What You Can Configure
MultiMon has no settings window — what is actually configurable, the environment-variable escape hatches, and how device-removed recovery behaves.
MultiMon has no settings window. There is no menu bar and no preferences dialog. What you can change lives in the single main window, plus a handful of environment variables covered at the end of this page.
Mode
The mode dropdown chooses how your outputs are driven, and has four entries:
- Span — one source across every display MultiMon detects. There is no monitor selection, and each screen takes an equal share per screen rather than per pixel.
- Individual — one source per monitor, free-running unless you tick Sync.
- Hap — one HAP clip per monitor, always on the one shared clock.
- Split — one source cut into a grid.
See Video wall setup.
Grid rows and columns
In Split mode the main window shows an Auto (by screens) tickbox with rows and columns fields, defaulting to a 2×2 grid. With Auto ticked, MultiMon derives a near-square grid from the number of screens it detects — four give 2×2, six give 2×3, nine give 3×3 — and the rows and columns fields are read-only. Untick it to set them yourself.
Each monitor slot takes a row,col mapping saying which cell it shows. A monitor with no cell stays
black.
Sync
In Individual mode there is a checkbox labelled Sync (frame-lock same-length clips), which runs every source off the shared master clock. Frame-lock holds only for clips of equal duration. Span, Split and Hap are inherently on the shared clock and have no checkbox. See Video synchronisation.
Audio device
One AUDIO DEVICE dropdown sits beside the mode dropdown and applies to the whole show: every track is sent to that device. There is no per-track output device.
The audio mixer
The inline mixer has a MASTER fader and Mute, an Add audio… button for standalone stems
(mp3, wav, flac, aac, m4a, and the audio of an mp4 or mov), and per track volume, pan,
mute, solo and remove. See Audio mixer.
Current limitation: per-link mixer overrides set within a perform session are not saved into the project file.
Projects
New, Open project and Save project manage a .mmproj file — JSON, schema version 2. Version
1 project files are migrated automatically when you open them.
Only open .mmproj files you created: the media paths inside a project file, including UNC paths, are
used as written.
FFmpeg discovery
Convert to HAP runs FFmpeg, resolved from your PATH. There is no field in which to set a path
to FFmpeg — if the conversion cannot find it, install FFmpeg (from a source you trust) and make sure it
is on your PATH. No other feature requires it.
Keys
| Key | What it does |
|---|---|
F11 | Toggle perform mode |
Space | Pause / resume while performing |
Esc | Exit perform mode |
The PERFORM and Stop buttons in the transport row do the same job. There is no key remapping.
Environment variables
MultiMon reads a few environment variables as escape hatches and cross-GPU testing hooks. None of them has a setting in the interface:
| Variable | Effect |
|---|---|
MULTIMON_FORCE_SW_DECODE | Media Foundation skips the hardware bind and decodes H.264 and HEVC in software |
MULTIMON_DISABLE_HAP | Turns the HAP decode path off; HAP clips are handed to Media Foundation instead |
MULTIMON_FEATURE_LEVEL | Pins the Direct3D feature level to 11_1 or 11_0 |
MultiMon also carries a named list of GPUs whose hardware video decode is known to be unreliable and switches those to software decode on its own, with no variable needed. See Standard playback.
Device-removed recovery
If the graphics device is lost — a GPU reset, a driver restart, a display pulled — MultiMon detects it, rebuilds the device and its resources, and resumes playback from the master clock. There is nothing to configure and nothing to press: recovery is automatic, and the show carries on from where the clock says it should be.
Audio recovery is bounded rather than indefinite. If the audio device is removed, MultiMon rebuilds the WASAPI endpoint and retries three times; if that fails, that output stops for the rest of the show while the application and the video carry on.
Identify screens
Identify screens puts a numbered overlay on every display so you can confirm which physical screen is which. The overlays hide themselves when you enter perform mode.