File Format: VAB

A proprietary format developed by Sony. Its purpose is to store custom samples, instrument attributes, etc.. Very similar concept to SoundFonts or DownLoadable Sounds (sf2/dls files). Developed solely for use on the PlayStation to better integrate with its sound hardware capabilities. It was used on many PlayStation games. Even though the standard extension is vab, it is more common to find it split into two pieces, a vh file (VAB header) and a vb file (VAB body). To get a full vab file out of the two, simply concatenate them.

The reason the files are commonly split in half, is so that the entire body can be loaded into the SPU buffer directly. The body file cannot be bigger than 512 kilobytes, as the buffer only has that much space. The maximum header size is 68128 bytes, meaning a full vab file has a maximum size of 592416 bytes, but it very rarely uses that much.

Header

The magic number should be "pBAV".

Name	Type	Endianness	Range	Default
Magic number	ASCII character x4	N/A
Version	Unsigned 32 bit integer	Little
VAB ID	Unsigned 32 bit integer	Little
Total file size	Unsigned 32 bit integer	Little
Reserved	Unsigned 16 bit integer	Little
Number of programs	Unsigned 16 bit integer	Little	0-128
Number of zones	Unsigned 16 bit integer	Little	0-255
Number of waves	Unsigned 16 bit integer	Little
Master volume	Signed 8 bit integer	N/A	0-127	127
Master panning	Signed 8 bit integer	N/A	0-127	64
Bank attributes 1	Unsigned 8 bit integer	N/A
Bank attributes 2	Unsigned 8 bit integer	N/A
Reserved	Unsigned 32 bit integer	Little

Program

The entire program section has a fixed size of 2048 bytes, each program using 16 bytes. This means there can be no more than 128 programs. If there are less then the remaining space is padded with zeros.

There is, however, an exception. If a program has 0 zones associated to it, then the program entry is empty. This means it reserves no zones when the structures get loaded. An empty program doesn't get counted in the total count of programs found in the main header, but it still exists and should be considered valid. It still occupies a slot of 16 bytes and must be accounted for.

For example:

0. 7 zones
1. 11 zones
2. 4 zones
3. 0 zones
4. 5 zones

While there are 5 programs in total, program number three has zero zones so the header will say there are only 4 in total.

Name	Type	Endianness	Range	Default
Number of program zones	Unsigned 8 bit integer	N/A	0-16
Program volume	Signed 8 bit integer	N/A	0-127	127
Program priority	Unsigned 8 bit integer	N/A
Program mode	Unsigned 8 bit integer	N/A
Program panning	Signed 8 bit integer	N/A	0-127	64
Reserved	Unsigned 8 bit integer	N/A
Program attribute	Unsigned 16 bit integer	Little
Reserved	Unsigned 32 bit integer	Little
Reserved	Unsigned 32 bit integer	Little

We used the "Program attribute" field as a way to support the multi-bank system used in SND files.

Zone

Each program is going to reserve an area of 512 bytes for its zones. Each zone occupies 32 bytes, leaving 16 zones per program. If less than 16 are used, the bytes must be padded with zeros.

Name	Type	Endianness	Range	Default
Zone priority	Unsigned 8 bit integer	N/A
Zone reverb volume	Unsigned 8 bit integer	N/A
Zone volume	Signed 8 bit integer	N/A	0-127	127
Zone panning	Signed 8 bit integer	N/A	0-127	64
Root key	Signed 8 bit integer	N/A	0-127	60
Pitch finetune	Signed 8 bit integer	N/A	0-127	0
Lowest key	Signed 8 bit integer	N/A	0-127
Highest key	Signed 8 bit integer	N/A	Lowest key-127
Vibrato width	Unsigned 8 bit integer	N/A
Vibrato time	Unsigned 8 bit integer	N/A
Portamento width	Unsigned 8 bit integer	N/A
Portamento holding time	Unsigned 8 bit integer	N/A
Pitch bending range minimum	Signed 8 bit integer	N/A
Pitch bending range maximum	Signed 8 bit integer	N/A
Reserved	Unsigned 8 bit integer	N/A
Reserved	Unsigned 8 bit integer	N/A
ADSR 1	Unsigned 16 bit integer	Little
ADSR 2	Unsigned 16 bit integer	Little
Parent program	Unsigned 16 bit integer	Little
Wave index	Unsigned 16 bit integer	Little	1-256
Reserved	Unsigned 16 bit integer	Little
Reserved	Unsigned 16 bit integer	Little
Reserved	Unsigned 16 bit integer	Little
Reserved	Unsigned 16 bit integer	Little

Waves Sizes

The entire wave sizes table has a fixed size of 512 bytes, each entry taking 2 bytes, allowing 256 waves.

The first entry is always 0, it is a dummy value that needs to be skipped. If there are 17 waves in the file, there will 18 entries in the list. The rest of the 512 byte chunk will be padded with zeros.

Offsets are not provided and must be calculated manually. The entries need to be multiplied by eight to get their true size in bytes.

Name	Type	Endianness
Wave sizes	Unsigned 16 bit integer array	Little

After the wave sizes, the body starts and continues until the end of the file. Waves are stored in Sony's proprietary ADPCM codec, also known as VAG.