Settings & Configuration

Accessing Settings

Open the Settings dialog from the main menu or use the keyboard shortcut. Settings are organized into categories for easy navigation.

Hardware Acceleration

MultiMon offers multiple hardware acceleration modes to optimize video playback performance based on your system configuration.

Acceleration Modes

Mode	Description	Best For
Auto	Automatically selects the best available method	Most users (recommended)
D3D11VA	Direct3D 11 Video Acceleration	Modern NVIDIA/AMD/Intel GPUs
DXVA2	DirectX Video Acceleration 2	Older systems, broad compatibility
None	Software decoding only	Troubleshooting, compatibility issues

How Hardware Acceleration Works

Hardware acceleration offloads video decoding from your CPU to your GPU:

1. Compressed video data is read from disk
2. GPU video decoder decompresses frames directly
3. Decoded frames stay in GPU memory
4. Display happens without CPU involvement

This reduces CPU usage significantly, especially for high-resolution content.

Auto Mode (Recommended)

Auto mode intelligently selects the best acceleration method:

1. Checks if D3D11VA is available and functional
2. Falls back to DXVA2 if D3D11VA fails
3. Uses software decoding as final fallback
4. Logs the selected method for troubleshooting

Use Auto mode unless you have specific compatibility issues.

D3D11VA (Direct3D 11 Video Acceleration)

D3D11VA is the modern hardware acceleration API for Windows.

Advantages:

• Best performance on Windows 10/11
• Efficient GPU memory management
• Supports modern codecs (H.265/HEVC, VP9, AV1)
• Lower latency than DXVA2

Requirements:

• Windows 10 or later
• DirectX 11 compatible GPU
• Updated graphics drivers

Supported Codecs:

• H.264/AVC
• H.265/HEVC
• VP9
• AV1 (on supported GPUs)

DXVA2 (DirectX Video Acceleration 2)

DXVA2 is the legacy hardware acceleration API, maintained for compatibility.

Advantages:

• Works on Windows 7 and later
• Broad GPU support
• Stable, well-tested implementation

When to Use:

• Windows 7/8 systems
• Older graphics cards
• When D3D11VA causes issues
• Virtual machines with limited GPU passthrough

Supported Codecs:

• H.264/AVC
• MPEG-2
• VC-1

Software Decoding (None)

Disables GPU acceleration entirely, using CPU for all decoding.

When to Use:

• Troubleshooting GPU-related issues
• Systems with incompatible GPU drivers
• Testing or comparing performance
• Remote desktop scenarios

Trade-offs:

• Higher CPU usage (30-70% for 4K)
• May struggle with multiple videos
• Useful for isolating hardware problems

Choosing the Right Mode

Start with Auto (default)
         │
         ▼
    Working well? ──Yes──► Keep Auto
         │
         No
         ▼
    Try DXVA2
         │
         ▼
    Working well? ──Yes──► Use DXVA2
         │
         No
         ▼
    Use None (software)
    + Update GPU drivers

Performance Settings

Video Buffer Size

Controls how many frames are buffered ahead of playback.

Setting	Frames	Effect
Low	2-4	Less memory, may stutter on slow disks
Normal	8-12	Balanced (default)
High	16-24	Smoother playback, more memory usage

Increase buffer size if experiencing stuttering with high-bitrate content.

Decode Thread Count

Number of CPU threads used for software decoding operations.

Setting	Description
Auto	Uses all available cores
Manual	Specify exact thread count

Leave on Auto unless you need to reserve CPU cores for other applications.

Synchronization Settings

Duration Tolerance (DurationToleranceMs)

Controls how closely video durations must match to sync together.

Value	Effect
50ms	Strict - only nearly identical durations sync
100ms	Normal (default) - standard tolerance
200ms	Loose - more videos will sync together

Lower values ensure only intentionally matching videos sync. Higher values are more forgiving of export variations.

Auto Sync Same Duration (AutoSyncSameDuration)

Setting	Behavior
Enabled	Videos with matching duration automatically sync (default)
Disabled	All videos play independently

Disable if you have same-length videos that should NOT sync together.

Sync Check Interval

How frequently MultiMon checks and corrects sync drift.

Interval	Use Case
16ms	Most responsive (default, ~60 checks/second)
33ms	Reduced CPU overhead
50ms	Minimal overhead, may allow more drift

Leave at default unless CPU usage is a concern.

