Convert MPEG Audio Layer 1 (.mp1) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registration.
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Converting MP1 to AMR re-encodes audio from the first MPEG audio standard into the Adaptive Multi-Rate speech codec used in GSM telephony. Both are legacy formats from different eras and domains — MP1 from early 1990s multimedia, AMR from late 1990s mobile telecommunications.
This conversion takes MP1 audio (typically 384 kbps stereo) and dramatically compresses it to AMR-NB (8 kHz mono, 4.75-12.2 kbps). The quality degradation is extreme, making this conversion only appropriate for speech content destined for telephony systems.
If you have speech recordings stored as MP1 (from VCD or early digital systems) that need to be deployed on telephony platforms — IVR systems, voicemail, or MMS distribution — AMR is the required codec. This is a niche conversion bridging two legacy ecosystems.
AMR is still the default voice recording format on many feature phones and some Android devices. Converting MP1 speech content to AMR ensures compatibility with these mobile recording and playback systems.
FFmpeg decodes the MP1 subband audio to PCM, then resamples to 8 kHz mono and encodes using libopencore_amrnb. The AMR-NB codec uses ACELP (algebraic code-excited linear prediction) optimized for speech signals. The encoding chain: MP1 decode → PCM → resample 8 kHz → mono downmix → AMR-NB encode. The bitrate drops from typically 384 kbps (MP1 stereo) to 12.2 kbps (AMR-NB), a 30x reduction.
Quality loss is severe. MP1 at 384 kbps provides near-CD audio quality; AMR-NB at 12.2 kbps provides telephone-quality speech only. Music is essentially destroyed. Even speech shows noticeable compression — the 8 kHz bandwidth (4 kHz frequency range) discards all content above telephone band. Only convert speech content to AMR.
| Device | MP1 | AMR |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
MP1 to AMR bridges 1990s multimedia audio to mobile telephony. The extreme quality loss limits this conversion to speech-only content for telephony systems.
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| No |
| الميزة | MP1 | AMR |
|---|---|---|
| الاسم الكامل | MPEG Audio Layer 1 | Adaptive Multi-Rate Audio |
| الامتداد | .mp1 | .amr |
| الأفضل لـ | Early MPEG standard | Speech optimized |