Convert RMI to AIFF — Free Online Converter
Convert RIFF MIDI (.rmi) to Audio Interchange File Format (.aiff) online for free. Fast, secure audio conversion with no watermarks or registration....
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How to Convert
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.
Click Convert and download your .aiff file when it's ready.
About RMI to AIFF Conversion
RMI (RIFF MIDI) is a Windows-native container that envelops Standard MIDI File data within the RIFF (Resource Interchange File Format) binary structure. Designed for the Windows Multimedia Extensions introduced in Windows 3.1, RMI leveraged the same RIFF infrastructure as WAV audio files, allowing Windows applications to manage MIDI content through unified RIFF parsing APIs. The format was processed by the mciSendCommand interface and later by DirectMusic for interactive game audio.
AIFF (Audio Interchange File Format) is Apple's uncompressed audio standard, storing raw PCM samples at full resolution. Converting RMI to AIFF extracts the MIDI data from its Windows RIFF container, renders it through a software synthesizer, and captures the complete audio output as uncompressed PCM in the AIFF container. This produces a master-quality audio file from Windows multimedia MIDI content.
Why Convert RMI to AIFF?
RMI is a dead-end format outside Windows — Apple systems have never recognized the RIFF MIDI container, and macOS audio APIs (Core Audio, AVFoundation) cannot parse it. Converting to AIFF creates an uncompressed audio rendering in Apple's native professional format, suitable for Logic Pro, GarageBand, and Final Cut Pro workflows.
For archival purposes, AIFF preserves the full fidelity of the MIDI synthesis without any lossy compression. If you are migrating a legacy Windows multimedia project to the Apple ecosystem — repurposing DirectMusic game audio for an iOS port, for instance — AIFF provides the lossless source file from which all other formats can be derived.
Common Use Cases
- Porting DirectMusic game soundtracks from Windows RMI to AIFF for iOS game development in Xcode
- Importing Windows multimedia training audio into Logic Pro for professional re-mixing and mastering
- Creating archival-quality uncompressed renders of legacy Windows kiosk background music
- Preparing Windows MCI audio content as AIFF stems for macOS video post-production
- Building sample libraries from Windows-era MIDI compositions rendered at full PCM resolution
How It Works
FFmpeg reads the RIFF container header, verifies the 'RMID' form type, and extracts the MIDI data chunk from the RIFF structure. The MIDI stream is parsed for SMF header information (format type, track count, timing resolution) and dispatched to a software synthesizer. The synthesizer maps MIDI program changes to SoundFont instrument patches, renders note events with velocity-sensitive amplitude and ADSR envelopes, and produces stereo PCM audio. This PCM stream — typically 16-bit or 24-bit at 44.1 kHz or 48 kHz — is written into an AIFF container using big-endian PCM format with FORM/COMM/SSND chunks.
Quality & Performance
AIFF stores uncompressed PCM, introducing zero quality loss in the encoding step. The entire quality equation depends on the SoundFont used for synthesis. RMI files created for Windows systems were typically heard through the Microsoft GS Wavetable Synth, which has a particular tonal character. Using a different SoundFont during conversion will produce different timbres. For the most authentic recreation, consider using a SoundFont that closely matches the Microsoft GS instrument set.
Device Compatibility
| Device | RMI | AIFF |
|---|---|---|
| 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
- 1Render at 48 kHz 24-bit if the AIFF will be used in further studio production on macOS — this preserves maximum headroom for processing
- 2Use a SoundFont that approximates the Microsoft GS Wavetable Synth if authentic Windows-era playback character is important
- 3Normalize the rendered AIFF output to -1 dBFS for consistent loudness when mixing with other audio sources
- 4Keep the original RMI file alongside the AIFF render — the MIDI data can be re-rendered with different SoundFonts later if needed
- 5Extract and document any RIFF INFO metadata (title, artist, copyright) before conversion, as this information does not transfer to AIFF automatically
RMI to AIFF extracts Windows MIDI content and renders it as uncompressed audio for the Apple professional ecosystem. This is the ideal pathway for lossless migration from Windows multimedia to macOS production workflows.