Convert RMI to AMR — Free Online Converter
Convert RIFF MIDI (.rmi) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registration....
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Upload your .rmi file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
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About RMI to AMR Conversion
RMI (RIFF MIDI) is Microsoft's RIFF-containerized MIDI format, designed for the Windows Multimedia Extensions that shipped with Windows 3.1 and persisted through the DirectX era. The RIFF structure allows RMI files to carry metadata in standardized sub-chunks (INFO, DISP) and be managed by the same COM-based APIs that handle WAV and AVI files. RMI was the default format when Windows applications called midiStreamOut or used the MCI sequencer device.
AMR (Adaptive Multi-Rate) is a narrowband speech codec standardized by ETSI for GSM mobile telephony, operating at bitrates from 4.75 to 12.2 kbps. Converting RMI to AMR extracts MIDI from the Windows RIFF container, renders it via software synthesis, and compresses the audio using AMR's speech-optimized CELP coding. This produces ultra-small files for mobile telephony channels, though musical content suffers severely from AMR's 300-3400 Hz bandwidth limitation.
Why Convert RMI to AMR?
Specific mobile telephony infrastructure — MMS gateways, IVR systems, voicemail servers, and legacy feature phone platforms — accepts only AMR audio input. If Windows-authored RMI notification sounds or hold music must be deployed through these telecom channels, AMR conversion is the only viable path. No telecom system supports RIFF MIDI natively.
The conversion is driven by compatibility requirements, not quality goals. RMI files used as Windows system sounds, point-of-sale notification tones, or kiosk alert melodies can be converted to AMR for delivery through mobile voice networks where file size and codec compatibility outweigh audio fidelity.
Common Use Cases
- Converting Windows point-of-sale notification RMI sounds to AMR for mobile worker alert systems
- Preparing Windows telephony hold music from RMI to AMR for IVR system integration
- Creating mobile voicemail greetings from Windows-authored RMI melodies via AMR encoding
- Migrating Windows CE device alert tones to AMR for legacy feature phone distribution via MMS
- Producing ultra-small audio files from Windows kiosk RMI sounds for bandwidth-constrained mobile networks
How It Works
FFmpeg parses the RIFF container header, extracts the MIDI data chunk from the RMID form, and feeds the event stream to a software synthesizer with a General MIDI SoundFont. The synthesizer renders all MIDI channels to stereo PCM, which is then downsampled to 8 kHz mono — a requirement of AMR-NB. The mono signal is encoded using libopencore-amrnb with algebraic CELP (Code-Excited Linear Prediction) optimized for speech spectral characteristics. The output bandwidth is limited to 300-3400 Hz, discarding all content above 3.4 kHz.
Quality & Performance
AMR is fundamentally incompatible with musical content. The 300-3400 Hz bandwidth eliminates most harmonics, overtones, and transient detail that give instruments their character. Synthesized MIDI rendered through AMR sounds severely degraded — cymbals and high-frequency instruments disappear, sustained tones exhibit warbling CELP artifacts, and polyphonic passages become muddy. Simple monophonic melodies (single-line notification tones) survive more recognizably than complex arrangements. The SoundFont quality is largely irrelevant at these extreme compression levels.
Device Compatibility
| Device | RMI | 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
- 1Simplify the RMI's MIDI arrangement to a single melody line before conversion for the most recognizable AMR output
- 2Use AMR-WB at 23.85 kbps instead of AMR-NB when the target telephony system supports wideband — the wider bandwidth preserves substantially more musical detail
- 3Keep RMI notification sounds under 15 seconds for ringtone and alert use cases on feature phones
- 4Test the AMR output on the actual target handset or IVR system — playback quality varies significantly across telephony hardware
- 5Consider M4A or MP3 instead of AMR if the target mobile device supports modern audio formats — AMR should be a last resort for music
RMI to AMR is a niche conversion for mobile telephony compatibility. Use it only when telecom infrastructure requires AMR — for any other purpose, convert to AAC, MP3, or OGG instead.