Extract Audio from 3GPP to DSS — Free Online Tool
Extract audio from 3GPP mobile video files and convert it to DSS (Digital Speech Standard) format using the ADPCM IMA OKI codec — the same proprietary codec used by Olympus, Philips, and Grundig digital dictation devices. This is especially useful for transcribing voice recordings captured on mobile phones and replaying them on dedicated dictation hardware.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your 3GPP file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
3GPP files typically carry audio encoded as AAC or MP3 alongside a video stream. This tool strips the video entirely and re-encodes only the audio stream using the ADPCM IMA OKI codec required by the DSS format. Because AAC and ADPCM IMA OKI are fundamentally different compression schemes — AAC is a modern perceptual codec while ADPCM IMA OKI is a low-rate adaptive delta PCM variant optimized for speech — full re-encoding is unavoidable. The output is a fixed-rate, speech-optimized DSS file compatible with professional dictation workflows. No quality settings are exposed for DSS because the codec operates at a fixed bitrate dictated by the format specification.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that handles all decoding, re-encoding, and muxing for this conversion. |
-i input.3gp
|
Specifies the input 3GPP file. FFmpeg reads the container, detecting both the video stream (typically H.264) and the audio stream (typically AAC) inside the .3gp file. |
-vn
|
Disables video output entirely. Since DSS is a speech-only audio format with no video support, the H.264 or MJPEG video track from the 3GPP file is discarded and never written to the output. |
-c:a adpcm_ima_oki
|
Selects the ADPCM IMA OKI audio encoder, the only codec valid for the DSS format. This re-encodes the AAC audio from the 3GPP file into the fixed-rate ADPCM variant used by Olympus, Philips, and Grundig digital dictation devices. |
output.dss
|
Sets the output filename with the .dss extension, which instructs FFmpeg to use the DSS muxer and write a file compatible with professional dictation software and hardware. |
Common Use Cases
- A field worker records a voice memo or interview on a 3G-era mobile phone as a .3gp file and needs to load it into Olympus or Philips dictation software that only accepts DSS input.
- A legal transcription office receives 3GPP voice recordings from clients and must convert them to DSS so transcriptionists can use foot-pedal-controlled DSS players for playback.
- A medical professional dictates patient notes into a smartphone app that saves 3GPP files, then needs to import those notes into a DSS-based transcription system used by their practice.
- A journalist records a phone interview as a 3GPP video (common on older Android devices) and wants to extract just the spoken audio into a format compatible with legacy dictation hardware for review.
- An archivist is standardizing a collection of mobile voice recordings from the early 2000s into DSS format to match the dictation archives already stored in that format.
Frequently Asked Questions
Yes, some quality loss is expected, but for speech it is generally acceptable. Your 3GPP file's AAC audio is already lossy, and re-encoding it into ADPCM IMA OKI — a codec specifically tuned for human voice frequencies used in dictation — introduces a second generation of lossy compression. For music or complex audio this would be noticeable, but for spoken word recordings (the intended use case for DSS) the result is typically intelligible and usable for transcription purposes.
The DSS format using the ADPCM IMA OKI codec operates at a fixed bitrate defined by the format specification — there are no user-adjustable quality parameters. Unlike AAC (used in 3GPP files) which supports variable bitrates, ADPCM IMA OKI encodes at a constant rate, which is why no audio quality options appear for this conversion. The output file size is therefore entirely determined by the duration of the audio.
DSS files produced with the ADPCM IMA OKI codec should be recognized by most Olympus and Philips dictation software, as this codec is the foundation of the original DSS standard. However, both Olympus and Philips have released newer variants like DSS Pro (DS2), and some newer software versions have limited support for the original DSS codec. If your software does not accept the file, check whether it requires the DS2 format instead.
No. The DSS format is audio-only and has no mechanism to store video. The -vn flag in the FFmpeg command explicitly discards the video stream. Only the audio track from your 3GPP file is re-encoded and written to the DSS output. If you need to preserve the video, you should export it separately before running this conversion.
On Linux or macOS you can run a shell loop: for f in *.3gp; do ffmpeg -i "$f" -vn -c:a adpcm_ima_oki "${f%.3gp}.dss"; done. On Windows Command Prompt use: for %f in (*.3gp) do ffmpeg -i "%f" -vn -c:a adpcm_ima_oki "%~nf.dss". This applies the exact same conversion — stripping video and encoding audio with ADPCM IMA OKI — to every .3gp file in the current directory.
Very likely not. The DSS format has extremely limited metadata support compared to the MPEG-4 container used by 3GPP files, which can store rich metadata fields. FFmpeg will attempt to map any compatible tags, but most metadata from the 3GPP container — including creation timestamps and title fields — will be silently dropped during conversion to DSS. If preserving metadata is important, document it separately before converting.
Technical Notes
The DSS format was jointly developed by Olympus, Philips, and Grundig specifically for professional dictation and is not a general-purpose audio container. Its sole supported codec in FFmpeg is adpcm_ima_oki, a variant of Adaptive Differential Pulse-Code Modulation tuned for the narrow frequency range of human speech. The 3GPP container, by contrast, is a mobile-optimized MPEG-4 variant and typically contains AAC audio at 32–128 kbps. Because ADPCM IMA OKI is a much simpler codec with no perceptual modeling, it is markedly inferior for music or broadband audio, but performs reasonably well on speech in the 300–3400 Hz telephony band that dominates mobile voice recordings. One key limitation: FFmpeg's DSS muxer support is constrained to a specific sample rate (typically 8000 Hz); if your 3GPP audio is at a higher sample rate, FFmpeg will automatically resample it downward as part of the conversion. This resampling is another contributor to quality reduction but is unavoidable given the DSS specification.