Convert RMI to AAC — Free Online Converter

RMI (RIFF MIDI) encapsulates Standard MIDI File data within a RIFF container, the foundational binary structure Microsoft developed for Windows multimedia. The RIFF wrapper provides structured metadata storage through INFO sub-chunks — INAM (title), IART (artist), ICOP (copyright), ICMT (comments) — capabilities that raw .mid files lack entirely. RMI was the default MIDI format for Windows applications using the Multimedia Control Interface (MCI) and remained prevalent through the Windows XP era.

AAC (Advanced Audio Coding) is the dominant lossy audio codec powering Apple Music, YouTube, and virtually every modern streaming platform. Converting RMI to AAC strips the RIFF envelope, synthesizes the enclosed MIDI data through a software synthesizer, and encodes the rendered waveform as AAC. The result is a universally playable audio file derived from Windows-native MIDI content.

RMI files exist almost exclusively within Windows multimedia archives — corporate training modules built with Windows MCI, DirectX-era game assets, and educational software from the late 1990s. These files cannot be played on macOS, Linux, iOS, or Android without first extracting the MIDI data from the RIFF container. AAC conversion creates a universally compatible audio rendering.

AAC offers superior compression efficiency compared to MP3, making it the optimal lossy format for distributing rendered MIDI content. At 128 kbps, AAC delivers quality that rivals MP3 at 192 kbps. For organizations digitizing legacy Windows multimedia libraries, AAC provides the best balance of file size, audio quality, and universal device support.