✨ feat: Add MS (Mid-Side) Audio Processor with Multi-Effect Support #273
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Implemented a comprehensive Mid-Side audio processor that can work independently or alongside reverb/equalizer effects, enabling advanced stereo manipulation and channel routing for music practice. **MS Processor Features:** - 9 processing modes: bypass, left-only, right-only, mid-only, side-only, width adjustment, channel swap, mono, reverse-phase - 15 presets across two categories: - Channel modes: left/right/mid/side isolation, swap, mono - Stereo processing: width control, vocal focus, instrument isolation, karaoke - AudioWorklet-based processing with 5 parameters: mode, width, midGain, sideGain, balance - Smooth parameter ramping to prevent audio clicks **Multi-Effect Chain Architecture:** - Refactored AudioManager to support simultaneous effects - Dynamic effect chaining: gain → equalizer → MS processor → reverb → soundTouch → destination - Frequency-domain effects (reverb/equalizer) remain mutually exclusive - MS processor (stereo transformation) works with any frequency-domain effect - Dual-node support for effects with filter chains (equalizer with 19 BiquadFilters) - Safe cleanup with try-catch to prevent errors during disposal **Effect Lifecycle Improvements:** - Added `_activeEffects` tracking object in AudioManager - Implemented `rebuildEffectChain()` for dynamic audio graph construction - Created `removeEffect()` method for granular effect removal - Fixed source reconnection bug that caused all effects to stop working - AudioContext readiness checks before applying effects - Effect reapplication after media element recreation **UI Integration:** - New MS tab with two-section control layout - Channel modes (basic presets) and stereo processing (advanced presets) selectors - Integrated with existing AudioEffectInputs component - Added to TabsList navigation and settings store - MS processor module path registered in sessionStorage **Store Updates:** - Extended AudioEffect type with `msProcessor` field - Added MS processor presets to config store - Effect reapplication listener for media recreation events - Proper storage sync with type validation Closes requirement for advanced stereo manipulation in music practice workflow, enabling users to isolate vocals, enhance instruments, adjust stereo width, and apply karaoke effects while maintaining reverb or EQ settings. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Fix left-only and right-only modes to properly route audio to individual speakers instead of duplicating to both channels. Previously, selecting "left-only" would play the left channel in both ears - now it correctly plays only in the left speaker with silence in the right. Changes: - Mode 1 (left-only): outL = L, outR = 0 (was outR = L) - Mode 2 (right-only): outL = 0, outR = R (was outL = R) This matches standard channel routing behavior and enables proper mono-channel isolation for practice and analysis.
Add support for real-time manual adjustment of MS processor parameters, though currently unused as UI remains preset-only. This infrastructure enables future enhancement to allow fine-tuning of mode, width, gains, and balance beyond preset configurations. Components added: - MSControls.svelte: UI component with sliders for manual adjustments - ms-params.ts: Store for managing manual parameter state - applyManualParams(): Method to apply real-time parameter changes Integration: - FROM_MS_PARAMS_LISTENER message handler in media-element - updateMSParams() method in MediaOverride - Parameter store with storage sync and reapplication support Note: MSControls component exists but is not currently used in MS.svelte, which continues to use the preset-only AudioEffectInputs component.
Fix critical bug where equalizer effect caused complete audio loss by preserving internal filter chain connections during effect rebuild. The cleanup function was incorrectly disconnecting equalizer's input and output nodes, breaking the internal chain of 19 BiquadFilterNodes. Additional fixes: - Add store imports to App.svelte to ensure initialization - Add REQUEST_EFFECT_REAPPLY listeners to all effect stores - Set Web Audio API element volume to 1 and unmuted in setupAudioChain - Store MediaElement reference on source for global listener pattern - Fix effect application order to allow proper multi-effect chaining - Remove debug logging from equalizer and audio chain rebuild - Add source disconnect in cleanupEffectChain to prevent duplicates The equalizer now works correctly both independently and in combination with other effects (reverb, MS processor).
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Summary
Adds a new MS (Mid-Side) audio processor that allows independent manipulation of mid (center) and side (stereo) audio channels. This enables advanced stereo imaging effects and provides fine-grained control over the stereo field.
Key Features
Implementation Details
Audio Processing Chain:
MS Processor Architecture:
UI Components:
Presets Included
Bug Fixes
Technical Changes
New Files:
src/lib/audio-effects/ms-processor/index.ts- Main MS processor classsrc/lib/audio-effects/ms-processor/presets.ts- Preset definitionssrc/lib/components/MSControls.svelte- UI controls componentsrc/lib/components/views/MS.svelte- MS view tabsrc/lib/stores/ms-params.ts- MS parameters storesrc/public/ms-processor.js- AudioWorkletProcessor implementationModified Files:
audio-manager.tsfor multi-effect chainingmedia-element.tswith global listener patternmedia-override.tseffect application logicequalizer/index.tsinternal chain preservationApp.svelteTest Plan
Breaking Changes
None - this is a new feature addition.
Migration Notes
No migration needed. The MS processor is opt-in via the new MS tab.