File Format: SND and SMP

.snd/.smp is a proprietary format developed by Crystal Dynamics. Its purpose is to store sequences, custom samples, instrument attributes, etc... Very similar concept to Sony's format (.SEQ/.VH/.VB/.VAB) developed for the PlayStation, or in broader terms, it's a similar concept to MIDI files with their respective SoundFonts or DownLoadable Sounds (.mid/.sf2/.dls). The format is used in Crystal Dynamics games that were developed between 1994 to 2000.

SND

Header

There are three revisions, while no official name is given we have named them:

Name	Description
soul-reaver	The latest revision that can be found in later Crystal Dynamics games such as "Soul Reaver" and "Walt Disney's World Quest - Magical Racing Tour".
prototype	A revision that can be found in early prototypes of the game "Soul Reaver", but it's possible it can be found in other places as well.
gex	An old revision that can be found in early Crystal Dynamics games such as "Gex".

Read left to right, the magic number should always read "DNSa". After loading the header, the program uses the header size as an offset into the file's main body. However since the specification uses 4-byte alignment once a section has been loaded, the number in the header size must be adjusted. If the size is not a multiple of four, increase it to the next multiple of four.

Soul Reaver Header

Name	Type	Endianness
Magic number	ASCII character x4	N/A
Header size	Unsigned 32 bit integer	Little
Bank version	Unsigned 32 bit integer	Little
Number of programs	Unsigned 32 bit integer	Little
Number of zones	Unsigned 32 bit integer	Little
Number of waves	Unsigned 32 bit integer	Little
Number of sequences	Unsigned 32 bit integer	Little
Number of labels	Unsigned 32 bit integer	Little
Reverb mode	Unsigned 32 bit integer	Little
Reverb depth	Unsigned 32 bit integer	Little

Prototype Header

Name	Type	Endianness
Magic number	ASCII character x4	N/A
Header size	Unsigned 32 bit integer	Little
Bank version	Unsigned 16 bit integer	Little
Unknown	Unsigned 8 bit integer	N/A
Number of programs	Unsigned 8 bit integer	N/A
Number of zones	Unsigned 16 bit integer	Little
Number of waves	Unsigned 16 bit integer	Little
Number of sequences	Unsigned 16 bit integer	Little
Number of labels	Unsigned 16 bit integer	Little
Reverb mode	Unsigned 16 bit integer	Little
Reverb depth	Unsigned 16 bit integer	Little

Gex Header

Name	Type	Endianness
Magic number	ASCII character x4	N/A
Header size	Unsigned 16 bit integer	Little
Unknown	Unsigned 8 bit integer	N/A
Number of programs	Unsigned 8 bit integer	N/A
Number of zones	Unsigned 16 bit integer	Little
Number of waves	Unsigned 16 bit integer	Little
Number of sequences	Unsigned 16 bit integer	Little
Number of labels	Unsigned 16 bit integer	Little
Reverb mode	Unsigned 16 bit integer	Little
Reverb depth	Unsigned 16 bit integer	Little

Program Structure

The header specifies how many programs are present, this number cannot exceed 16. Each program has at most 16 zones associated with it. The volume can range from 0 to 127, with a default of 127. The panning has the same range of 0 to 127, but has a default of 64.

Name	Type	Endianness	Range	Default
Number of program zones	Unsigned 16 bit integer	Little	0 - 16
First zone	Unsigned 16 bit integer	Little
Program volume	Unsigned 8 bit integer	N/A	0 - 127	127
Program panning position	Unsigned 8 bit integer	N/A	0 - 127	64
Unused	Unsigned 16 bit integer	Little

A program can sometimes request more zones when there are no more left. In this case the program should be treated as if it has zero zones.

Zone Structure

The header also specifies the maximum zone count.

Banks are used to collect multiple instrument patches together, with each bank number being associated with a set of patches. This is a problem because the "Parent program" entry does not know this and only functions as a patch index. When this index returns to 0, it marks the beginning of a new bank.

Name	Type	Endianness	Range	Default
Priority	Unsigned 8 bit integer	Little
Parent program	Unsigned 8 bit integer	Little
Zone volume	Unsigned 8 bit integer	Little	0 - 127	127
Zone panning position	Unsigned 8 bit integer	Little	0 - 127	64
Root key	Unsigned 8 bit integer	Little	0 - 127	60
Pitch finetuning	Unsigned 8 bit integer	Little
Lowest key	Unsigned 8 bit integer	Little	0 - 127	127
Highest key	Unsigned 8 bit integer	Little	Lowest key - 127	127
Mode	Unsigned 8 bit integer	Little
Maximum pitch bending range	Unsigned 8 bit integer	Little
ADSR 1	Unsigned 16 bit integer	Little
ADSR 2	Unsigned 16 bit integer	Little
Wave index	Unsigned 16 bit integer	Little

Wave Offsets

These are the offsets to where the waves/samples are stored, the number is specified by the header. Sometimes these are relative, and sometimes absolute, to deal with this take the first offset from the list and subtract all other values from that to get an offset from the beginning of the list:

1200 -> 0000
1220 -> 0020
1235 -> 0035

The reason for the confusion is because the numbers sometimes refer to absolute memory addresses in the PlayStation's SPU buffer, rather than offsets into the file. The offsets are all relative to the beginning of the smp body, so make sure to load the smp header before using them.

Name	Type	Endianness
Wave offsets	Unsigned 32 bit integer array	Little

Sequence Offsets

The number of sequences is specified in the header. The offsets are relative to where the first sequence appears in the snd file; the first offset should always be 0.

Name	Type	Endianness
Sequence offsets	Unsigned 32 bit integer array	Little

Label Offsets

The number of labels is specified in the header, note the usage is currently a little unclear.

Name	Type	Endianness
Label offsets	Unsigned 32 bit integer array	Little

Sequences

After loading all of the label offsets you should arrive at the first sequence of the snd file, this is where the relative sequence offsets are used.

Each sequence can have two possible magic numbers:

• QESa, a "Type 0" sequence. When we export it we give it the extension cds, standing for "Crystal Dynamics Sequence". seq isn't used since it is already a real format used for PlayStation sequences.
• QSMa, a "Type 1" sequence. The extension msq is used which resembles the acronym found in the magic number.

After loading these, the snd file should be complete.

SMP

Sometimes the magic number is absent, you cannot tell ahead of time if it will be present, not even the SND revision will help with 100% certainty. If present the number should be "PMSa", if it is missing, use the first four bytes for the body size and continue with the header being only 4 bytes long.

If extracting from a PlayStation game, the body will contain Sony's proprietary ADPCM, also known as VAG or SONY_4BIT_ADPCM. If from another console you may find other codecs.

Name	Type	Endianness
Magic number	ASCII character x4	N/A
Body size	Unsigned 32 bit integer	Little

The body continues for the rest of the file after the header.