XMI vs MID: Miles Sound System Extended MIDI vs Standard MIDI
A technical comparison between Miles Sound System Extended MIDI (.xmi) game music files and Standard MIDI (.mid). Discover multi-track event streaming, delta intervals, and modern audio conversion.
Miles Sound System Extended MIDI (.xmi) is a specialized game audio sequence format created in 1991 by John Miles for MS-DOS PC gaming titles from Sierra, Origin, LucasArts, and BioWare. Standard MIDI Files (.mid) represent a hardware-agnostic digital music specification published by the MIDI Manufacturers Association to encode note numbers, velocity, and timing parameters across electronic synthesizers.
| FEATURE | XMI | MIDI |
|---|---|---|
| Original Creator | John Miles / Miles Design (1991) | Dave Smith & MIDI Consortium (1983) |
| File Container | IFF FORM XMID Chunk Hierarchy | Standard MThd / MTrk Chunk Hierarchy |
| Delta Timing Scheme | Cumulative sub-128 byte intervals | Variable-Length Quantity (VLQ) |
| Note Duration | Directly embedded in Note On events | Calculated via paired Note Off messages |
| Modern Browser Playback | Requires dedicated converter or emulator | Requires Web Audio SoundFont synthesizer |
- Optimized for low-latency interrupt playback in resource-constrained MS-DOS game engines
- Encapsulates timbre bank assignments (TIMB chunks) and sequence catalogs inside IFF containers
- Powers classic video game soundtracks from Wing Commander, Ultima, Theme Park, and Warcraft
- Preserves authentic 1990s PC gaming arrangements with dedicated channel velocity curves
- Universal playback support across all modern operating systems, web browsers, and media players
- Easily loaded into any Digital Audio Workstation (DAW) for remixing with modern virtual instruments
- Supports standard 16-channel MIDI orchestrations with standardized General MIDI sound banks
- Ubiquitous standard with decades of tool support and cross-platform software integration
Standard MIDI is universal, but XMI remains the quintessential soundtrack format of 1990s MS-DOS PC gaming. convrtr parses IFF XMID containers and synthesizes multi-harmonic voices into crisp 16-bit linear stereo WAV audio directly in your browser.
Converting files between XMI and MIDI frequently? The convrtr Chrome Extension lets you right-click any image on any webpage or open the Side Panel to convert assets instantly using local WebAssembly with zero server uploads.