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 text based by default; 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 consists of two parts: Header and Input Log.
The header is always in ASCII plain text format. It consists of several key-value pairs.
The input log section can be identified by it starting with a | (pipe).
The input log section can be either in ASCII plain text format or in binary format.
The input log section terminates at EOF, unless the length key is specified in header.
Newlines may be \r\n or \n.

Header

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 does 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 for true and 0 for false) must have a value that can be stored as int32:

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
NewPPU (bool) (optional) - true if the movie uses New PPU
FDS (bool) (optional) - true if the movie was recorded on a Famicom Disk System (FDS) game
fourscore (bool) true if a fourscore was used. If fourscore is not used, then port0 and port1 are required
port0 - indicates the type of input device attached to the port 0. Supported values are:
- SI_NONE = 0
- SI_GAMEPAD = 1
- SI_ZAPPER = 2
port1 - indicates the type of input device attached to the port 1. Supported values are:
- SI_NONE = 0
- 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
binary (bool) (optional) - true if input log is stored in binary format
length (optional) - movie size (number of frames in the input log). If this key is specified and the number is >= 0, the input log ends after specified number of records, and any remaining data should not be parsed. This key is used in fm3 format to allow storing extra data after the end of input log

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 should have their ordering preserved and may be used to approximate multi-line comments
- by convention, the author of the movie should be stored in comment(s) with a subject of: author
- example:
  - comment author adelikat
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 begin with the word "subtitle"
- by convention, an integer value following the word "subtitle" indicates the frame that the subtitle will be displayed
- by convention, any remaining text after the integer is considered to be the string displayed
- example:
  - subtitle 1000 Level Two
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
romChecksum (required) - the base64 of the hexified MD5 hash of the ROM which was used to record the movie (don't ask)
savestate (optional) - a fcs savestate blob, in case a movie was recorded from savestate

Inputlog

The input log section consists of movie records either in the form of text lines or in the form of binary data.

Text format (default format):

Every frame of the movie is represented by line of text beginning and ending with a | (pipe).
The fields in the line are as follows, except when fourscore is used.

commands

port0

port1

port2

Field commands is a variable length decimal integer which is interpreted as a bit field corresponding to miscellaneous input states which are valid at the start of the frame. Current values for this are:

1 = Soft Reset
2 = Hard Reset (Power)
4 = FDS Disk Insert
8 = FDS Disk Select
16 = VS Insert Coin

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 bit field
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:

YYY:

SIFC_NONE

the field must be empty

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

The input types must all be gamepads, and each input log record must be in the following format:

commands

RLDUTSBA

port2

{commands, player1, player2, player3, player4, port2}

Binary format:

Input log section starts with a | (pipe).
Every frame of the movie is represented by a record of a fixed length which can be determined by the devices on port0 and port1.

The first byte of each record stores "commands" bit field.

bit 0 = Soft Reset
bit 1 = Hard Reset (Power)
bit 2 = FDS Disk Insert
bit 3 = FDS Disk Select
bit 4 = VS Insert Coin

The remaining bytes in the record depend on which types of devices are attached to port0 and port1.

SI_GAMEPAD

1 byte added to the size of record
bits of the byte represent the state of buttons (bit0 = A, bit1 = B, bit2 = Select, bit3 = sTart, bit4 = Up, bit5 = Down, bit6 = Left, bit7 = Right). If the bit is set, respective button is considered to be pressed, if the bit is clear, the button is not pressed

SI_ZAPPER

12 bytes added to the size of record
1st byte - the x position of the mouse
2nd byte - the y position of the mouse
3rd byte - 1 if the mouse button is pressed; 0 if not
4th byte - an internal value used by the emulator's zapper code
bytes 5-12 (uint64) - an internal value used by the emulator's zapper code

SIFC_NONE

0 bytes added to the size of record

If a fourscore is used, then port0 and port1 are irrelevant and ignored. 4 bytes are added to the size of record. The bits of the 1st byte represent the state of buttons of the 1st joypad (bit0 = A, bit1 = B, bit2 = Select, bit3 = sTart, bit4 = Up, bit5 = Down, bit6 = Left, bit7 = Right); bits of the 2nd byte represent the state of buttons of the 2nd joypad, and so on.

Notes

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

The emulator uses these framerate constants:

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