BSA File

What are BSA files and how to open them

Are you having problems opening a BSA 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 BSA files.

What is a BSA file?

BSA files have multiple uses, and BSArc Compressed Archive is one of them. Read more about the other uses further down the page.

BSArc Compressed Archive

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open BSA files

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

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

Last updated: August 25, 2026

All known file formats using extension .BSA

While BSArc Compressed Archive is a popular type of BSA-file, we know of 2 different uses of the .BSA file extension. Different software may use files with the same extension for different types of data.

The Bone Shaker Architect Music

The Bone Shaker Architect Music files store songs in a tracker-style format tailored for use in the Bone Shaker Architect audio tool, designed by Mario Knezovic. These files encode multi-track music using OPL synthesis (FM synthesis chip registers) including both melodic and percussion tracks. They are intended for composing and playing back synthetic music (e.g. game background tracks or chiptune-style pieces) with precise control over instrument parameters and pattern sequences.

Songs are produced in the Bone Shaker Architect application. The files list one or more patterns built from "pattern segments," arrange those patterns into an order list, and define instruments by their OPL register settings (attack/decay, sustain/release, vibrato, waveform selection etc.). When played, each track (channel) uses the defined instrument settings, following the order of pattern segments to render the full song. Support and tools exist for creating, editing, converting, and playing these files.

Files begin with the ASCII signature "TBSA0.01" at offset zero. The header following this includes pointers (little-endian 16-bit offsets) to tables for orders, instruments, patterns, and a few currently unused or unknown lists. Instruments are stored with multiple bytes encoding OPL operator settings; patterns are composed via event bytes that include commands for note-on, instrument select, row increments, volume, note-off, and end-of-track.

Various apps that use files with this extension

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

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about BSA file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.