nullPlayer is a free open source macOS media player with some unique features
Skill Claude CodeCodex
The Library Browser ART-mode visualizer — 30 Core Image GPU effects that transform album artwork based on audio. Use when adding/editing visualizer effects, intensity, keyboard shortcuts, or the ART-mode lifecycle.
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The classic and modern Audio Analyzer windows — a Friture-style multi-pane analyzer (Scope, Levels, Spectrogram, Octave, Pitch, Delay), the stereo PCM path that feeds them, per-pane consumer gating, and the shared AudioAnalysisDSP module. Use when modifying either analyzer window, its panes, the spectrogram shader, or…
Skill Claude CodeCodex
Audio engine architecture, local/streaming pipelines, EQ, spectrum analysis, and playback flow. Use when working on audio playback, streaming, equalization, spectrum visualization, BPM detection, or ProjectM integration.
Skill Claude CodeCodex
Implementation and maintenance guide for NullPlayer's standalone and embedded Cava spectrum analyzers, including DSP, rendering, scoped settings, skin-following colors, resets, UI-family switches, and window lifecycle.
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Google Cast Protocol v2, message framing, debugging, and test scripts. Use when working on Chromecast casting, debugging Cast protocol issues, or implementing Cast commands.
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Headless CLI mode for NullPlayer. Use when working on CLI features, arguments, playback control, query commands, source resolution, or terminal display. Covers architecture, all flags, keyboard controls, and source APIs.
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.cue sheet support — direct-play virtual split (open a .cue or an audio file with a sibling .cue → N playlist rows from one backing file, gapless) and library physical split-on-import (ffmpeg per-track files, off by default). Use when working on cue parsing, the AudioEngine cue boundary detector, in-file offset…
Skill Claude CodeCodex
Emby API, authentication flow, rating scale, streaming, scrobbling, and video playback. Use when working on Emby integration, library browsing, playback reporting, or video casting.
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Flow network throughput window — live download/upload meter, interface selection, single-height center-stack docking, classic/modern window controllers, and rendering behavior.
Skill Claude CodeCodex
Implementation reference for NullPlayer's Geiss visualization engine — the BSD-3-Clause port of Ryan Geiss's Win32/DirectDraw/Winamp-2 visualizer onto macOS as a ProjectM-peer engine. Covers the CGeissCore C ABI, upstream-vs-port file split, indexed-framebuffer + palette-LUT render pipeline, Accelerate-based spectrum…
Skill Claude CodeCodex
Per-mode shader and algorithm internals for the GPU visualization modes shared by both the main window and spectrum window — Fire, JWST, Lightning, Matrix, Snow, EKG. Includes Metal pass counts, audio mappings, color schemes, intensity presets, and the shader file names. Use when editing a specific mode's shader or…
Skill Claude CodeCodex
Jellyfin API, authentication flow, rating scale, streaming, scrobbling, and video playback. Use when working on Jellyfin integration, library browsing, playback reporting, or video casting.
Skill Claude CodeCodex
Reference for local media library: scanning, persistence, NAS responsiveness, and display-layer queries.
Skill Claude CodeCodex
The main window's built-in 76×16 (Winamp coordinates) visualization area — twelve display modes, mode switching, persistence, per-mode settings, and embedded renderer lifecycles. Use when modifying the in-skin visualizer area or its menu.
Skill Claude CodeCodex
The Met Museum Open Access slideshow engine — controls, persistence keys, throttled API client, disk image cache, empty-department handling, audio reactivity hooks. Use when modifying the Met Museum engine, its menu, the API client, or the image cache.
Skill Claude CodeCodex
Cross-cutting Metal pitfalls in NullPlayer's visualization code — command encoder ordering, render-to-texture y-flip, shader availability checks, and the AudioEngine spectrum coalescing pattern that fixes Classic/Spectrum bar stuttering. Use when writing Metal pipelines or chasing visualizer jitter/crash bugs.
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Modern skin engine, skin.json schema, element catalog, and custom skin creation. Use when creating or modifying modern skins, working on ModernSkin components, or adding UI elements to the modern system.
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Non-Retina display artifact fixes, blue line issues, tile seam corrections, and targeted redraw optimizations. Use when debugging rendering issues on 1x displays or working on skin rendering code.
Skill Claude CodeCodex
The PeppyMeter analog VU meter window — a skinnable needle/bar meter (port of project-owner/PeppyMeter) in classic + modern UI. Covers the meters.txt geometry, the CoreGraphics compositor (needle rotation + linear masks), the stereo-tap level model, meter selection/random, bundled GPL assets, and WindowManager…
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Plex API endpoints, authentication, filtering, music radio, and video content. Use when working on Plex integration, library browsing, track queries, radio features, or video playback.
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ProjectM/MilkDrop preset engine inside the visualization window — preset loading, controls, modes, audio sensitivity, beat sensitivity, drag-suspend behavior. Use when editing the ProjectM wrapper, preset folder logic, or its menu.
Skill Claude CodeCodex
Internet radio (Shoutcast/Icecast), metadata fallback, auto-reconnect, ratings/folder organization, and casting. Also covers Library Browser radio mode for Subsonic, Jellyfin, Emby, Plex, and local library (smart playlist generation, history filtering, history pages). Use when working on radio station playback…
Skill Claude CodeCodex
Sonos UPnP discovery, multi-room casting, coordinator transfer, custom checkbox UI, and protocol quirks. Use when working on Sonos casting, UPnP control, multi-room audio, or group management.
Skill Claude CodeCodex
The dedicated Metal-based spectrum analyzer window — 84-bar mode list, window geometry, docking behavior, the cropped analyzer curve used by Classic/Enhanced/Ultra, visclassic exact mode and its waveform demand. Use when modifying the spectrum window chrome, mode list, controls, or analyzer curve.