Convert 3GPP2 Multimedia (.3g2) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure video conversion with no watermarks or registration.
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AMR (Adaptive Multi-Rate) is the native audio codec used inside most 3G2 files, designed specifically for efficient speech encoding over cellular networks. Converting 3G2 to standalone AMR extracts this audio track and saves it as an independent .amr file, stripping away the video component entirely. This is essentially a demux operation that isolates the audio bitstream from the 3GPP2 container.
The AMR codec was ubiquitous in the feature phone era and remains supported by many embedded systems, VoIP platforms, and telecommunications tools. Standalone .amr files are compact — a minute of speech uses only about 90 KB at the standard 12.2 kbps rate — making them practical for storage-constrained applications and low-bandwidth transmission.
The main reason to extract AMR from 3G2 is to isolate the audio for use in systems that expect standalone AMR input — telephony platforms, IVR systems, SMS/MMS gateways, and embedded devices. Many telecom-grade tools process .amr files directly but cannot parse the 3G2 container. Extracting the audio eliminates the video overhead and produces the smallest possible audio file.
AMR extraction is also useful for forensic and archival purposes. When you need the raw audio bitstream exactly as it was encoded by the phone's hardware — without any transcoding — demuxing to standalone AMR preserves the original encoding bit-for-bit, including any artifacts that might be relevant for analysis or authentication.
When the 3G2 file contains AMR audio (which most do), FFmpeg performs a pure demux — copying the AMR bitstream out of the 3GPP2 container into a standalone .amr file without any re-encoding. This uses -acodec copy and -vn flags. The .amr file header is a simple '#!AMR\n' magic byte sequence followed by the raw AMR frames. AMR-NB operates at 8 kHz with bitrates from 4.75 to 12.2 kbps; AMR-WB operates at 16 kHz with bitrates from 6.6 to 23.85 kbps.
When the source 3G2 already contains AMR audio (the common case), the extraction is bitstream-identical — zero quality change occurs. If the 3G2 contains AAC audio instead, FFmpeg must transcode to AMR, which will reduce quality since AMR is a narrowband speech codec. In either case, the audio fidelity is limited to what AMR can represent: telephone-quality speech at 8 kHz or wideband speech at 16 kHz.
| Device | 3G2 | AMR |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| 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
Converting 3G2 to AMR is a targeted extraction for telecom, forensic, and embedded use cases. When the source contains AMR audio natively, the operation is a lossless demux that produces the smallest possible audio output.
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Mọi trình duyệt, mọi thiết bị
| Tính năng | 3G2 | AMR |
|---|---|---|
| Tên đầy đủ | 3GPP2 Multimedia | Adaptive Multi-Rate Audio |
| Phần mở rộng | .3g2 | .amr |
| Phù hợp nhất cho | Mobile optimized | Speech optimized |