Extract Audio from 3GP to VOC — Free Online Tool
Extract audio from 3GP mobile video files and save it as a VOC file using lossless PCM encoding. This tool strips the AAC or MP3 audio track from your 3GP container and re-encodes it to 8-bit unsigned PCM — the raw audio format used by Creative Labs Sound Blaster cards — making it compatible with classic DOS games and retro audio toolchains.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
3GP files store audio in compressed lossy codecs — typically AAC at low bitrates (commonly 64k) optimized for 3G mobile networks. During this conversion, FFmpeg discards the video stream entirely and decodes the compressed audio from the 3GP container, then re-encodes it to PCM unsigned 8-bit (pcm_u8), which is the native codec of the VOC format. This means the audio is fully decoded from its compressed mobile-optimized form and re-encoded as raw, uncompressed 8-bit PCM samples. Because AAC is a lossy codec, some quality was already lost when the 3GP was created — the VOC output faithfully preserves whatever fidelity the source audio contained, but cannot recover what AAC compression discarded. The resulting VOC file will be significantly larger than the source 3GP audio due to the shift from compressed to raw uncompressed PCM.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program. In the browser-based tool, this runs as FFmpeg.wasm compiled to WebAssembly, executing entirely within your browser with no server involvement. On your desktop, this calls your locally installed FFmpeg binary. |
-i input.3gp
|
Specifies the input file — a 3GP container, the multimedia format defined by the Third Generation Partnership Project for 3G mobile phones. FFmpeg will read the file's video and audio streams from this container, which typically holds H.264 video and AAC audio. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the H.264 video stream in the 3GP file. Since we are extracting audio only for a VOC file (which is audio-only), the video track is discarded without being decoded, saving processing time. |
-c:a pcm_u8
|
Sets the audio codec to PCM unsigned 8-bit, which is the native and most compatible codec for the VOC format. This decodes the compressed AAC audio from the 3GP file and re-encodes it as raw 8-bit uncompressed samples, matching the encoding expected by Sound Blaster hardware and classic DOS software. |
output.voc
|
Specifies the output filename with the .voc extension, which tells FFmpeg to write the result in the Creative Labs VOC container format. The VOC container wraps the pcm_u8 audio data with a simple header block that identifies sample rate, bit depth, and channel count for playback by Sound Blaster-compatible applications. |
Common Use Cases
- Importing voice recordings or sound effects from old mobile phone 3GP files into a classic DOS game engine or retro game development tool that requires VOC-format audio
- Archiving audio captured on early 2000s 3G mobile phones into VOC format for use in period-accurate multimedia preservation projects
- Extracting speech or sound clips from 3GP video files to use as samples in vintage tracker music software or Sound Blaster-compatible applications
- Converting mobile-recorded audio to VOC for use in DOSBox environments where VOC is the expected audio format for custom sound assets
- Stripping audio from short 3GP clips recorded on older Nokia or Motorola handsets to feed into retro audio editors that natively read VOC files
- Preparing mobile-sourced audio content for integration into legacy multimedia CD-ROM projects that were originally authored around Creative Labs VOC assets
Frequently Asked Questions
No — the audio quality is bounded by whatever the 3GP file already contains. 3GP typically stores audio in AAC at low bitrates like 64kbps, which is a lossy format designed for constrained 3G mobile bandwidth. Converting to VOC re-encodes that already-lossy audio as uncompressed 8-bit PCM, but the distortion and frequency cutoffs introduced during the original AAC encoding cannot be recovered. The VOC file will be larger and uncompressed, but it will not sound better than the source 3GP.
3GP compresses audio using AAC, which can achieve high compression ratios — a 64kbps AAC stream is a tiny fraction of the data that raw PCM requires. VOC stores audio as uncompressed 8-bit PCM samples, meaning every sample is stored as a raw byte with no compression. For example, a mono audio stream at 8kHz in 8-bit PCM uses 8,000 bytes per second, whereas the equivalent AAC stream might use only 8,000 bits (1,000 bytes) per second. The size increase is expected and is a normal property of moving from a compressed to an uncompressed audio format.
The default command uses pcm_u8 (8-bit unsigned PCM), which is the original Sound Blaster VOC format and required by most legacy DOS applications and game engines that load VOC files. If you are using a more modern tool that can handle VOC files with 16-bit audio, you can modify the FFmpeg command to use -c:a pcm_s16le, which will produce higher fidelity output with a greater dynamic range. However, for maximum compatibility with period-accurate DOS software and DOSBox, pcm_u8 is the correct choice.
No — the -vn flag in the FFmpeg command explicitly instructs FFmpeg to ignore the video stream entirely. The 3GP video, which is typically encoded with H.264 (libx264) at low resolution for mobile display, is discarded and never processed. Only the audio track is decoded and written to the VOC output file. This also means the conversion is fast, as no video decoding or encoding occurs.
You can append -ar and -ac flags to the command before the output filename to control the sample rate and number of channels. For example, to force mono output at 8kHz — which is standard for classic VOC files — you would use: ffmpeg -i input.3gp -vn -c:a pcm_u8 -ar 8000 -ac 1 output.voc. Many legacy DOS applications and Sound Blaster tools expect mono 8kHz or 11kHz audio in VOC files, so specifying these explicitly ensures maximum compatibility.
Yes — on Linux or macOS you can use a shell loop: for f in *.3gp; do ffmpeg -i "$f" -vn -c:a pcm_u8 "${f%.3gp}.voc"; done. On Windows Command Prompt you would use: for %f in (*.3gp) do ffmpeg -i "%f" -vn -c:a pcm_u8 "%~nf.voc". The browser-based tool processes one file at a time, but the FFmpeg command shown on this page can be run locally on your desktop for batch processing of large collections of 3GP files, with no file size limit.
Technical Notes
VOC is a simple, header-based container with no support for metadata tags — artist, title, album, and any other ID3 or similar tags present in the 3GP file will be silently dropped during conversion. The VOC format supports a maximum of 8-bit (pcm_u8) or 16-bit (pcm_s16le) uncompressed PCM audio, meaning the dynamic range of the output is limited to either 48dB (8-bit) or 96dB (16-bit), compared to the perceptual quality of AAC which can sound cleaner at equivalent bitrates due to psychoacoustic modeling. 3GP files created by mobile phones often contain mono audio sampled at 8kHz or 16kHz; FFmpeg will preserve whatever sample rate is in the source unless explicitly overridden with -ar. VOC does not support multiple audio tracks, chapters, or subtitles — none of which 3GP typically carries either, so no functional data beyond the audio waveform is lost. Because both formats lack transparency and subtitle support, there are no edge cases around those features. The one meaningful quality concern is the 8-bit depth of pcm_u8: if the source 3GP audio is at a higher effective quality, the downsampling to 8-bit will introduce quantization noise audible on headphones, particularly in quiet passages.