SneakPeak

Precision waveform item editor for REAPER - a native C++ extension that gives you a detailed, dockable waveform view for any media item. Click an item in REAPER's arrange view, and SneakPeak instantly shows you a full-featured waveform editor with dynamics processing, volume envelope editing, spectral analysis, multi-item layering, and real-time metering. Available for macOS (arm64/x86_64), Windows (x64), and Linux (x86_64/aarch64).

Select any audio item in REAPER and get an instant, detailed waveform with dynamics processing, volume envelope editing, spectral analysis, multi-item layering, and real-time metering - all in a dockable window.

Screenshots

Standalone editing	Multi-item layered view

Spectral analysis	Minimap navigation

Fade handles with continuous curvature

Dynamics with GR shading	Live mode with envelope

Dynamics panel

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Why SneakPeak?

REAPER is the most powerful DAW on the market, but a detailed waveform item editor has always been the one thing missing. SneakPeak fills that gap - a dedicated editor that lives inside REAPER as a native extension.

I looked everywhere for a solution - scripts, extensions, workarounds - but nothing delivered what I needed. So I built it. After months of development, I'm releasing SneakPeak as a free, open-source extension for the REAPER community. I considered making it paid, but ultimately decided that the community deserves access to tools like this without barriers.

If you find SneakPeak valuable, please consider supporting its development. Every contribution helps keep this project alive and growing.

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Features

SneakPeak has five viewing modes: ITEM (default - click any item), Timeline View (after cutting), Multi-Item (select 2+ items), SET (working set, press T), and Standalone (drag & drop files). All non-destructive editing goes through the REAPER API with full undo.

Waveform Display

• Precision waveform rendering - Peak + RMS display with dB scale, clip indicators, and zero-crossing line.
• Deep zoom - Horizontal and vertical zoom with scroll wheel, toolbar buttons, and keyboard. Zoom to fit, zoom to selection.
• Minimap - Resizable overview bar showing the full item waveform. Click to navigate, drag to scroll.
• Time ruler - Dynamic tick intervals from milliseconds to minutes with position readout.
• Channel controls - Per-channel visibility (L/R mute buttons), mono downmix toggle.

Audio Editing

• Precision selection - Click and drag to select audio regions. Shift+click to extend. Double-click to select all.
• Cut / Copy / Paste - Full clipboard support with sample-accurate editing.
• Normalize - Peak normalization to 0 dB, plus LUFS normalization (-14 / -16 LUFS).
• Fades - Drag fade handles with continuous curvature control (horizontal = length, vertical = curve shape). 7 base shapes with smooth curvature matching REAPER's native D_FADEINDIR.
• Reverse - Reverse selection or full item.
• Gain adjustment - Interactive gain knob (+24 to -60 dB) with fine-adjust mode (Cmd+drag). Scroll wheel on knob for +/-0.5 dB. Quick +3/-3 dB from context menu.
• DC offset removal - One-click DC bias correction.
• Silence / Insert silence - Zero out selection or insert silence at cursor.
• Snap to zero-crossing - Intelligent selection boundaries at zero-crossing points.
• Undo - Full REAPER undo integration. Independent 20-level undo stack in standalone mode.

Dynamics Processing

Right-click > Process > Dynamics Panel. SneakPeak auto-activates the take volume envelope if it isn't already enabled (no manual setup). Analyzes audio and writes volume envelope automation - zero CPU cost during playback.

• Built-in compressor - Industry-standard gain-smoothing architecture (ratio, threshold, soft knee, attack, release, auto makeup gain). Matches FabFilter Pro-C / Waves / ReaComp.
• Noise gate - Post-compression gate for breath reduction in speech/podcast. Threshold, range, hold parameters.
• Lookahead - 0-20ms transient detection without latency cost.
• 10-slider dynamics panel - Inline control surface with real-time preview. Any slider change instantly updates the compression curves on the waveform.
• Live mode - Real-time envelope writing as you drag sliders. Waveform updates instantly, no Apply needed.
• 6 built-in presets - Default, Gentle Leveling, Voice/Podcast, Broadcast, De-breath, Music Bus.
• Per-item persistence - Settings auto-saved via P_EXT, auto-loaded when reopening.
• GR meter + shading - Gain reduction visualization in panel and on waveform.
• A/B bypass - Instant before/after comparison (audio + visual).
• Peak/RMS detection - Toggle between peak and RMS analysis modes.

Volume Envelope Editing

Enable via right-click > View > Show Volume Envelope. SneakPeak auto-activates the take volume envelope on the current item if it is not yet enabled in REAPER.

