CSMP (File Format)

The .CSMP file format is an audio format seen in Retro Studios games starting in Metroid Prime 3. It's very similar in use to AGSC and usually contains sound affects. Where CSMP differs is the fact that it only contains one sound and is broken up into obvious data chunks with easily identifiable sizes.

GravitySuitIcon.png To do:
Notate Tropical Freeze differences.


CSMP files are made up of a number of data chunks. Since not every file always has every chunk, the best way to read a CSMP file is to use a while loop to check the chunk headers and parse their contents until you reach the end of the file.


This is the header structure found in Metroid Prime 3 and Donkey Kong Country Returns; Tropical Freeze's is a bit different.

Offset Size Description
0x0 4 "CSMP" magic fourCC
0x4 4 Version; always 1

Chunk Header

Every chunk begins with this header; it contains a brief data type identifier and a size.

Offset Size Description
0x0 4 Chunk type fourCC
0x4 4 Chunk size (N)
0x8+N End of chunk


This chunk just has a null-terminated string; it's the name of the contained sound data.


Offset Size Description
0x0 1 Unknown
0x1 1 Loop Flag
0x2 4 Unknown
0x6 2 Unknown
0x8 4 Volume


This chunk is just padded with 0xFF; usually contains 0x14 bytes.


The DATA section essentially just embeds a standard DSP, including the full header and ADPCM audio data. Refer to the DSP page for details. Note that for some reason, the DATA chunk is always 4 bytes smaller than its size indicates.