AAMP
AAMPs are parameter files (officially: binary resource parameter archives).
Only version 2 is documented in this article since this is what Breath of the Wild and recent Nintendo games use.
Structure
AAMP is a (typically) little endian format.
Unlike some other file formats, AAMP files have the exact same structure and endianness on Wii U and Switch, so these files are interchangeable between the consoles.
- Parameters are a key-value pair. In the binary form, the key is a CRC32 hash.
- Parameter Objects are dicts that contain Parameters.
- Parameter Lists are structures that contain Parameters, Parameter Objects, and other Parameter Lists.
- The root parameter list is called the Parameter IO. It is associated with a version and type string in the header which is checked by the AAMP library.
Section order
- Header
- Parameter lists, objects, parameters (the official ordering algorithm is unknown)
- Data section (to store parameter data)
- String section (to store strings)
- Unknown uint32 section (unused?)
Header
| Offset | Type | Description |
|---|---|---|
| 0x0 | char[4] | Magic ("AAMP") |
| 0x4 | u32 | Version (2) |
| 0x8 | u32 | Flags (LittleEndian: 1 << 0, UTF8: 1 << 1) |
| 0xc | u32 | File size |
| 0x10 | u32 | Parameter IO version |
| 0x14 | u32 | Offset to parameter IO (multiple of 4) |
| 0x18 | u32 | Number of lists (including parameter IO) |
| 0x1c | u32 | Number of objects |
| 0x20 | u32 | Number of parameters |
| 0x24 | u32 | Data section size |
| 0x28 | u32 | String section size |
| 0x2c | u32 | Unknown: number of uint32s after the string section |
| 0x30 | char[] | Parameter IO type (typically xml)
|
Parameter list
| Offset | Type | Description |
|---|---|---|
| 0x0 | u32 | Name CRC32 |
| 0x4 | u16 | Offset to child lists, divided by 4 and relative to parameter list start |
| 0x6 | u16 | Number of child lists |
| 0x8 | u16 | Offset to child objects, divided by 4 and relative to parameter list start |
| 0xa | u16 | Number of child objects |
Parameter object
| Offset | Type | Description |
|---|---|---|
| 0x0 | u32 | Name CRC32 |
| 0x4 | u16 | Offset to child parameters, divided by 4 and relative to parameter object start |
| 0x6 | u16 | Number of child parameters |
Parameter
| Offset | Type | Description |
|---|---|---|
| 0x0 | u32 | Name CRC32 |
| 0x4 | u24 | Offset to data, divided by 4 and relative to parameter start. For strings, this points to a string in the string section. For other parameter types, this points to the data section. |
| 0x7 | ParameterType (u8) | Type |
ParameterType
The following parameter type and class names are official and come from Nintendo's AAMP library.
| ID | Type | Parameter type |
|---|---|---|
| 0 | bool | agl::utl::Parameter<bool>
|
| 1 | f32 | agl::utl::Parameter<float>
|
| 2 | int | agl::utl::Parameter<int>
|
| 3 | vec2 | agl::utl::Parameter<sead::Vector2<float>>
|
| 4 | vec3 | agl::utl::Parameter<sead::Vector3<float>>
|
| 5 | vec4 | agl::utl::Parameter<sead::Vector4<float>>
|
| 6 | color | agl::utl::Parameter<sead::Color4f>
|
| 7 | string32 | agl::utl::Parameter<sead::FixedSafeString<32>>
|
| 8 | string64 | agl::utl::Parameter<sead::FixedSafeString<64>>
|
| 9 | curve1 | agl::utl::ParameterCurve<1u>
|
| 10 | curve2 | agl::utl::ParameterCurve<2u>
|
| 11 | curve3 | agl::utl::ParameterCurve<3u> (unused in BotW?)
|
| 12 | curve4 | agl::utl::ParameterCurve<4u>
|
| 13 | buffer_int | agl::utl::ParameterBuffer<int>
|
| 14 | buffer_f32 | agl::utl::ParameterBuffer<float>
|
| 15 | string256 | agl::utl::Parameter<sead::FixedSafeString<256>>
|
| 16 | quat | agl::utl::Parameter<sead::Quat<float>>
|
| 17 | u32 | agl::utl::Parameter<uint>
|
| 18 | buffer_u32 | agl::utl::ParameterBuffer<unsigned int>
|
| 19 | buffer_binary | agl::utl::ParameterBuffer<unsigned char>
|
| 20 | stringRef | agl::utl::Parameter<sead::SafeStringBase<char>>
|
| 21 | (none, special) | agl::utl::Parameter<int *>, agl::utl::Parameter<float *>, agl::utl::Parameter<unsigned int *>, agl::utl::Parameter<unsigned char *>
|
Usage in Breath of the Wild
AAMP files are used in Breath of the Wild to store parameters that define the game's behaviour. They are very frequently used inside bactorpack archives, where they define most of an Actor's characteristics.
