Convert MIDI to AMR — Free Online Converter
Convert Standard MIDI File (.midi) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registrati...
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Upload your .midi 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 MIDI to AMR Conversion
MIDI (.midi) is a symbolic music format where each file encodes a complete musical performance as a sequence of machine-readable instructions. The format supports 16 independent channels (channel 10 reserved for percussion per the General MIDI specification), 128 melodic instrument programs, and a rich set of continuous controllers for expressive performance. The .midi extension is the unabbreviated Standard MIDI File designation, commonly encountered in Linux audio workflows and cross-platform music applications.
AMR (Adaptive Multi-Rate) is a speech codec developed by the European Telecommunications Standards Institute (ETSI) specifically for voice communication over GSM cellular networks. It operates at 8 kHz sampling with bitrates from 4.75 to 12.2 kbps. Converting MIDI to AMR is an extreme compression scenario — synthesizing a rich musical performance into a codec designed exclusively for human speech. The result is suitable only for telephony-specific use cases.
Why Convert MIDI to AMR?
IVR (Interactive Voice Response) systems in call centers and automated phone trees frequently require AMR-formatted audio for music-on-hold, menu navigation tones, and branding jingles. MIDI compositions of simple melodies can be rendered to AMR for deployment across telephony infrastructure where no other audio format is supported.
Embedded telephony devices — automotive hands-free systems, elevator intercoms, security intercom panels — often support only AMR decoding hardware. When these systems need melodic alerts or branded audio notifications based on MIDI compositions, AMR is the only viable delivery format despite its severe musical limitations.
Common Use Cases
- Creating music-on-hold audio from MIDI melodies for IVR telephony systems
- Rendering MIDI jingles as AMR for automated phone tree branding in call centers
- Converting simple MIDI notification tones for embedded automotive hands-free units
- Preparing MIDI-based alert melodies as AMR for building security intercom systems
- Generating AMR audio from MIDI for deployment on GSM-era telecom infrastructure
How It Works
FFmpeg decodes the .midi file and synthesizes audio through a SoundFont engine, producing a stereo PCM waveform. This waveform is then drastically processed for AMR compatibility: downmixed from stereo to mono, resampled from the synthesis rate (typically 44.1/48 kHz) to 8 kHz, and low-pass filtered to remove all content above 3.4 kHz. The AMR-NB encoder (libopencore-amrnb) then applies algebraic CELP (Code-Excited Linear Prediction) analysis — a model designed to represent the human vocal tract, not musical instruments — at the selected bitrate. The output is a .amr file with a six-byte AMR header followed by encoded frames.
Quality & Performance
AMR-NB encoding devastates musical content. The 8 kHz sample rate (3.4 kHz Nyquist limit) eliminates all frequencies above 3400 Hz — meaning cymbals, flutes, violins' upper harmonics, and most of what makes music sound like music is simply gone. The CELP model further distorts the signal because it models excitation patterns optimized for speech formants, not sustained musical tones. Only the simplest monophonic melodies — single-note ringtone-style sequences — produce recognizable musical results. Polyphonic content becomes unintelligible noise.
Device Compatibility
| Device | MIDI | 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
- 1Reduce the MIDI to a single monophonic melody line for the most intelligible AMR output possible
- 2Always encode at the maximum 12.2 kbps AMR-NB bitrate to preserve as much musical content as the codec allows
- 3Remove all percussion (MIDI channel 10) before conversion — drums produce the worst AMR artifacts
- 4Use AMR-WB at 23.85 kbps when the telephony system supports wideband — the improvement for music is substantial
- 5Test the AMR output through the actual telephone handset or speakerphone that end users will hear — headphone testing gives a misleadingly optimistic impression
MIDI to AMR serves telephony-only deployments where AMR is the sole supported codec. Limit MIDI content to simple monophonic melodies for any chance of recognizable output.