Extract Audio from 3G2 to FLAC — Free Online Tool
Extract audio from 3G2 mobile video files and save it as lossless FLAC — perfect for archiving audio originally encoded with AAC in the 3GPP2 container. The extracted audio is re-encoded using the FLAC codec, preserving maximum quality without lossy compression artifacts.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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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
3G2 files are multimedia containers developed for CDMA mobile networks (like those used by Verizon and Sprint), typically carrying AAC or MP3 audio alongside H.264 video. This tool strips the video stream entirely and re-encodes the audio track — most likely AAC — into FLAC, a lossless format. Because the source AAC audio is lossy, the FLAC output captures every bit of the decoded AAC signal without introducing any additional quality loss from a second lossy encode. FLAC's lossless compression then stores that audio as efficiently as possible. The video stream is discarded, meaning the output file contains only audio.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg multimedia processing engine. This is the same underlying library running in your browser via WebAssembly (FFmpeg.wasm) that powers this tool. |
-i input.3g2
|
Specifies the input file — a 3G2 container formatted for 3GPP2/CDMA mobile standards, typically containing an H.264 video stream and an AAC or MP3 audio stream. |
-vn
|
Disables video output entirely, instructing FFmpeg to ignore the H.264 (or MJPEG) video stream in the 3G2 file. This is required because FLAC is a pure audio format and cannot contain a video stream. |
-c:a flac
|
Sets the audio codec to FLAC (Free Lossless Audio Codec). FFmpeg will fully decode the AAC audio from the 3G2 container and re-encode it as lossless FLAC, ensuring no additional quality loss beyond what the original AAC compression introduced. |
-compression_level 5
|
Sets FLAC's compression effort to level 5 (the codec's default, on a 0–8 scale). This controls only the file size and encoding speed — all levels produce bit-identical audio. Level 5 is a balanced choice for typical short 3G2 recordings from mobile devices. |
output.flac
|
The output filename with a .flac extension, telling FFmpeg to write a standalone FLAC audio file containing the extracted and losslessly re-encoded audio from the original 3G2 source. |
Common Use Cases
- Archiving audio from old 3G2 video clips recorded on CDMA phones (e.g., older Verizon or Sprint handsets) in a high-fidelity format that won't degrade further over time
- Extracting voice memos, interviews, or field recordings captured as 3G2 video to FLAC for professional audio editing in a DAW like Audacity or Adobe Audition
- Recovering audio from 3G2 multimedia messages (MMS) or carrier-delivered content and preserving it in a lossless archive format
- Preparing audio from 3G2 clips for music or audio production workflows that require lossless source files to avoid generational quality loss during processing
- Converting a library of legacy 3G2 mobile recordings to FLAC for long-term digital archiving on NAS drives or cloud storage with lossless fidelity
- Extracting a spoken-word or ambient audio track from a 3G2 file to use in a podcast or video project where re-encoding to AAC or MP3 would introduce a second round of lossy compression
Frequently Asked Questions
No — FLAC is lossless, but it cannot recover quality that was already lost when the audio was originally encoded as AAC inside the 3G2 container. What FLAC guarantees is that the decoded AAC signal is preserved bit-for-bit without any further quality degradation. This makes FLAC the ideal archive format: if you later need to convert to MP3 or Opus, you'll be re-encoding from the best possible version of the audio rather than compounding lossy artifacts.
3G2 files are designed for low-bandwidth CDMA mobile networks, so both the video (H.264) and audio (AAC) are heavily compressed with lossy codecs at low bitrates. FLAC uses lossless compression, which preserves the full decoded audio signal — meaning the audio-only FLAC output can easily be several times larger than the audio portion of the original 3G2, even though the video has been removed. This is expected and is the trade-off for guaranteed lossless archival quality.
FLAC supports rich metadata through Vorbis Comment tags (fields like TITLE, ARTIST, ALBUM, DATE, etc.), but 3G2 files use MPEG-4-style metadata atoms which are structured differently. FFmpeg will attempt to map compatible metadata fields during conversion, but some 3G2-specific or carrier-inserted tags may not transfer cleanly. You should verify and edit the FLAC tags after conversion using a tool like fre:ac, MusicBrainz Picard, or Kid3.
The -compression_level flag controls how hard the FLAC encoder works to reduce file size, on a scale from 0 (fastest, least compressed) to 8 (slowest, most compressed). Crucially, all levels produce bit-identical audio — only the file size and encoding speed differ. Level 5 is the FLAC default and offers a well-balanced trade-off. For 3G2 files, which typically have short durations and low-bitrate audio, the difference in file size between levels is often negligible, so level 5 is a sensible choice for most users.
Yes. On Linux or macOS, you can run a shell loop: `for f in *.3g2; do ffmpeg -i "$f" -vn -c:a flac -compression_level 5 "${f%.3g2}.flac"; done`. On Windows Command Prompt, use: `for %f in (*.3g2) do ffmpeg -i "%f" -vn -c:a flac -compression_level 5 "%~nf.flac"`. This applies the exact same conversion to every 3G2 file in the current directory. Note that this browser-based tool processes one file at a time; the FFmpeg command is provided for desktop batch use, especially for collections exceeding 1GB per file.
Yes. While AAC is the default audio codec in 3G2 files, some 3G2 containers carry MP3 (libmp3lame-encoded) audio. FFmpeg will automatically detect the audio codec in your specific file and decode it correctly before re-encoding to FLAC. You do not need to change the command — the `-c:a flac` flag instructs FFmpeg to encode whatever audio stream it finds into FLAC, regardless of whether the source is AAC or MP3.
Technical Notes
3G2 (3GPP2) is a close relative of the MP4/MOV container family, sharing the ISO Base Media File Format lineage, which is why FFmpeg handles it reliably. The audio inside a 3G2 is almost always AAC at a low bitrate (often 64–128 kbps) optimized for CDMA network transmission, meaning the source material itself has already undergone lossy compression. When FFmpeg executes this conversion, it fully decodes the AAC stream to PCM and then encodes that PCM audio to FLAC — a process called transcoding (not remuxing). There is no way to 'copy' AAC directly into a FLAC file, since FLAC only supports its own lossless codec. The `-vn` flag is essential here to suppress video output; without it, FFmpeg would error because FLAC is a pure audio format with no video stream support. FLAC files produced by this conversion will support seeking and can carry Replay Gain metadata added in post-processing. One known limitation: 3G2 files do not support multiple audio tracks or subtitles, so there is no risk of losing secondary streams — the container is always single-track audio.