Naming conventions for arrays
Nintendo works around the lack of lists/arrays in the AAMP format by using parameter lists/objects and numbered names for children.
By convention, if the parent name is {parent name}, children will typically have one of the following names:
{singular parent name}_%d{singular parent name}_%02d{singular parent name}_%03d{singular parent name}%d{singular parent name}%02d{singular parent name}%03d
This is of course not the case for all documents and there are in fact many exceptions.
Extensions
AAMP files have a wide range of extensions. The file format is the same regardless of the extension, but the parameters defines inside it differ depending on the extension.
- bxml
- bas
- baglblm
- baglccr
- baglclwd
- baglcube
- bagldof
- baglenv
- baglenvset
- baglfila
- bagllmap
- bagllref
- baglmf
- baglshpp
- baiprog
- baslist
- bassetting
- batcl
- batcllist
- bawareness
- bawntable
- bbonectrl
- bchemical
- bchmres
- bdemo
- bdgnenv
- bdmgparam
- bdrop
- bgapkginfo
- bgapkglist
- bgenv
- bglght
- bgmsconf
- bgparamlist
- bgsdw
- bksky
- blifecondition
- blod
- bmodellist
- bmscdef
- bmscinfo
- bnetfp
- bphyscharcon
- bphyscontact
- bphysics
- bphyslayer
- bphysmaterial
- bphyssb
- bphyssubmat
- bptclconf
- brecipe
- brgbw
- brgcon
- brgconfig
- brgconfiglist
- bsfbt
- bsft
- bshop
- bumii
- bvege
- bactcapt
Internal usage
Parameter classes (e.g. Bdmgparam) inherit from agl::utl::IParameterIO -> agl::utl::IParameterList.
In their constructors or in an init function, agl::utl::Parameter objects are created and initialised by passing the key name, the description and help strings (see agl::utl::ParameterBase::initializeListNode). The CRC32 for the keys are stored and then the Parameter object is added to a agl::utl::IParameterObj list.
Finally, to actually load the AAMP binary data into all the parameter objects, the game constructs a agl::utl::ResParameterArchive::ResParameterArchive and then passes it to applyResParameterArchive().
Structures
agl::utl::ResParameterArchive holds a pointer to agl::utl::ResParameterArchiveData (which is the AAMP header structure).
Elements like param_root are parameter lists (agl::utl::IParameterList, tag: param_list). The binary structure for lists is agl::utl::ResParameterList.
A param list holds parameter objects (agl::utl::IParameterObj, tag: param_array) or other parameter lists. The binary structure for objects is agl::utl::ResParameterObj.
Param objects store parameters (agl::utl::ParameterBase, tag: param). The binary structure for parameters is agl::utl::ResParameter.
Parameter list name
agl::utl::IParameterIO (in Nintendo's AAMP library) automatically sets the 'parameter list name' / tag name to param_root.
al::Parameter
Super Mario Odyssey's al::Parameter classes are extremely similar to the agl::utl::Parameter utils and appear to be an improved version. They share most of the public interface, presumably because Nintendo wanted to make switching to al:: easier.
The human readable format is YAML instead of XML and the binary format uses BYML. Key names are stored in plain text unlike agl::utl::Parameter which stores only the hashes of the key strings.
- Parameters have the same purpose as in the agl:: implementation.
- ParameterLists are dicts (key-value mapping, with keys being strings) that contain Parameters, ParameterObjects, ParameterArrays and ParameterLists.
- ParameterObjects are dicts that contain Parameters and ParameterArrays.
- ParameterArrays are arrays of ParameterObjects. This is a new structure.
Tools
The following tools can be used to convert AAMP files to an editable format, and back again: