foo_vis_milk2 Manual

foo_vis_milk2 is a DirectX 11.1 music visualizer component for foobar2000, based on the MilkDrop 2 engine. It renders real-time visual effects driven by audio input, using HLSL shaders and a per-frame expression evaluation system. foo_vis_milk2 supports x86, x64, ARM64 and ARM64EC architectures.

Getting Started

1. Install foobar2000 (v2.0 or later).
2. Download foo_vis_milk2.fb2k-component from the component page or GitHub Releases.
3. Import foo_vis_milk2.fb2k-component via File > Preferences > Components > Install...
4. Restart foobar2000 when prompted.
5. The visualizer appears as a panel in the Default UI or Columns UI layout. Right-click a panel and select Visualizations > MilkDrop 2 to add it.

Once running, the visualizer receives audio and metadata directly from foobar2000's playback pipeline. Play music and visuals respond automatically.

Press F1 for the built-in help overlay.

System Requirements

• Windows 10 or later (Windows 11 recommended)
• DirectX 11.1 compatible GPU
• foobar2000 v2.0 or later

Some features such as hybrid graphics, high DPI displays, and HDR may require a newer DXGI version than what is available on the system.

Window Modes

Keyboard Shortcuts

Note: keyboard shortcuts assume the MilkDrop visualization window is focused, and that foobar2000 or the operating system has not reassigned the same key combinations as global/application hotkeys.

Preset Navigation

Visual Controls

Waveform

Video Echo (MilkDrop 1 Presets Only)

Shaders

Display Info

Sprites & Messages

Music Playback

General

Mouse and Context Menu

File Drag and Drop

You can drag and drop exactly one file onto the visualization window at a time:

• .milk or .milk2: loads the dropped preset.
• Supported image files: launches the dropped image as a runtime sprite.

Supported image extensions for drag and drop are: .png, .jpg, .dds, .bmp, .tga, .jpeg, .jfif, .dib, .tiff, .tif, .webp, .gif, and .avif.

Context Menu Commands

Right-clicking the visualization (or pressing the Context Menu key) opens a popup menu with runtime controls.

Preferences

Open File > Preferences > Visualization > MilkDrop 2 to configure the component. Settings are stored in foobar2000's preferences system rather than INI files.

Preset Management

Transitions and Timing

Hard Cuts (Beat Detection)

Hard-Cut Modes (F11 / SHIFT+F11)

Press F11 (or SHIFT+F11 to go backward) to cycle hard-cut modes.

Notes:

• Modes 2-12 use mode-specific beat triggers and internal thresholds.
• The Time between hard cuts and Hard cut loudness threshold settings primarily affect Mode 1 (Normal) behavior.

Song Title and Messages

Audio Analysis

Graphics and Rendering

Image Cache

Windowed Mode

Miscellaneous

Advanced Preferences

Open File > Preferences > Advanced > Visualization > MilkDrop 2 to access advanced settings.

Presets

Presets are .milk files that define visual behavior through per-frame equations, per-pixel equations, custom shapes, custom waves, and HLSL shaders. foo_vis_milk2 is compatible with the MilkDrop 2 preset ecosystem.

Loading Presets

• Press L to open the preset load dialog
• Press SPACE to load a random preset with a soft blend
• Press H for a hard cut to the next preset
• Press BACKSPACE to return to the previous preset (64-deep history)
• Press A for a mashup that combines shaders from multiple presets

Preset Transitions

• SPACE: Soft blend to the next preset (uses the configured blend time)
• H: Hard cut (instant switch)
• Beat-driven hard cuts trigger automatically based on audio energy (configurable)
• 18 transition blend patterns available, cycled with ? and /

Transition Blend Patterns

The visualizer supports 18 blend patterns for smooth preset transitions, including:

• Random
• Fade
• Directional wipe
• Plasma
• Radial
• Clock
• Spiral/snail
• Rhombus/diamond
• Nuclear clock
• Checkerboard wipe
• Curtain
• Bubble

Preset Lock

Press SCROLL LOCK to lock the current preset, preventing auto-advance and random selection.

Preset Rating

Press + or - to rate the current preset. Ratings are stored as fRating inside the [preset00] section of each .milk file (float, 0.0–5.0). When random mode uses weighted ratings (optional), higher-rated presets appear more frequently.

Recursive mode and ratings: When recursive subdirectory scanning is enabled, the rating system is effectively disabled. Reading the fRating value from every .milk file in a deep directory tree would be too slow, so recursive mode assigns a hardcoded rating of 3.0 to all presets. To use per-preset ratings, disable recursive scanning.

Preset Directory

Default location: <foobar2000 profile>\milkdrop2\presets

Configure via File > Preferences > Visualization > MilkDrop 2. Subdirectories are scanned recursively (optional).

Last Directory and Preset Restore

foo_vis_milk2 persists two related values per UI instance:

• Last preset directory (m_szPresetDir)
• Last preset filename (m_szLastPreset)

Save behavior on close/layout save:

• The current preset directory is always saved.
• The current preset filename is saved only when Start with preset lock ON is enabled and a valid current preset is active.
• If startup lock is off, the saved last preset filename is cleared.

Restore behavior on next launch:

• The saved preset directory is restored first.
• If the restored directory is empty or no longer valid, the component falls back to the Advanced Preferences base preset directory.
• On initial preset selection:
  • If preset lock is enabled and a saved last preset filename exists, that preset is loaded from the restored directory.
  • Otherwise, normal startup selection applies (schedule-driven first, then random if no schedule row is available).

Practical note:

• To reliably resume the same preset on startup, enable Start with preset lock ON before closing foobar2000.

Preset Editing

Press M to open the preset editing menu. Each editable section of the running preset is listed as a menu item. Navigate with UP / DOWN and press RETURN to enter text editing mode (called a "waitstring").

Editable Sections

Waitstring Controls

What Happens on Commit

When you commit an edit (CTRL+ENTER for code, RETURN for non-code strings):

1. The edited text is copied back into the in-memory preset state (m_pState).
2. A callback recompiles the affected section:
   • EEL code (equations): RecompileExpressions() runs under a critical section lock. The new expressions take effect immediately.
   • HLSL shaders (warp/composite): RecompilePShader() compiles the new shader. If compilation fails, a fallback shader is substituted automatically and an error message is displayed.
3. The visualization reflects the change on the next frame.

In-Memory Only

Edits are applied to the running preset state only and are not saved to disk. Changes are lost when:

• A different preset loads (auto-advance, random, or manual)
• The visualizer restarts or foobar2000 exits

To persist changes, explicitly save the preset:

• S: Save overwrite (writes to the current .milk file)
• SHIFT+S: Save as (prompts for a new filename)

Editing During a Blend Transition

During a preset transition (two presets blending), the menu shows the incoming (new) preset, not the outgoing one. Internally, m_pState is swapped to point at the new preset when the blend begins:

• Menu values: Show the new preset's unblended parameters (the blend target).
• Rendered output: Still shows the blended interpolation between old and new.
• Edits: Modify the new preset and recompile immediately, even while the blend is in progress.

The same applies to .milk2 double-preset files — the blend-to sub-preset becomes m_pState.

Limits

• Code buffers have a hard maximum of approximately 8,190 characters. Input beyond this limit is silently truncated.
• The cursor position is remembered per menu item between editing sessions.

Preset Scheduling

Place a preset_order.csv (CSV with header row) or playlist.txt in the active preset directory to define a custom playback order (and optional per-preset FPS caps). When present, the visualizer reads the file to schedule presets instead of using random or sequential selection. The CSV is parsed by the external csv-parser library.

Preset Schedule CSV

Schema (header row required):

• preset (required): preset filename relative to the preset directory, for example MyPreset.milk.
• duration (required): seconds to stay on this preset. Must be > 0.
• blend (optional): blend time in seconds for this transition. If omitted, the normal auto-blend setting is used.
• fps (optional): max FPS override for this row.
  • 0 means unlimited.
  • 1..200 sets that exact max FPS.
  • Empty or out-of-range values leave FPS unchanged (default setting).

Additional behavior:

• duration = inf (or equivalent positive infinity) locks that preset (no automatic advance).
• Rows with missing files are skipped when advancing.
• At the end of the list, the schedule loops back to the first row.
• If no valid rows are loaded, normal library/random order behavior is used.

Example:

preset,duration,blend,fps
martin - lonely goose.milk,90,1.5,60
Stahlregen - Simple Spectrum (together).milk,45,,0
Flexi - wolfram's rule 90 [rise of the log attack].milk,inf,0.8,30

Audio

foo_vis_milk2 receives audio directly from foobar2000's playback engine as floating-point audio_sample values — no audio routing or virtual cables are needed.

Precision by target architecture:

• x86: audio_sample is 32-bit single-precision (float).
• x64 / ARM64 / ARM64EC: audio_sample is 64-bit double-precision (double).

Multichannel Mixing

foo_vis_milk2 normalizes incoming audio to two waveform channels before analysis/rendering:

• Stereo input: passed through as left/right.
• Mono input: duplicated to both channels.
• Multichannel input: downmixed to stereo using channel-map-aware dB-weighted gains.

Mixing notes:

• Left-only channels feed left, right-only channels feed right.
• Center-class channels (including center/LFE/top-center variants) feed both channels.
• Typical gains are attenuated relative to front left/right; for example, center is reduced and LFE is heavily reduced.
• During downmix, audio_sample input values are converted to float and accumulated into float waveform buffers.
• Final waveform values are scaled to the legacy MilkDrop amplitude range used by the renderer.

Audio Analysis

• Waveform buffer: 576 samples per frame (480 used for rendering)
• FFT: 512 frequency bins
• Frequency bands: Bass, mid, and treble with both immediate and attack-smoothed values

Playback Transport Behavior

• Playing: waveform data is updated from the visualization stream as usual.
• Paused: the last waveform is held steady (no decay), so visuals do not jump when pausing.
• Stopped: waveform buffers decay smoothly toward silence instead of snapping to zero.

Preset Audio Variables

Messages

The message system displays user-defined text overlays on screen. Messages are defined in milk2_msg.ini (located in milkdrop2\) with up to 100 message slots (00–99) and up to 16 font definitions (00–15). The maximum file size is 64 KB.

Using Messages at Runtime

1. Press Y to enter custom message mode.
2. Type the two-digit code (00–99) of the message to display.
3. If the first digit is wrong, press BACKSPACE to start over.
4. Press F7 (while in message mode) to reload milk2_msg.ini from disk without restarting.

File Format

Both milk2_msg.ini and milk2_img.ini are parsed by the Windows GetPrivateProfileString() API. The only officially recognized comment prefix is ; (semicolon) at the start of a line. Lines beginning with // are tolerated because the API silently skips lines that are not valid [section] headers or key=value pairs, but ; is the recommended comment style.

All parameters have defaults and can be omitted, except for the text field of each message.

Font Definitions

Fonts are defined in [font##] sections (where ## is 00–15). Messages reference fonts by their ID and can optionally override individual font properties.

Message Definitions

Messages are defined in [message##] sections (where ## is 00–99).

Per-Message Font Overrides

Any message can override its referenced font's properties inline:

Example

[font00]
face=arial
bold=1
ital=0

[message00]
text=This is a test...
font=0
fade=0.4
time=1.2
size=50
growth=2.0
x=0.5
y=0.2

Sprites

Sprites are animated image overlays managed via milk2_img.ini (located in milkdrop2\). Each sprite has an image file, blend mode, position, scale, rotation, and programmable animation code using EEL expressions. Up to 16 sprites can be on screen simultaneously, and up to 100 sprite definitions (00–99) can exist in the file.

The file uses the same INI comment conventions as milk2_msg.ini: lines starting with ; are comments (see File Format above).

Supported Image Formats

Use .jpg for automatic extension probing. Explicit img= paths can also use .jpeg/.jfif when supported by WIC codecs.

Image File Paths

The img= line is mandatory. Paths can be relative or absolute:

Texture Memory Notes

• Textures can be up to 2048×2048 and do not need to be square.
• Dimensions in memory are rounded up to the next power of two (e.g., 500×60 becomes 512×64).
• Large textures consume significant video memory and reduce frame rate. 256×256 is recommended; 512×512 maximum.
• If video memory is insufficient, the texture is downsampled (as low as 16×16) to fit.
• The sprite manager supports instancing: multiple sprites using the same image share a single texture in memory.
• Textures are freed immediately when all sprites referencing them expire.

Using Sprites at Runtime

Sprite Code

Each sprite definition has init code (init_1, init_2, ...) that runs once at launch, and per-frame code (code_1, code_2, ...) that runs every frame. All mathematical functions available in MilkDrop preset equations are available in sprite code.

Custom variables can be defined in init code by assigning a value. They persist across frames and can be read/modified in per-frame code.

Read-Only Variables

Read/Write Variables

Blend Modes

Set blendmode in init code to control how the sprite composites onto the screen.

Color Key Details

When blendmode = 4, a colorkey line is required:

colorkey=0x000000

The value is a 24-bit hexadecimal color (0xRRGGBB):

• 0x000000 — black is transparent
• 0xFFFFFF — white is transparent
• 0x0000FF — blue is transparent

The alpha value (a) still modulates overall sprite opacity when using color keying. This mode works best in 32-bit color.

Embedded Sprites

Presets can reference embedded sprites that load automatically when the preset is active. Toggle auto-loading with CTRL+L.

Auto-load compatibility is enabled for .milk2 presets and for compatible MilkDrop 3 preset states.

Example

[img04]
desc="An object drifts across the screen periodically."
img=textures\smalltiled_electric_nebula.jpg
init_1=blendmode = 3;
init_2=x = -100;
init_3=orig_y = 0.5;
code_1=time_to_reset = below(x,-0.5);
code_2=x = x*(1-time_to_reset) + time_to_reset*(1.5 + 0.01*rand(100) + 3);
code_3=orig_y = orig_y*(1-time_to_reset) + time_to_reset*(0.3 + 0.4*0.01*rand(100));
code_4=sx = sx*(1-time_to_reset) + time_to_reset*(0.25 + 0.4*0.01*rand(100));
code_5=sy = sx;
code_6=x = x - 0.008 + 0.0033*sin(time*1.371);
code_7=y = orig_y + 0.12*sin(time*1.9);

Track Info

foo_vis_milk2 displays current track information using foobar2000's title format system. The format string is configurable in preferences.

Displayed information includes:

• Song title (F2)
• Song length (F3)
• Preset name (F4)
• FPS counter (F5)
• Preset rating (F6)

Custom Shapes

Presets support up to 16 custom shapes with EEL expression-based definitions:

• Init code: Runs once when the preset loads
• Per-frame code: Runs every frame to update shape parameters
• Per-vertex code: Runs for each vertex of the shape

Shapes are drawn into the render target with alpha blending or additive blending.

Custom Waveforms

Presets support up to 16 custom waveforms with:

• Spectrum mode: Renders frequency data instead of waveform
• Drawing modes: Lines, dots, thick lines
• Additive blending: Bright-on-dark compositing
• Per-point code: EEL expressions for per-sample manipulation

Exporting Waves and Shapes

Custom wave and shape definitions can be exported as standalone files from the in-app menu:

• Custom wave export writes a .wave file (default path: milkdrop2\waves\file.wave)
• Custom shape export writes a .shape file (default path: milkdrop2\shapes\file.shape)

These exports are useful for reusing wave/shape definitions across presets or sharing them independently.

Screenshots

• PRINT SCREEN, CTRL+F12, or CTRL+Left Click: Saves a PNG screenshot
• Output directory: milkdrop2\screenshots\

Preset Variables

Read-Only Variables

Read/Write Variables

IPC

foo_vis_milk2 supports inter-process communication via the WM_MILK2 window message for external control:

Files and Directories