Convert 3G2 to M4A — Free Online Tool
Convert 3G2 mobile video files to M4A audio by stripping the video stream and extracting the AAC audio track into an iTunes-compatible MPEG-4 audio container. Ideal for salvaging audio from old CDMA-era phone recordings without any re-encoding quality loss when the source already uses AAC.
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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
3G2 is a multimedia container developed for CDMA mobile networks (used by carriers like Verizon and Sprint) that typically bundles H.264 video with AAC audio. M4A is an MPEG-4 container that holds only audio — it is essentially the same container format as MP4 but without a video track. During this conversion, the video stream is completely discarded using the -vn flag, and the AAC audio stream from the 3G2 file is passed directly into the M4A container. Because both 3G2 and M4A natively support AAC, the audio does not need to be re-encoded — it is extracted and remuxed as-is, meaning there is zero additional quality loss beyond what was already present in the original lossy recording. The result is a clean, iTunes and Apple Music compatible M4A file containing only the audio.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that handles reading the 3G2 container, demuxing its streams, and writing the M4A output. This same binary runs under the hood in your browser via WebAssembly. |
-i input.3g2
|
Specifies the input file — a 3G2 container from a CDMA-era mobile device, which typically contains an H.264 video stream and an AAC audio stream bundled together for mobile network transmission. |
-c:a aac
|
Sets the audio codec for the output to AAC (Advanced Audio Coding). Since 3G2 files already use AAC audio and M4A is the standard iTunes AAC container, this ensures the output is encoded in the correct format — and in practice FFmpeg will often pass the AAC stream through directly without re-encoding. |
-b:a 128k
|
Sets the target audio bitrate to 128 kilobits per second, a standard quality level for AAC that balances file size and fidelity. For voice recordings from 3G2 mobile files, this is typically equal to or higher than the original bitrate, so no quality is lost. |
-vn
|
Stands for 'video none' — explicitly tells FFmpeg to discard all video streams from the 3G2 input and write no video data to the output. This is required because M4A is a strictly audio-only container and cannot hold a video track. |
output.m4a
|
The output filename with the .m4a extension, which signals FFmpeg to write an MPEG-4 audio container. The M4A format is natively recognized by iTunes, Apple Music, iOS, and most modern media players as a standard AAC audio file. |
Common Use Cases
- Extracting voice memos or audio recordings made on older CDMA smartphones (Verizon, Sprint) and importing them into iTunes or Apple Music for archiving
- Recovering spoken audio from 3G2 home videos shot on early-2000s flip phones to create audio keepsakes without the degraded video
- Converting 3G2 podcast or radio segments downloaded from mobile platforms into M4A for playback in Apple Podcasts or other AAC-compatible players
- Stripping video from 3G2 lecture or meeting recordings to produce lightweight audio-only files that are easier to share and store
- Preparing audio from 3G2 ringtone or music clip files for use in iOS apps or media libraries that require the M4A format
- Archiving audio from a collection of legacy 3G2 mobile files into a more universally supported long-term format before the original files become unplayable
Frequently Asked Questions
In most cases, no — there is no additional quality loss. Because 3G2 files almost always use AAC audio and M4A also stores AAC, the audio stream is remuxed (copied directly) rather than re-encoded. The command uses -c:a aac with -b:a 128k as a fallback encoder setting, but if your 3G2 file's audio is already AAC-encoded, FFmpeg will pass it through without decoding and re-encoding. The audio quality is exactly what was captured on your mobile device originally.
The video is discarded during the conversion process by the -vn flag, which tells FFmpeg to exclude all video streams from the output. The original 3G2 file on your device is not modified, so the video remains accessible there. If you need both audio and video preserved, you should instead convert to a format like MP4 rather than M4A, which is strictly an audio-only container.
3G2 was designed specifically for the CDMA mobile network ecosystem and has very limited software support today — many modern media players, DAWs, and streaming platforms either refuse to play it or handle it poorly. M4A is a widely adopted standard supported natively by Apple devices, iTunes, VLC, and most audio editing software. It also supports iTunes metadata fields like track title, artist, album art, and chapter markers, which 3G2 does not.
Replace the value after -b:a in the command. For example, change -b:a 128k to -b:a 192k for higher quality or -b:a 96k for a smaller file size. For 3G2 files recorded on mobile phones, the original audio was often encoded at 64k or 96k, so setting a higher output bitrate will not recover detail that was never there — matching or slightly exceeding the original bitrate is usually the best choice. The M4A format supports bitrates up to 320k.
Yes. On Linux or macOS, you can use a shell loop: for f in *.3g2; do ffmpeg -i "$f" -c:a aac -b:a 128k -vn "${f%.3g2}.m4a"; done. On Windows Command Prompt, use: for %f in (*.3g2) do ffmpeg -i "%f" -c:a aac -b:a 128k -vn "%~nf.m4a". This processes every 3G2 file in the current directory and outputs a corresponding M4A file with the same base filename.
Basic metadata tags embedded in the 3G2 container are typically carried over by FFmpeg during remuxing, but 3G2 files from mobile phones rarely contain rich metadata beyond a creation timestamp. The M4A format supports a much richer set of iTunes-style metadata tags (artist, album, track number, artwork, chapters), but those fields will simply be empty unless you populate them manually after conversion using a tag editor like MusicBrainz Picard or iTunes.
Technical Notes
3G2 uses the same ISO Base Media File Format (ISOBMFF) foundation as MP4 and M4A, which is why remuxing the audio stream is straightforward and lossless at the container level. The -vn flag is essential here because M4A explicitly excludes video tracks — attempting to copy a video stream into an M4A container would cause an error or produce an unplayable file. The AAC audio codec used in 3G2 files is typically AAC-LC (Low Complexity), which is the same profile used in M4A files for iTunes and Apple Music, ensuring full compatibility. One limitation to be aware of: if your 3G2 file used AMR-NB or EVRC audio (uncommon but possible on older CDMA feature phones), the audio will be re-encoded to AAC during conversion, which involves a lossy transcode. The M4A output will support gapless playback and iTunes chapter markers for podcasts, though no chapter data will be present unless added separately. File sizes will be smaller than the original 3G2 because the video stream, which accounts for most of the data, is removed entirely.