mode

Flags that apply to all samples. See Header Flags

  • EvilEngine - Always 0x02
  • GoodEngine - Always 0x10 or 0x20 or 0x40
FSB4 only
0x18 u64 hash -
0x20 guid guid - Globally unique identifier: AAAAAAAA-BBBB-BBBB-CCCC-CCCCDDDDDDDD

Sample Header[edit]

0x50 bytes sample header for first sound only in EvilEngine, and for every sound in GoodEngine.

Offset Type Variable Description (EvilEngine) Description (GoodEngine)
0x00 u16 size Sample length (0x50) + extended headers (if any)
0x02 char[30] name Sample name in ASCII
0x20 u32 lengthsamples Amount of samples in sound data
0x24 u32 lengthcompressedbytes Length in bytes of compressed sound data
0x28 u32 loopstart Start of loop in sample
0x2C u32 loopend End of loop in sample
0x30 u32 mode Sample Flags
0x34 s32 deffreq Frequency - Sample rate in Hz
0x38 u16 defvol Volume
0x3A s16 defpan Pan
0x3C u16 defpri Priority
0x3E u16 numchannels Amount of channels. 1 (Mono), 2 (Stereo), >2 (Multi-channel)
0x40 f32 mindistance Always 1.0
0x44 f32 maxdistance Always 1000000.0 Always 10000.0
0x48 s32 (u32) varfreq (size_32bits) Variable Frequency - null
  • Variable Frequency (Ratatouille, Wall-E, Up) - null
  • size_32bits (Truth or Square, UFC, Hollywood, FGUY) - Same as size but in 32bits
0x4C u16 varvol Variable Volume - null
0x4E s16 varpan Variable Pan - null

Sample Header Basic[edit]

Only present if the FMOD_FSB_SOURCE_BASICHEADERS flag is set. Basic sample header for every consecutive sample after the first one. This is always the case in EvilEngine which means every basic sample inherits all values of the first 0x50 bytes sample header (numchannels, frequency, ...) i.e. you cannot store mono and stereo or different frequency tracks in one FSB.

Offset Type Variable Description
0x00 u32 lengthsamples Amount of samples in sound data
0x04 u32 lengthcompressedbytes Length in bytes of compressed sound data

Extended Header[edit]

Extended header are only present if a specific flag is set and are appended to the end of a (basic) sample header.


Only present if the FSOUND_GCADPCM flag ist set. GCADPCM header for every channel (stereo has 2).

Offset Type Variable Description
0x00 s16[16] coef Decoder coefficients
0x20 u16 gain Gain factor. Always 0
0x22 u16 pred_scale Predictor and scale. This will be initialized to the predictor and scale value of the sample’s first frame.
0x24 s16 yn1 History data; used to maintain decoder state during sample playback
0x26 s16 yn2
0x28 u16 loop_pred_scale Predictor/scale for the loop point frame. If the sample does not loop, this value is zero
0x2A s16 loop_yn1 History data for the loop point. If the sample does not loop, this value is zero.
0x2C s16 loop_yn2


Only present if the FSOUND_SYNCPOINTS flag is set.

Offset Size Description
0x00 4 "SYNC" in ASCII
0x04 4 Amount of entries
0x08 4 Offset in samples, relative to start of sound data
0x0C 256 Name (Not present if the FSOUND_SYNCPOINTS_NONAMES flag is set)


Only present if the FSOUND_XMA flag is set. Ratatouille and Wall-E Xbox360 use XMA1, every game after that XMA2 (with a few exceptions).

Offset Size Description
0x00 4 Unknown - usually 0x20
0x04 3 Unknown
0x07 1 Unknown - Always 0, 1 or 2
0x08 4 Unknown - Always 3, 19, 35, 36 or 51
0x00 12 Unknown - Always 0
Seek Table
0x0C 4 Length in bytes of seek table, relative to end of this
0x10 4 Unknown - Always 1
0x14 4 Amount of offsets in seek table. Always +1 if XMA2
0x18 4[] Array of offsets


Note: Only flags that occur are listed.

FSB Header Flags[edit]

0x02 = FMOD_FSB_SOURCE_BASICHEADERS   [Samples have basic headers]
0x10 = FMOD_FSB_SOURCE_NOTINTERLEAVED [Sample data is not interleaved]
0x20 = FMOD_FSB_SOURCE_MPEG_PADDED    [MPEG frames are aligned to the nearest 2 bytes, 16 bytes for multichannel]
0x40 = FMOD_FSB_SOURCE_MPEG_PADDED4   [MPEG frames are aligned to the nearest 4 bytes, 16 bytes for multichannel]

Sample Header Flags[edit]

0x00000001 = FSOUND_LOOP_OFF       [For non looping samples]
0x00000010 = FSOUND_16BITS         [For 16-bit samples]
0x00000020 = FSOUND_MONO           [For mono samples]
0x00000040 = FSOUND_STEREO         [For stereo samples]
0x00000100 = FSOUND_SIGNED         [For user created source data containing signed data]
0x00000200 = FSOUND_MPEG           [For MPEG layer 2/3 data]
0x00001000 = FSOUND_HW3D           [Attempts to make samples use 3d hardware acceleration]
0x00002000 = FSOUND_2D             [Tells software (not hardware) based sample not to be included in 3d processing]
0x00004000 = FSOUND_SYNCPOINTS_NONAMES [Specifies that syncpoints are present with no names]
0x00008000 = FSOUND_DUPLICATE      [This subsound is a duplicate of the previous one i.e. it uses the same sample data but w/different mode bits]
0x00080000 = FSOUND_HW2D           [2D hardware sounds. Allows hardware specific effects]
0x00400000 = FSOUND_IMAADPCM       [Contents are stored compressed as IMA ADPCM]
0x00100000 = FSOUND_3D             [3D software sounds]
0x01000000 = FSOUND_XMA            [For Xbox360 only - Contents are compressed as XMA format]
0x02000000 = FSOUND_GCADPCM        [For Gamecube/Wii only - Contents are compressed as Gamecube/Wii DSP-ADPCM format]
0x04000000 = FSOUND_MULTICHANNEL   [Contents are interleaved into a multi-channel (more than stereo) format]
0x10000000 = FSOUND_MPEG_LAYER3    [Data is in MP3 format]
0x20000000 = FSOUND_IMAADPCMSTEREO [Signify IMA ADPCM is actually stereo not two interleaved mono]
0x80000000 = FSOUND_SYNCPOINTS     [Specifies that syncpoints are present]