Convert RMI to ALAC — Free Online Converter
Convert RIFF MIDI (.rmi) to Apple Lossless Audio Codec (.alac) 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.
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About RMI to ALAC Conversion
RMI (RIFF MIDI) packages Standard MIDI File data inside Microsoft's RIFF binary container, the same foundational structure used by WAV and AVI. The format was integral to Windows multimedia programming — applications using the MCI (Media Control Interface) string commands like 'play sequencer' operated on RMI files through the system's MIDI mapper. The RIFF wrapper provides DISP (display) and INFO sub-chunks for metadata that standard MIDI headers cannot accommodate.
ALAC (Apple Lossless Audio Codec) compresses audio with zero data loss — every PCM sample is perfectly preserved after decompression. Converting RMI to ALAC strips the Windows RIFF envelope, synthesizes the MIDI data, and encodes the result as losslessly compressed audio in Apple's native format. This produces a space-efficient, bit-perfect audio file optimized for iTunes, iPhone, and Apple Music.
Why Convert RMI to ALAC?
RMI files are trapped inside the Windows multimedia ecosystem — the RIFF MIDI container is not recognized by Apple's Core Audio framework, Android's MediaPlayer, or any Linux audio subsystem. Converting to ALAC liberates the musical content into a lossless format that integrates seamlessly with Apple's entire device ecosystem while preserving full synthesis fidelity.
ALAC occupies roughly 50-60% of the space that uncompressed AIFF would require, with zero quality penalty. For archiving large collections of legacy Windows RMI content on Apple devices — preserving corporate training music, educational software soundtracks, or DirectMusic game compositions — ALAC provides the optimal balance of lossless quality and storage efficiency.
Common Use Cases
- Archiving corporate Windows multimedia RMI collections in Apple's lossless format for iTunes library management
- Migrating Windows CE device startup and notification RMI sounds to iPhone-native ALAC format
- Preserving DirectMusic game audio from Windows platforms as lossless ALAC for retro game music archives
- Converting Windows-era educational software RMI soundtracks for Apple Classroom distribution
- Building an Apple Music-compatible library from legacy Windows MIDI compositions stored as RMI
How It Works
FFmpeg detects the RIFF container by parsing the initial 12-byte header (RIFF size RMID) and locates the 'data' chunk containing the Standard MIDI File. The MIDI event stream is routed to a software synthesizer that maps General MIDI program numbers (0-127 melodic, channel 10 percussion) to SoundFont patches. Note events trigger sample-based oscillators with velocity-sensitive amplitude and ADSR envelope shaping. The mixed stereo PCM output is encoded using the ALAC codec — a lossless compression algorithm using adaptive linear prediction and Rice entropy coding — and packaged in an M4A (MPEG-4 Audio) container.
Quality & Performance
ALAC encoding is mathematically lossless — decoded output is bit-identical to the encoder input. The quality variable is solely the SoundFont used for synthesis. RMI files authored for Windows systems were designed to sound correct through the Microsoft GS Wavetable Synth (Roland Sound Canvas derivative). A different SoundFont will produce different instrument voicings, reverb character, and dynamic response. ALAC faithfully preserves whatever the synthesizer produces, including both strengths and synthesis artifacts.
Device Compatibility
| Device | RMI | ALAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Native |
| iPhone/iPad | Partial | Native |
| 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
- 1Keep the original RMI file archived alongside the ALAC render — MIDI data can be re-rendered with improved SoundFonts in the future
- 2Tag the ALAC output with metadata extracted from the RMI's RIFF INFO chunks to preserve attribution and copyright information
- 3Render at 44.1 kHz for music consumption or 48 kHz if the ALAC will be used in video production workflows
- 4Compare the ALAC render against Windows Media Player's RMI playback to assess SoundFont fidelity before batch converting
- 5Use a SoundFont with at least 200 MB of samples for noticeably better instrument realism over the default General MIDI bank
RMI to ALAC converts Windows RIFF MIDI content into losslessly compressed audio for Apple's ecosystem. The SoundFont determines musical quality; ALAC preserves it with bit-perfect fidelity.