• Envelope overlay - Cyan curve showing take volume envelope, 1:1 with REAPER arrange view.
• Point editing - Click to add, drag to move, double-click or Delete to remove. Right-click for curve shape (6 shapes).
• Multi-select - Shift+click to toggle, batch drag/delete.
• Freehand drawing - Cmd+drag on envelope line to draw points continuously.
• Selection rectangle - Cmd+drag on empty area for rectangle selection.
• Dense point interaction - Reveal rectangle for managing >100 points after Apply Dynamics.
• Works in all modes - ITEM, Timeline, and SET modes via per-segment envelope lookup.

Spectral Analysis

• Real-time spectrogram - Async FFT computation (2048-point) with magma color scheme.
• Frequency selection - Alt+drag to select frequency bands for visual isolation.
• Per-channel display - Stereo spectral view with stacked channels.

Timeline View

Enters automatically after cutting an item in ITEM mode. Shows all fragments with gaps preserved. Exit by clicking a single item. Also accessible via the MULTI dropdown menu.

• Post-cut continuity - All surviving fragments shown with gaps preserved, matching the REAPER timeline 1:1. Dark background marks gap regions.
• Repeated editing - Continue cutting, adjusting gain, and editing within timeline view. Zoom position preserved across operations.
• Auto lifecycle - Enters automatically after cut, exits when you click a single item on REAPER timeline.
• Option+click segment snap - Option+click on any segment to instantly select its full range for gain adjustment without creating new splits.

Multi-Item View

Select 2+ items in REAPER to enter automatically. Click the MULTI label for a dropdown to switch between Mix, Layered, and Timeline View.

• Cross-track editing - View all selected items together on an absolute timeline.
• Mix mode - Sum all items into a single waveform (like a folder track).
• Layered mode (per Item) - Each item displayed in a distinct color with transparency, overlaid on each other. 8-color palette for clear visual separation.
• Layered mode (per Track) - Items colored by their parent track for track-aware visualization.
• Gap visualization - Dark regions between items for clear visual context.
• Cross-segment editing - Delete and gain operations work across item boundaries.
• Crossfade indicators - Join-point lines at crossfade midpoints for easy visual reference.
• Batch gain - One knob adjusts relative gain across all selected items.

Working Set (SET Mode)

Select items on one track, press T to enter. Gaps collapse into a continuous waveform. Press T again or Escape to exit.

• Lock items for editing - Persistent Working Set survives clicking elsewhere. Click any set item to restore.
• Persistent state - Click elsewhere and come back - the set auto-restores when you click any set item.
• Non-destructive editing - Delete, split, and gain operations work through REAPER API with full undo.
• Ripple edit - Delete in SET mode automatically pulls subsequent items left to close gaps.
• Selection-aware gain - Gain knob with selection splits at edges and applies D_VOL only to the fragment (with 10ms crossfade overlap).
• Group Set Items - Group all items in the set (or selected range) for easy timeline manipulation. Visual colored bar below ruler.
• Clipping visualization - Peaks above 0dB draw in red, proportional to severity.
• Absolute time ruler - Toggle between relative and REAPER timeline time (context menu).
• Bidirectional cursor sync - Click in SneakPeak scrolls REAPER arrange, click on REAPER timeline updates SneakPeak playhead.

Metering

• Real-time level meters - Stereo L/R display with peak hold indicators.
• Three meter modes (right-click to switch):
  • Peak (PPM) - True peak metering, instant attack, slow decay.
  • RMS (AES/EBU) - RMS loudness with 300ms integration window.
  • VU - Classic VU ballistics with slow attack and decay.
• Info panel - Selection bounds, view range, format details (sample rate, bit depth, channels, file size, duration).

Standalone File Mode

Drag any audio file (WAV, MP3, FLAC) into the SneakPeak window to enter. Fully destructive editing with independent undo.

• Drag & drop files directly into SneakPeak for offline editing.
• Multiple file tabs - Up to 8 files open simultaneously with independent undo stacks.
• Smart Save - Ctrl+S with overwrite confirmation for WAV, auto _edit.wav for MP3/FLAC. Ctrl+Shift+S for Save As.
• Replace Source in REAPER Timeline - Right-click > Replace Source in REAPER Timeline after editing: one click saves the file and swaps P_SOURCE on every project take that references the original path. Immediate arrange redraw.
• Drag-export - Drag files to REAPER timeline. Clean files use original (no copy), dirty files auto-save first. Selections export as named WAV.

Markers

• Add markers at cursor position (M key).
• Add regions from selection (Shift+M).
• Edit / delete / drag markers in the ruler.
• Tab / Shift+Tab to navigate between markers.

Playback

• Play from cursor or play selection with REAPER transport.
• Playhead follow - Waveform auto-scrolls to follow playback position.
• Standalone preview - Play audio directly from standalone tabs.

Integration

• Floating or docked - Starts as resizable floating window. Dock/undock via context menu ("Dock SneakPeak in Docker"). Position and size remembered across sessions.
• Auto-follow selection - Automatically loads the selected item when you click in the arrange view.
• Drag export - Drag a selection outside SneakPeak to place it on REAPER timeline. Alt+drag for immediate export to Finder.
• Track solo - Solo button (S) for quick track isolation.
• REAPER markers - Full integration with REAPER's project markers.
• Persistent settings - All preferences (meter mode, view mode, minimap, snap, dock state, RMS/meter visibility) survive REAPER restarts.
• Check for updates - Click the version label in the mode bar to query the latest release on GitHub.
• Hide RMS / hide meters - View menu toggles to show peak-only waveforms or give the waveform the full vertical space.

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Keyboard Shortcuts

Action	Shortcut
Play / Pause	Space
Stop	Escape
Jump to start	Home
Jump to end	End
Next marker	Tab
Previous marker	Shift+Tab
Select all	Ctrl/Cmd+A
Undo	Ctrl/Cmd+Z
Cut	Ctrl/Cmd+X
Copy	Ctrl/Cmd+C
Paste	Ctrl/Cmd+V
Delete selection	Delete or E
Silence / Insert silence	Ctrl/Cmd+Delete
Normalize	Ctrl/Cmd+N
Toggle gain panel	G
Add marker	M
Add region	Shift+M
Save (standalone)	Ctrl/Cmd+S
Save As (standalone)	Ctrl/Cmd+Shift+S
Split at cursor	S
Ripple Delete	Shift+Delete or Shift+E
Gain +/-1 dB	Up / Down
Next/Previous segment	Alt/Option+Right/Left
Zoom	Scroll wheel
Vertical zoom	Shift+Scroll or Alt+Scroll
Pan	Ctrl/Cmd+Scroll
Fine-adjust gain	Ctrl/Cmd+drag on knob

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Installation

ReaPack (recommended)

1. In REAPER, go to Extensions > ReaPack > Import repositories...
2. Paste this URL:

   https://raw.githubusercontent.com/b451c/SneakPeak/main/index.xml
   

3. Go to Extensions > ReaPack > Browse packages, search for SneakPeak.
4. Right-click > Install, then restart REAPER.

ReaPack will automatically notify you of future updates.

Troubleshooting: if Synchronize packages does not show the latest version after a new release, check these in order:

1. URL path in ReaPack > Manage repositories... must contain /main/, not /testing/. Testing-branch URLs from alpha/beta periods serve an independent index that does not track production releases.
2. Cache file mtime - after Synchronize, ~/Library/Application Support/REAPER/ReaPack/Cache/SneakPeak.xml (or your platform's equivalent) should be freshly updated. If it's stale, the download is silently failing to write (permissions, AV quarantine, disk). Remove and re-add the repo - this deletes and rewrites the cache file.
3. Corporate proxy or AV may strip Cache-Control: no-cache and serve a cached copy. Verify with curl -H 'Cache-Control: no-cache' https://raw.githubusercontent.com/b451c/SneakPeak/main/index.xml - should return the current index.
4. Fresh release (<5 min ago) - GitHub raw CDN (raw.githubusercontent.com via Fastly) returns Cache-Control: max-age=300. Wait 5 minutes and retry. Does not apply once more than 5 minutes have elapsed.

Manual install

1. Download the binary for your platform from the Releases page.
2. Copy it to your REAPER UserPlugins folder:

Platform	File	Path
macOS arm64	reaper_sneakpeak-arm64.dylib	~/Library/Application Support/REAPER/UserPlugins/
macOS x86_64	reaper_sneakpeak-x86_64.dylib	~/Library/Application Support/REAPER/UserPlugins/
Windows x64	reaper_sneakpeak-x64.dll	%APPDATA%\REAPER\UserPlugins\
Linux x86_64	reaper_sneakpeak-x86_64.so	~/.config/REAPER/UserPlugins/
Linux aarch64	reaper_sneakpeak-aarch64.so	~/.config/REAPER/UserPlugins/

3. Restart REAPER.
4. Open via Actions > SneakPeak: Toggle Window, or assign a keyboard shortcut.

macOS note: Only install one dylib - having both arm64 and x86_64 in UserPlugins will cause REAPER to load both and crash.

Build from source

See Building below.

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Usage

1. Open SneakPeak - Run "SneakPeak: Toggle Window" from REAPER's Actions menu (or assign a shortcut).
2. Click any audio item in REAPER's arrange view - SneakPeak instantly shows the detailed waveform.
3. Click and drag on the waveform to make a selection. Shift+click to extend.
4. Right-click anywhere for the full context menu - editing, processing, view options.
5. Use the toolbar for zoom, transport, and audio processing.
6. Toggle spectral view from the context menu (View > Spectral View).
7. Select multiple items to enter multi-item mode. Right-click > View > Multi-Item View to switch between Mix and Layered modes.
8. Right-click the meter panel (bottom) to switch between Peak, RMS, and VU metering.
9. Drag a WAV file onto the window to open it in standalone mode.
10. Press G to show the gain knob for non-destructive level adjustment.

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Building

Prerequisites

• CMake 3.15+
• C++17 compiler (Clang on macOS)
• REAPER SDK - clone into sdk/:

  git clone https://github.com/justinfrankel/reaper-sdk.git sdk

• WDL - clone into WDL/:

  git clone https://github.com/justinfrankel/WDL.git WDL

Compile and install (macOS)

mkdir -p build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make -j$(sysctl -n hw.ncpu)
cp reaper_sneakpeak.dylib ~/Library/Application\ Support/REAPER/UserPlugins/

Debug build

Debug builds enable verbose logging to /tmp/sneakpeak_debug.log:

cmake .. -DCMAKE_BUILD_TYPE=Debug
make -j$(sysctl -n hw.ncpu)

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Requirements

• REAPER 7.0+ (tested on 7.62+)

Supported Platforms

Platform	Architecture	Status
macOS	arm64 (Apple Silicon)	Stable (primary development)
macOS	x86_64 (Intel)	Stable
Windows	x64	Stable
Linux	x86_64	Stable
Linux	aarch64	Stable

All platforms built via GitHub Actions CI on every tagged release. The codebase is pure C++ with WDL/SWELL - zero external dependencies.

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Architecture

src/
  main.cpp                Entry point, REAPER API imports, action registration
  edit_view.h/cpp         Core: window lifecycle, timer, layout, message dispatch
  rendering.cpp           Paint routines, mode bar, ruler, dynamics curves, master waveform
  input_handling.cpp      Mouse, keyboard, toolbar, envelope editing dispatch
  audio_commands.cpp      Clipboard, undo, destructive editing, normalize, fade, reverse
  standalone_file.cpp     Standalone tab lifecycle, save/load/save-as, preview playback
  context_menu.cpp        Right-click menu construction and command dispatch
  drag_export.cpp         Drag & drop WAV export to timeline/desktop
  waveform_view.h/cpp     Waveform data, zoom, selection, envelope helpers, coordinates
  waveform_rendering.cpp  Peak computation, waveform + envelope drawing, dB scale, fades
  dynamics_engine.h/cpp   Compressor + gate computation (peak/RMS, attack/release, lookahead)
  dynamics_panel.h/cpp    Inline dynamics control panel (10 sliders, presets, Live mode)
  item_split_ops.h/cpp    SplitAndApplyGain helper for consistent gain across all modes
  toolbar.h/cpp           Button bar with zoom, transport, and editing actions
  audio_engine.h/cpp      WAV file I/O (16/24/32-bit float), REAPER source refresh
  audio_ops.h/cpp         Sample processing (normalize, fade, reverse, gain, DC remove)
  multi_item_view.h/cpp   Mix/Layered multi-item view, per-layer audio, absolute timeline
  spectral_view.h/cpp     Async FFT spectrogram with magma colormap
  minimap_view.h/cpp      Resizable minimap overview
  levels_panel.h/cpp      Peak/RMS/VU level meters with mode-dependent ballistics
  gain_panel.h/cpp        Interactive gain knob with fine-adjust mode
  marker_manager.h/cpp    REAPER marker integration (add, edit, delete, navigate)
  theme.h/cpp             Color palette, visual theming, cached fonts
  config.h                Layout constants, interaction parameters, shared utilities
  platform.h              Cross-platform abstraction (Win32/SWELL)
  globals.h/cpp           REAPER API function pointers and helpers

The extension loads full audio data via REAPER's AudioAccessor API for accurate waveform display and editing. Double-buffered GDI rendering ensures smooth, flicker-free display.

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Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

Bug reports, feature requests, and cross-platform testing help are all appreciated. Please use GitHub Issues to report problems or suggest new features.

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Support

SneakPeak is free and open source. If you find it useful in your workflow, please consider supporting its development - it makes a real difference and helps keep the project alive:

• Ko-fi
• Buy Me a Coffee
• PayPal

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License

MIT - Copyright (c) 2025-2026 b451c

Links

• Forum thread - https://forum.cockos.com/showthread.php?t=307499
• REAPER - https://www.reaper.fm
• ReaPack - https://reapack.com
• REAPER SDK - https://github.com/justinfrankel/reaper-sdk
• WDL/SWELL - https://github.com/justinfrankel/WDL