Convert M4P to AMR — Free Online Converter
Convert iTunes Protected AAC (.m4p) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registrat...
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How to Convert
Upload your .m4p 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 M4P to AMR Conversion
M4P is Apple's protected iTunes audio format containing AAC-encoded music at 128-256 kbps. AMR (Adaptive Multi-Rate) is a narrowband speech codec standardized by 3GPP, operating at bitrates from 4.75 to 12.2 kbps with an 8 kHz sample rate. Converting M4P to AMR is an extreme downgrade in audio quality, designed for telephony and voice messaging applications where file size and voice clarity trump musical fidelity.
This conversion only works on unprotected M4P files where FairPlay DRM has been removed. Once DRM-free, FFmpeg decodes the AAC stream and re-encodes it through the AMR-NB codec (libopencore_amrnb), producing tiny files suitable for voicemail systems, IVR platforms, and legacy mobile messaging.
Why Convert M4P to AMR?
AMR is the standard codec for GSM voice recordings and voicemail systems worldwide. If you need to extract spoken-word content from old iTunes audiobook or podcast purchases and deliver it through a telephony platform, AMR is the required format. IVR (Interactive Voice Response) systems, voicemail servers, and some call center platforms accept only AMR or PCM input.
The extreme compression ratio also makes AMR useful for bandwidth-constrained scenarios. A full hour of speech in AMR at 12.2 kbps is only about 5.4 MB — over 40x smaller than the same content in a 256 kbps M4P file. This matters for bulk distribution of audio content to markets with limited bandwidth.
Common Use Cases
- Convert iTunes spoken-word purchases to AMR for voicemail or IVR system integration
- Create ultra-compact audio files from M4P for bandwidth-limited distribution channels
- Prepare old iTunes audiobook content for telephony-based education platforms
- Extract voice recordings from M4P for use in GSM-based messaging systems
- Generate minimal-size audio clips from iTunes purchases for embedded device playback
How It Works
FFmpeg decodes the AAC audio from the unprotected M4P file and re-encodes it using libopencore_amrnb at 8 kHz sample rate, mono channel, with selectable bitrate modes from 4.75 to 12.2 kbps. The AMR codec uses ACELP (Algebraic Code-Excited Linear Prediction) optimized for human speech frequencies (300-3400 Hz). The output .amr file has a 6-byte magic header (#!AMR\n) followed by packed codec frames. All stereo information from the source is downmixed to mono.
Quality & Performance
Quality loss is severe for music. M4P at 128-256 kbps captures full 20 kHz frequency range; AMR-NB at 12.2 kbps captures only 300-3400 Hz. Musical instruments, bass lines, and high-frequency details are completely eliminated. Spoken-word content (podcasts, audiobooks) remains clearly intelligible — AMR was designed for speech, and it handles voice well within its frequency range. Expect telephone-call quality at best.
Device Compatibility
| Device | M4P | AMR |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No | No |
Recommended Settings by Platform
Spotify
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Apple Music
Resolution: N/A
Bitrate: 256 kbps
AAC format required
SoundCloud
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Podcast
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
Tips for Best Results
- 1Only convert spoken-word M4P content to AMR — music will be unrecognizable
- 2Use 12.2 kbps mode for the best speech clarity AMR-NB can deliver
- 3Verify DRM is removed first; use iTunes Match for legal DRM-free upgrades
- 4Test the output on your target telephony system before batch converting
- 5Consider WAV or MP3 as intermediate formats if your pipeline needs preprocessing before AMR
M4P to AMR is strictly for speech and telephony applications where file size matters more than musical fidelity. Remove DRM first, then convert spoken-word content for best results.