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Emulator Resources / Gens / GMV

.gmv is the movie capture format of Gens, a Sega Genesis/Megadrive emulator.

GMV file format description

GMV file consists of a 64-byte header and the movie data.

Header format

  000 16-byte signature and format version: "Gens Movie TEST9"
  00F ASCII-encoded GMV file format version. The most recent is 'A'. (?)
  010 4-byte little-endian unsigned int: rerecord count
  014 ASCII-encoded controller config for player 1. '3' or '6'.
  015 ASCII-encoded controller config for player 2. '3' or '6'.
  016 special flags (Version A and up only):
     bit 7(most significant): if "1", movie runs at 50 frames per second; if "0", movie runs at 60 frames per second
     bit 6: if "1", movie requires a savestate.
     bit 5: if "1", movie is 3-player movie; if "0", movie is 2-player movie
  018 40-byte zero-terminated ASCII movie name string
  040 frame data

Controller Data

Each frame consists of 3 bytes.

000 001 002
Controller 1 Controller 2 *

where * is controller 3 if a 3-player movie, or XYZ-mode if a 2-player movie.

For controller bytes, each value is determined by OR-ing together values for whichever of the following are left unpressed:

   0x01 Up
   0x02 Down
   0x04 Left
   0x08 Right
   0x10 A
   0x20 B
   0x40 C
   0x80 Start

For XYZ-mode, each value is determined by OR-ing together values for whichever of the following are left unpressed:

   0x01 Controller 1 X
   0x02 Controller 1 Y
   0x04 Controller 1 Z
   0x08 Controller 1 Mode
   0x10 Controller 2 X
   0x20 Controller 2 Y
   0x40 Controller 2 Z
   0x80 Controller 2 Mode
The file has no terminator byte or frame count. The number of frames is the <filesize minus 64> divided by 3.

The file format has no means of identifying NTSC/PAL, but the FPS can still be derived from the header.



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EmulatorResources/Gens/GMV last edited by feos on 2016-03-19 10:12:42
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