Convert MP4 to AMR — Free Online Converter
Convert MPEG-4 Part 14 (.mp4) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure video conversion with no watermarks or registration....
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Upload your .mp4 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 .amr file when it's ready.
About MP4 to AMR Conversion
MP4 to AMR conversion extracts the audio track from an MPEG-4 video and encodes it in Adaptive Multi-Rate format. AMR was developed by the European Telecommunications Standards Institute (ETSI) specifically for cellular voice calls over GSM and 3G networks. It operates at extremely low bitrates (4.75 to 12.2 kbps) and is optimized for human speech rather than music or general audio.
Our converter decodes the MP4 audio and re-encodes it using the AMR-NB (Narrowband) codec at 8 kHz mono. The resulting file is tiny — a 10-minute recording produces an AMR file under 1 MB.
Why Convert MP4 to AMR?
AMR conversion makes sense when you need to extract voice content from video for telephony applications, voice messaging systems, or legacy mobile platforms. Many older VoIP systems, IVR (Interactive Voice Response) systems, and cellular voicemail platforms use AMR as their native format. If you are building content for distribution on 2G/3G networks where bandwidth is precious, AMR's extreme compression is unmatched. The format excels at speech intelligibility even at its lowest 4.75 kbps rate.
Common Use Cases
- Extract voiceover from training videos for use in IVR phone systems
- Create voice message files compatible with legacy cellular voicemail
- Prepare speech content for distribution over low-bandwidth 2G networks
- Reduce voice recording size for archival in telephony databases
- Generate audio clips for embedded devices with AMR-only decoders
How It Works
FFmpeg decodes the MP4 audio stream and re-encodes using the libopencore-amrnb encoder. The output is 8 kHz mono (narrowband), which is the AMR-NB standard. Bitrate options range from 4.75 to 12.2 kbps, with 12.2 kbps (Mode 7) providing the best speech quality. The AMR container stores frames of 20 ms each. For wideband speech, AMR-WB (16 kHz, up to 23.85 kbps) can be selected using the libopencore-amrwb encoder.
Quality & Performance
AMR is strictly a speech codec — music, environmental sounds, and complex audio will sound distorted and metallic. At 12.2 kbps, speech is clear and intelligible but noticeably compressed. At 4.75 kbps, speech remains understandable but sounds robotic. The 8 kHz sample rate means all frequencies above 4 kHz are discarded, eliminating most of what gives audio its richness. This is functional audio, not high-fidelity audio.
Device Compatibility
| Device | MP4 | AMR |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Native | Partial |
| Linux | Partial | Partial |
| Web Browser | Native | No |
Recommended Settings by Platform
YouTube
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
TikTok
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Twitter/X
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Discord
Resolution: 1280x720
Bitrate: 4 Mbps
8MB free, 50MB Nitro
Tips for Best Results
- 1Use 12.2 kbps (Mode 7) for the best speech clarity AMR can deliver
- 2Choose AMR-WB over AMR-NB if the target system supports it — the quality difference is significant
- 3AMR is mono only — stereo source audio will be downmixed automatically
- 4Test voice intelligibility at your chosen bitrate before committing to a batch conversion
- 5For music extraction, use AAC or MP3 instead — AMR is unsuitable for non-speech content
Related Conversions
MP4 to AMR is a specialized conversion for telephony, voice messaging, and ultra-low-bandwidth scenarios. The resulting files are remarkably small and perfectly suited for voice content delivery on constrained networks and legacy systems.