Display Settings

Fullscreen Mode

Option	Behavior
Exclusive	Takes full control of display (best performance)
Borderless	Fullscreen window (allows alt-tab, overlays)

Exclusive mode provides the smoothest playback but prevents switching applications without exiting Perform Mode.

VSync

Setting	Effect
Enabled	Syncs to monitor refresh rate, prevents tearing
Disabled	Lowest latency, may show tearing

Keep enabled unless you have specific latency requirements.

Monitor Refresh Rate

MultiMon respects your Windows display settings. For best results:

1. Set monitors to their native refresh rate
2. Match video frame rate to monitor refresh when possible
3. 60Hz monitors work well with 24/30/60 fps content

Audio Settings

Audio Device Selection

Choose which audio device receives output:

• Default - Uses Windows default device
• Specific Device - Select a particular output

Changes take effect immediately.

Audio Buffer Size

Size	Latency	Stability
Small	~20ms	May crackle under load
Normal	~50ms	Balanced (default)
Large	~100ms	Most stable, noticeable delay

Increase if experiencing audio crackling; decrease for lower latency in interactive scenarios.

For advanced audio configuration, see Audio Mixer & Routing.

File Associations

Project File Types

Extension	Description	Double-Click Behavior
.mmproj	Full project file	Opens in editor mode
.mmplay	Quick Perform file	Opens and auto-starts Perform Mode

Enabling File Associations

Enable associations to double-click project files to open them in MultiMon:

1. Open Settings → File Associations
2. Check the file types you want to associate
3. Click Apply (may require administrator privileges)

Quick Perform Auto-Launch

When .mmplay files are associated:

• Double-clicking launches MultiMon directly into Perform Mode
• Videos begin playing immediately on their assigned monitors
• Press Escape to exit to the main interface
• Ideal for show operators who just need to start playback

This behavior makes .mmplay files perfect for creating desktop shortcuts or scheduled tasks for automated playback.

For more details on Quick Perform files, see the Quick Perform Files guide.

Settings Storage

Settings are stored in your user profile:

%APPDATA%\Local\MultiMon\settings.json

Backup and Restore

To backup your settings:

1. Navigate to the settings folder
2. Copy settings.json
3. Store in a safe location

To restore:

1. Close MultiMon
2. Replace settings.json with your backup
3. Relaunch MultiMon

Reset to Defaults

To reset all settings:

1. Close MultiMon
2. Delete settings.json
3. Relaunch - defaults will be recreated

Troubleshooting

Hardware Acceleration Issues

Symptom: Black screen, crashes, or artifacts

Solutions:

1. Update GPU drivers to latest version
2. Try switching from D3D11VA to DXVA2
3. If both fail, use None (software decoding) temporarily
4. Check Windows Event Viewer for GPU errors

High CPU Usage

With hardware acceleration enabled:

• Verify GPU is being used (check Task Manager GPU usage)
• Try different acceleration mode
• Update GPU drivers

With software decoding:

• Expected behavior - consider enabling hardware acceleration
• Reduce video resolution or use HAP codec

Sync Drift

If videos drift apart over time:

1. Verify videos have matching durations (within tolerance)
2. Check DurationToleranceMs setting
3. Convert to HAP format for most consistent timing
4. Ensure videos are constant frame rate (CFR)

Audio Latency

If audio is delayed:

1. Reduce audio buffer size
2. Check for system audio enhancements (disable them)
3. Verify audio device sample rate matches content

Recommended Settings by Use Case

Live Events / Installations

Hardware Acceleration: Auto
VSync: Enabled
Fullscreen Mode: Exclusive
Buffer Size: High
Audio Buffer: Normal

Development / Testing

Hardware Acceleration: Auto
VSync: Enabled
Fullscreen Mode: Borderless
Buffer Size: Normal
Audio Buffer: Normal

Low-End Hardware

Hardware Acceleration: Auto (or DXVA2)
VSync: Enabled
Buffer Size: Low
Decode Threads: Auto

Use HAP codec for best performance on limited hardware.

Keyboard Reference

Key	Action
F5	Refresh devices (re-detect monitors and audio)
F11	Enter Perform Mode
Escape	Exit Perform Mode / Close dialogs