BKM File

What are BKM files and how to open them

Are you having problems opening a BKM file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BKM files.

What is a BKM file?

A .BKM file is a BizHawk Movie Capture file.

BizHawk's original movie capture format stores a complete recording of user inputs (and certain metadata) for a gameplay session under BizHawk's Tool-Assisted Speedrun (TAS) system. It was used for live or TAS-style gameplay where input per frame needed preserving exactly, including rerecords, resets, the game ROM identity, platform, and game version information. The format ensures deterministic playback so the same inputs with the same emulator version, core, rom, and firmware reproduce the same outcome.

The format is produced and consumed by the BizHawk emulator (versions up through 1.7.1). It represents movies in plain UTF-8 text: one section for the header metadata, followed by frame-by-frame input data. Headers include fields such as emu version, movie version, platform, game name, author name, rerecord count, GUID, savestate start flag, and alerts to whether PAL mode, firmware SHA1, and mapper or board settings were used. After the header, a frame-by-frame input log records which buttons or controls were actuated each frame. The format supports optional subtitles and loop-offset fields for infinite loops. Because it is text, it can be viewed and edited with a plain text editor, but changes risk breaking playback if not done correctly.

Internally the file begins with an ASCII signature "emuVersionVersion" at offset zero, includes the string "MOVIEVERSION BIZHAWK V" shortly thereafter, and contains distinct tokens / field labels like "RERECORDCOUNT", "GAMENAME", "PLATFORM", "AUTHOR", and "SHA1" to mark key metadata entries.

How to open BKM files

Important: Different programs may use files with the BKM file extension for different purposes, so unless you are sure which format your BKM file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested five different BKM openers which you will find listed below.

Last updated: August 24, 2026

Various apps that use files with this extension

These apps are known to open certain types of BKM files. Remember, different programs may use BKM files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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