Convert 3G2 to VOC — Free Online Tool
Convert 3G2 mobile video files to VOC audio format, extracting and re-encoding the audio stream to unsigned 8-bit PCM — the raw, uncompressed format used by Creative Labs Sound Blaster cards in classic DOS applications. This tool strips the video and any AAC or MP3 audio from the 3G2 container and outputs a retro-compatible VOC file entirely in your browser.
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FFmpeg Command
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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
A 3G2 file typically contains a video stream (H.264) and a compressed audio stream (most commonly AAC). During this conversion, FFmpeg discards the video stream entirely and decodes the AAC audio to raw PCM samples, then re-encodes those samples as unsigned 8-bit PCM (pcm_u8) — the native audio encoding of the VOC format. This is a full audio transcode, not a remux: the compressed audio data is decoded and rewritten as uncompressed 8-bit samples at the source file's sample rate. The VOC container itself is a simple, headerless-style format from the Sound Blaster era, so no metadata, chapters, or multiple audio tracks from the 3G2 source will be preserved.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which handles all demuxing, decoding, re-encoding, and muxing for this 3G2-to-VOC conversion entirely on your local machine. |
-i input.3g2
|
Specifies the input file — a 3G2 container carrying CDMA mobile video and audio. FFmpeg will parse the MP4-derivative container structure and expose both the H.264 video and AAC audio streams for processing. |
-c:a pcm_u8
|
Sets the audio codec to unsigned 8-bit PCM, which is the native and most broadly compatible encoding for VOC files. This causes FFmpeg to fully decode the AAC audio from the 3G2 and re-encode every sample as an 8-bit unsigned integer — the raw format Sound Blaster hardware reads directly. |
output.voc
|
Defines the output file with a .voc extension, which causes FFmpeg to use the VOC muxer and write a Creative Labs VOC-format file. The video stream from the 3G2 source is automatically dropped since the VOC format is audio-only. |
Common Use Cases
- Extracting voice recordings or audio clips from old 3G2 videos captured on a CDMA phone and importing them into a retro DOS game or Sound Blaster-compatible application as VOC sound effects.
- Game modders working on classic DOS titles (such as games using iD Software or Westwood Studios engines) who need to replace or add custom sound effects and require VOC-format source audio from modern mobile recordings.
- Retro computing enthusiasts running DOSBox who want to use audio from 3G2 mobile clips as in-game sounds, since DOSBox natively supports VOC playback through its Sound Blaster emulation.
- Archivists converting 3G2 audio content to an uncompressed PCM-based VOC file to eliminate AAC codec dependency and store audio in a format readable by legacy audio tools without modern codec libraries.
- Developers building or testing Sound Blaster emulation layers who need real-world audio samples in VOC format and are sourcing them from mobile device recordings stored as 3G2 files.
- Audio educators or hobbyists demonstrating the quality difference between modern lossy mobile audio (AAC in 3G2) and the 8-bit unsigned PCM audio of the Sound Blaster era by producing a direct comparison VOC file.
Frequently Asked Questions
Yes, in a nuanced way. The 3G2 file's AAC audio is decoded to full PCM during the conversion, but then stored as 8-bit unsigned PCM (pcm_u8) in the VOC file. 8-bit PCM has a dynamic range of only 48 dB, compared to the 96 dB of 16-bit audio, which means the output will sound noticeably noisier and flatter than the source — this is an inherent characteristic of the VOC format's most common encoding, not a flaw in the conversion process itself.
By default, FFmpeg will carry the source sample rate into the VOC output, but VOC format has historical limitations around supported sample rates tied to Sound Blaster hardware (typically 8000 Hz to 44100 Hz). If your 3G2 audio was recorded at an unusual rate, you may want to explicitly set the output sample rate using -ar 22050 or -ar 44100 in the command to ensure compatibility with the target DOS application or emulator.
Yes. VOC format supports 16-bit signed little-endian PCM (pcm_s16le) in addition to 8-bit unsigned PCM. To use it, change the command to: ffmpeg -i input.3g2 -c:a pcm_s16le output.voc. The resulting file will have significantly better dynamic range and less quantization noise, though compatibility with very old Sound Blaster hardware or certain DOS game engines may be reduced since not all VOC readers support 16-bit samples.
VOC stores audio as raw uncompressed PCM, so there is no bitrate parameter to adjust — every sample is stored directly without compression. The file size and fidelity are determined solely by the sample rate and bit depth (8-bit or 16-bit). This is fundamentally different from the AAC audio in your source 3G2 file, which uses perceptual compression to reduce file size at the cost of some audio detail.
You can use a shell loop to batch process files. On Linux or macOS: for f in *.3g2; do ffmpeg -i "$f" -c:a pcm_u8 "${f%.3g2}.voc"; done. On Windows Command Prompt: for %f in (*.3g2) do ffmpeg -i "%f" -c:a pcm_u8 "%~nf.voc". This will process every 3G2 file in the current directory and produce a matching VOC file, which is especially useful when pulling audio from a batch of old CDMA mobile recordings.
The video stream — typically H.264 encoded — is completely discarded. FFmpeg detects that the VOC output format is audio-only and automatically drops all video data without requiring an explicit -vn flag. Only the audio content from the 3G2 file is decoded and written to the VOC output, making the output file much smaller and containing no visual information.
Technical Notes
The 3G2 container is a close relative of MP4/MOV, built on the MPEG-4 Part 12 base format for CDMA mobile networks, and typically carries H.264 video alongside AAC audio at low bitrates suited for CDMA transmission. VOC, by contrast, is a mid-1990s Creative Labs format designed around the hardware constraints of the Sound Blaster ISA card. The pcm_u8 codec used in this conversion stores audio as 8-bit unsigned integers centered at 128, giving a theoretical dynamic range of roughly 48 dB — far below the AAC source, which despite being lossy can represent much finer amplitude gradations. No metadata from the 3G2 file (such as recording date, GPS tags, or track titles) will survive in the VOC output, as the VOC format has no standardized metadata block support. The VOC format also does not support stereo in its most basic form on original hardware, though modern VOC readers and DOSBox handle stereo pcm_u8 correctly. If strict mono compatibility is needed, add -ac 1 to the FFmpeg command to downmix to mono before encoding.