What is the STS file format?
The .sts file is a tracker module produced by ScreamTracker 2, a DOS-based music sequencer released by the Finnish demo group Future Crew (primarily Sami Tammilehto, credited as "PSI") around 1990.
Like its sibling .MOD, a tracker module bundles both pattern/note data and the raw audio samples that drive playback. In .sts files, up to 15 instruments can be embedded as 8-bit PCM audio, arranged across up to 4 independent channels, with tempo expressed in BPM. The header begins with a 28-byte null-padded song title field; there are no distinct magic bytes to identify the format from binary structure alone.
The .sts format is closely related to .stm (the other ScreamTracker 2 module variant) and was superseded in 1994 by the S3M format, which ScreamTracker 3 introduced with 32-channel support, up to 100 instruments, and stereo output.
Today .sts files are encountered only in retro-computing and demoscene contexts. Modern tracker applications such as OpenMPT and Schism Tracker support playback and editing; the command-line player xmp (Extended Module Player) can also render them on current operating systems.
Security & safety
RISK: LOWSTS is a DOS-era audio module file with no executable content on modern systems. No known security risks; historical format.
Format details
in a nutshell- Generic status/settings file - Some applications use .sts as a generic extension for status or settings files; unrelated to tracker audio.
Programs that open STS files
Windows4 apps
Awave Studio
Paid File > Open to import the STS module; export samples or convert the song to WAV/MP3. 
VLC media player
Open-source Open the STS file in VLC (uses libmodplug internally); plays tracker modules directly. 
OpenMPT
Open-source File > Open the STS file to view the pattern editor and play back the module. Supports legacy MOD/STM/STS formats. 
Winamp (with in_mod plugin)
Free Winamp with the Nullsoft Module Decoder (in_mod) plugin plays STS/STM modules. 
macOS2 apps
Schism Tracker
Open-source Open the STS file to view the pattern editor and play back the legacy module. 
Linux2 apps
xmp (Extended Module Player)
Open-source xmp file.sts - command-line playback via libxmp, which supports STM/STS format. Technical details
deep spec| File encoding | Binary tracker module (flat binary, no container wrapper) |
| Byte order | Little-endian |
| Channels | Up to 4 (mono-based channel mixing) |
| Max instruments | 15 per module |
| Sample encoding | 8-bit PCM, unsigned; raw samples stored after pattern data |
| Max sample rate | Up to 22,050 Hz per instrument (defined in each instrument header) |
| Tempo | BPM-based; stored as a byte value in the module header |
| Header layout | Offset 0: 28-byte null-padded song title; followed by tempo, order list, and pattern count |
| Magic bytes | None; format identified by `.sts` extension and header context only |
| Compression | None - raw binary layout |
| Typical file size | 10 KB - 200 KB |
| Native OS | MS-DOS; playback on modern systems requires a tracker emulator or player |
| Released | 1990 (ScreamTracker 2.x) |
| Latest version | ScreamTracker 2.3 (final release circa 1992) |
| Specification | fileformats.archiveteam.org |
STS conversions
Community Q&A
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