Bay 12 CMV

• Company: Bay 12 Games
• Extension: cmv, ccmv
• Specifications:
  • Rough specification
  • C# example code
• Samples:
  • Movies - DF Map Archive (download links for each are in a box on the bottom left)

The CMV file format is used by the game Dwarf Fortress to store intro movies and player recordings.

File structure

Header

Type	Name	Description
uint32	Version	The format version used; should be >= 10000
uint32	Width	Width (in characters) of each frame
uint32	Height	Height (in characters) of each frame
uint32	DelayRate	How long each frame is displayed; seems to be in hundredths of a second.

Sounds

Sound data is present in version 10001 files, but not in 10000 or 10005.

Type	Name	Description
uint32	SoundCount	Number of sound references defined.
char[50]*SoundCount	SoundName	Filename (no dir or ext) of an external file which contains the sound data.

Sound timing data

An array of 3200 (16 channels x 200 frames?) 32-bit signed integers, each specifying an index into the array of sound refs defined above. An index of -1 indicates that no new sound is played at that point.

Frame data

Frame data is stored in zlib-compressed chunks containing a maximum of 200 frames:

Type	Name	Description
uint32	z_size	Size of compressed data.
bytes	z_data	z_size bytes of compressed data.

The uncompressed structure of each frame roughly corresponds to a text-mode screen buffer:

Type	Name	Description
char[Width*Height]	Characters	An array of characters, encoded in the CP437 character set.
char[Width*Height]	Attributes	Encodes the ANSI color codes for each character.

Note that the encoding of color attributes is nonstandard:

0ibbbfff
i   - Foreground Intensity Bit
bbb - Background Color Bits
fff - Foreground Color Bits

Related software

CMV Movie Editor