mmv is the movie capture format of Dega, a Sega Master System emulator.
Header format:
0000: 4-byte signature: "MMV\0"
0004: 4-byte little endian unsigned int: dega version
0008: 4-byte little endian unsigned int: frame count
000c: 4-byte little endian unsigned int: rerecord count
0010: 4-byte little endian flag: begin from reset?
0014: 4-byte little endian unsigned int: offset of state information
0018: 4-byte little endian unsigned int: offset of input data
001c: 4-byte little endian unsigned int: size of input packet
0020-005f: string: author info (UTF-8)
0060: 4-byte little endian flags
bit 0: unused
bit 1: PAL
bit 2: Japan
bit 3: Game Gear (version 1.16+)
bits 4-31: unused
0064-00e3: string: rom name (ASCII)
00e4-00f3: binary: rom MD5 digest
Controller data format
Controller data is made up of one input packet per frame. Each packet currently consists of 2 bytes. The first byte is for controller 1 and the second controller 2. The Game Gear only uses the controller 1 input however both bytes are still present. The bit layout is:
76543210 bit 0 (0x01): up bit 1 (0x02): down bit 2 (0x04): left bit 3 (0x08): right bit 4 (0x10): 1 bit 5 (0x20): 2 bit 6 (0x40): start (Master System) bit 7 (0x80): start (Game Gear)
On the Master System bit 6 (0x40) will only be set for one frame when the button is depressed.
See also: Emulator homepages, frequently asked questions