What is the IDF file format?
.idf is a plain-text file that stores MIDI instrument definition settings. .idf configuration files are used by MIDI sequencers and audio-production software to describe instruments assigned to each playback channel.
Each channel can represent a music instrument or a different audio device - for example, a car horn or the sound of a laser. .idf files define such devices, recording the device name, MIDI channel assignments, key maps, bank and patch names, and controller mappings. Each .idf file is associated with a specific instrument definition, and any changes made to it may affect other applications that use .MIDI playback.
Because .idf is a plain-text format with no fixed binary signature, it can be opened and edited in any text editor such as Notepad or Notepad++. Note that the closely related instrument definition format used by Cakewalk and SONAR adopts the .ins extension rather than .idf.
Security & safety
RISK: LOWA MIDI instrument definition is a small plain-text file with no executable content, so it is low risk. The only caution is identity confusion: an .idf you downloaded might actually be an EnergyPlus simulation input (also text) or something else entirely - open it in a text editor first to confirm what it is before feeding it to audio software. Avoid sketchy "IDF viewer" download sites that bundle adware; a plain text editor is all you need.
Format details
in a nutshell- EnergyPlus Input Data File (.idf) - A plain-text building-energy simulation input describing the building and HVAC system; the most widely documented .idf type, edited with EnergyPlus IDF Editor or a text editor.
- InspireData / Inspiration data file - The original db_name; an education data-visualization document - but InspireData/Inspiration files typically use .idi/.isf, so this label appears to be a mistaken association.
- Image Description File / generic instrument data - Several niche tools (imaging, instrumentation) emit unrelated .idf data files.
Programs that open IDF files
Windows3 apps
The MIDI sequencer that uses it
Free Import/place the instrument definition in your sequencer so patch and bank names appear correctly (note many sequencers expect .ins). 
macOS1 app
Text editor (TextEdit / BBEdit)
Freemium Open the .idf as plain text (TextEdit: Format > Make Plain Text) to read/edit. 
Linux1 app
Any text editor (gedit, nano, VS Code)
Open-source Open the plain-text .idf to inspect or edit the definition.
Docpose online IDF viewer
Free Upload to view the MIDI instrument definition in the browser (do not upload sensitive files to third-party sites). Technical details
deep spec| File type | Plain-text instrument definition and settings file |
| Text encoding | ASCII or UTF-8 |
| Internal structure | Human-readable sections with key/value pairs covering instrument ID, MIDI channel assignments, key maps, bank and patch names, voice names, and controller data |
| File signature (magic bytes) | None - no fixed binary header; identified by its readable MIDI-definition text content |
| MIME type | text/plain |
| Typical file size | A few KB to tens of KB |
| Platform support | Windows, macOS, Linux |
| Consumed by | MIDI sequencers and audio-production applications; not a directly playable media file |
| Editable with | Any plain-text editor (Notepad, Notepad++, TextEdit, VS Code, nano) |
| Related extensions | .ins (similar instrument-definition role), .mid and .midi (MIDI sequence files that reference instrument definitions) |
| Instrument-definition note | Cakewalk and SONAR use the .ins extension for their instrument definitions, not .idf; the two formats serve the same purpose but are not interchangeable |
| Era of adoption | 1990s, coinciding with the rise of desktop MIDI sequencing software |
| Released | 1990s, alongside desktop MIDI sequencers |
IDF conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about IDF files.
