FM2 Movie file format

FM2 is the movie capture format of FCEUX

FM2 file format description

FCEUX uses a new movie file format - .fm2

This differs from the previous FCE Ultra movie format (.fcm) in the following ways:

• It is completely text based; allowing easy movie editing/splicing
• An imbedded GUID so FCEUX can tell if a savestate belongs to a particular movie file
• Movies recorded from Start (Power-on) no longer have a redundant savestate
• Contains mouse input for recording the Zapper and Arkanoid Paddle input

Format

FM2 is ASCII plain text. It consists of several key-value pairs followed by an inputlog section.

The inputlog section can be identified by its starting with a | (pipe). The inputlog section terminates at eof. Newlines may be \r\n or \n

Key-value pairs consist of a key identifier, followed by a space separator, followed by the value text. Value text is always terminated by a newline, which the value text will not include. The value text is parsed differently depending on the type of the key. The key-value pairs may be in any order, except that the first key must be version.

Integer keys (also used for Booleans, with a 1 or 0) will have a value that is a simple integer not to exceed 32bits

• version (required) - the version of the movie file format; for now it is always 3
• emuVersion (required) - the version of the emulator used to produce the movie
• rerecordCount (optional) - the rerecord count
• palFlag (bool) (optional) - true if the movie uses pal timing
• fourscore (bool) (*note C) - true if a fourscore was used
• FDS (bool) (optional) - true if the movie was recording on a Famicom Disk System (FDS) game
• port0, port1 (*note C) - indicates the types of input devices. Supported values are:
  • SI_GAMEPAD = 1
  • SI_ZAPPER = 2
• port2 (required) - indicates the type of the FCExp port device which was attached. Supported values are:
  • SIFC_NONE = 0

Header

String keys have values that consist of the remainder of the key-value pair line. As a consequence, string values cannot contain newlines.

• romFilename (required) - the name of the file used to record the movie
• comment (optional) - simply a memo.
  • by convention, the first token in the comment value is the subject of the comment.
  • by convention, subsequent comments with the same subject will have their ordering preserved and may be used to approximate multiline comments.
  • by convention, the author of the movie should be stored in comment(s) with a subject of: author
• subtitle (optional) - a message that will be displayed on screen when movie is played back (unless Subtitles are turned off, see Movie options).
  • by convention, subtitles will begin with the word subtitle
  • by convention, an integer value will proceed which will indicate the frame that the subtitle will be displayed
  • by convention, a string of text will follow which will be the string displayed
  • example:
    • subtitle 1000 Level Two
    • At frame 1000 the words "Level Two" will be displayed on the screen

Hex string keys (used for binary blobs) will have a value that is like 0x0123456789ABCDEF...

• romChecksum (required) - the MD5 hash of the ROM which was used to record the movie
• savestate (optional) - a fcs savestate blob, in case a movie was recorded from savestate

GUID keys have a value which is in the standard GUID format: 452DE2C3-EF43-2FA9-77AC-0677FC51543B

• GUID (required) a unique identifier for a movie, generated when the movie is created, which is used when loading a savestate to make sure it belongs to the current movie.

Inputlog

The inputlog section consists of lines beginning and ending with a | (pipe). The fields are as follows, except as noted in note C.

Field c is a variable length decimal integer which is a bitfield corresponding to miscellaneous input states which are valid at the start of the frame. Current values for this are

• MOVIECMD_RESET = 1

The format of port0, port1, port2 depends on which types of devices were attached.

SI_GAMEPAD

• the field consists of eight characters which constitute a bitfield.
• any character other than ' ' or '.' means that the button was pressed. By convention, the following mnemonics will be used in a column to remind us of which button corresponds to which column:
  • RLDUTSBA (Right,Left,Down,Up,sTart,Select,B,A)

SI_ZAPPER

• XXX YYY B Q Z
• XXX: %03d, the x position of the mouse
• YYY: %03d, the y position of the mouse
• B: %1d, 1 if the mouse button is pressed; 0 if not
• Q: %1d, an internal value used by the emulator's zapper code (this is most unfortunate..)
• Z: %d, a variable-length decimal integer; an internal value used by the emulator's zapper code (this is even more unfortunate..)

SIFC_NONE

• this field must always be empty

Notes

There is no key-value pair that indicates the length of the movie. This must be read by scanning the inputlog and counting the number of lines.

All movies start from power-on, unless a savestate key-value is present

If a fourscore is used, then port0 and port1 are irrelevant and ignored

If fourscore, the input types must all be gamepads

If fourscore is not used, then port0 and port1 are required

Emulator framerate constants

FCEUX uses these framerate constants:

• NTSC: 1008307711 /256/65536 = 60.099822938442230224609375
• PAL : 838977920 /256/65536 = 50.00698089599609375