Convert 3GPP2 Multimedia (.3g2) to MPEG-4 Audio (.m4a) online for free. Fast, secure video conversion with no watermarks or registration.
Upload your .3g2 file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .m4a file when it's ready.
M4A is the standard file extension for MPEG-4 Audio — essentially an MP4 container holding only an audio stream, typically AAC. Converting 3G2 to M4A extracts the audio from old CDMA phone recordings and packages it in the format used by iTunes, Apple Music, and the entire Apple audio ecosystem. M4A supports rich metadata including chapters, album art, lyrics, and podcast markers, making it the most feature-complete container for AAC audio.
Unlike raw .aac files, M4A wraps the audio in a proper MPEG-4 container with metadata atoms. This means you can add titles, dates, descriptions, and even album artwork to your extracted phone recordings — turning anonymous audio clips into properly cataloged, searchable files in your music library.
M4A is the format Apple uses for everything from iTunes Store purchases to Voice Memos recordings. If you want extracted phone audio to integrate seamlessly with Apple Music, iTunes, GarageBand, Logic Pro, or any Apple audio workflow, M4A is the native choice. The format appears in Finder with proper artwork thumbnails, plays in all Apple apps without codec installation, and syncs via iCloud.
Compared to raw .aac files, M4A provides a structured container with proper duration reporting, gapless playback support, and metadata tagging. Many media players and library managers (iTunes, Plex, Jellyfin) handle M4A more reliably than raw AAC streams, making it the preferred format for organized audio libraries.
FFmpeg decodes the AMR audio from the 3G2 container and re-encodes to AAC-LC at 128 kbps in an M4A container (MPEG-4 with audio-only muxing). If the 3G2 already contains AAC audio, FFmpeg can stream-copy the audio bitstream directly into M4A without re-encoding using '-acodec copy'. The M4A container's moov atom stores duration, sample rate, and metadata atoms for iTunes-compatible tagging. The -vn flag strips the video track.
When the 3G2 contains AAC audio and stream copy is used, the extraction is lossless — bit-identical audio in a new container. When transcoding from AMR to AAC, the conversion preserves the full fidelity of the source but cannot improve upon the original phone recording quality. At 128 kbps AAC, the output is transparent for telephone-grade source material.
| Device | 3G2 | M4A |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Native |
| iPhone/iPad | Partial | Native |
| Android | Native | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Resolution: 1280x720
Bitrate: 4 Mbps
8MB free, 50MB Nitro
Converting 3G2 to M4A is ideal for Apple ecosystem users who want properly tagged, library-integrated audio from old phone recordings. The M4A container provides the metadata and compatibility features that make raw AAC files impractical for organized collections.
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| No |
| 기능 | 3G2 | M4A |
|---|---|---|
| 전체 이름 | 3GPP2 Multimedia | MPEG-4 Audio |
| 확장자 | .3g2 | .m4a |
| 최적 용도 | Mobile optimized | Better than MP3 |