What is the DS2 file format?
Files saved with the .ds2 extension store audio data in the Digital Speech Standard Pro format. This method of voice recording, in its original version DSS, was developed by the Grundig company in 1994. Its improvement, known as DSS Pro, was created in collaboration between Olympus, Grundig, and Philips as part of the International Voice Association (IVA).
Capabilities of the DS2 Audio Format
The .ds2 files were developed with the aim of achieving an optimal format for recording voice - conversations or professional dictation. The format allows high compression combined with excellent quality. DSS Pro provides:
- optimal compression - file sizes up to 50 times smaller than an equivalent WAV recording
- optional data encryption via AES-128 or AES-256
- simple management in the selected work system
- fast file uploading or downloading
- easier file processing - splitting, merging, and overwriting segments
- reduced disk space for storage
Audio is sampled at 8,000 Hz in standard-play mode or up to 16,000 Hz in high-quality modes, keeping sound clear and intelligible for speech recognition systems.
Practical Use of DS2 Files
The .ds2 format is widely used on professional digital voice recorders. It is valued for its core functionality of recording high-quality sound, fast playback, and fast-forwarding. The DS2 format is also ideal for dictation workflows due to the simplicity of overwriting or inserting voice segments.
Olympus was acquired by OM Digital Solutions (OMDS) in 2021; support software including ODMS R7 is now distributed through audiosupport.omsystem.com. Third-party tools such as Express Scribe also support unencrypted .ds2 playback.
Security & safety
RISK: LOWDS2 is a dictation audio format - it contains no executable code or scripts. Files may be AES-128/256 encrypted by the sender's device/software, in which case you need the authorized Olympus ODMS software with the correct key to play them. No known malware vectors associated with this format.
Format details
in a nutshellPrograms that open DS2 files
Windows3 apps
Olympus DSS Player (ODMS R7)
Freemium Install DSS Player Standard (free) or ODMS R7 (professional); open or double-click the DS2 file.
Express Scribe Transcription Software
Freemium Load the DS2 file via File > Load Audio File or drag and drop; works for unencrypted DS2.
Bytescribe WavPlayer
Paid Open the DS2 file via File > Open; supports foot pedal control for transcription. 
macOS2 apps
Olympus ODMS R7 (macOS)
Freemium Use the macOS-compatible ODMS client; check omsystem.com for macOS availability. Technical details
deep spec| Audio codec | DSS Pro - proprietary high-compression speech codec; successor to the original DSS format |
| Sample rate | 8,000 Hz (SP standard-play mode); 12,000-16,000 Hz (QP/ST high-quality modes) |
| Channels | Mono - optimized for speech and dictation |
| Encryption | Optional AES-128 or AES-256; configurable per device or software profile |
| Typical file size | ~1 MB per hour of recording at standard quality; 500 KB - 2 MB per session |
| Container | Proprietary binary header block followed by compressed DSS Pro audio payload |
| Compression ratio | Up to ~50× smaller than equivalent WAV; ~4:1 vs uncompressed PCM speech |
| Header metadata | Recording date/time, duration, author ID, priority flag, encryption settings, device model |
| Platform support | Windows (primary); macOS via Olympus ODMS R7 (limited support) |
| Predecessor format | `.dss` - original DSS format (1994); DS2/DSS Pro adds AES encryption and improved audio quality |
| Developer consortium | International Voice Association (IVA) - Olympus, Philips, Grundig Business Systems |
| Current software distributor | OM Digital Solutions (OMDS), after acquiring Olympus in 2021; software at audiosupport.omsystem.com |
| Magic bytes | None publicly documented; identification relies on the `.ds2` extension and proprietary binary header structure |
| Released | circa 2003 (DSS Pro / DS2 generation; base DSS from 1994) |
| Latest version | DS2 / DSS Pro (current; supersedes original DSS) |
| Specification | audiosupport.omsystem.com |
DS2 conversions
Community Q&A
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