Guard generateFrequencies against bandCount=1 division by zero, fix
inverted HRTF ITD delays for left-side sources, remove unused variable,
promote _interpolateGains to public API, and add NaN guard to widening.
- Remove stale IIR coefficient JSDoc comment
- Reset M/S channel state on EQ import to prevent stale assignments
- Enforce strictly increasing GEQ frequencies to prevent rounding duplicates
- Guard Q calculation against zero octave spacing (Infinity/NaN)
- Export EQ from stored metadata instead of live BiquadFilterNode state
- Accept .csv in legacy GEQ import file input
- Expose public reconnect() on BinauralDSP instead of calling _connectInternal
- Dispatch binaural-mode-changed on channel count change, not just mode change
- Remove no-op channelCount/channelCountMode on MediaElementAudioSourceNode
- Add void to floating promises (toggleBinaural, notifyBinauralChannelCount, _loadBinauralSettings)
- Wrap binauralDspSettings._setAll in try/catch for QuotaExceededError
- Make generateHRTF synchronous (no awaits, was misleadingly async)
Implement a complete binaural audio processing pipeline that sits before
EQ Studio in the signal chain. Supports multichannel (5.1) HRTF
binauralization for Dolby Atmos and Apple 3D Audio content, with
crossfeed and stereo widening for regular stereo content.
New modules:
- hrtf-generator.js: Procedural HRTF impulse response synthesis using
Woodworth head model (ITD, ILD, head shadow, pinna coloring)
- binaural-dsp.js: BinauralDSP engine with multichannel splitter,
per-channel ConvolverNode HRTF rendering, Bauer-style crossfeed
(low/medium/high), and M/S stereo widener
Integration:
- Audio graph: binaural block inserted before preamp/EQ, multichannel
passthrough via MediaElementSource channelCount=6
- Storage: binauralDspSettings with full persistence (JSON in localStorage)
- UI: toggle + sub-controls (crossfeed level, HRTF preset, width slider)
placed before EQ Studio in settings
- Player: auto-enables binaural DSP when Atmos content detected,
shows binaural badge on Atmos tracks
- Rename section header to EQ Studio with updated description
- Add ST/M/S channel select dropdown to each parametric band control
- Move Parametric EQ tab before AutoEQ
- Hide Original/Target/Corrected legend in parametric mode
- Add per-band M/S processing with full encoder/decoder matrix in Web Audio API
- Right-click context menu on EQ nodes for filter type and channel switching
- Right-click empty graph space to add nodes
- Remove nearest-node snap-click interaction
- Replace IIR shelf filters with native BiquadFilter for glitch-free updates
- Add 6 M/S showcase presets with research-informed mastering values
- Add 5 shelf-based stereo presets (Warm, Bright, Hi-Fi, Dark, Radio Ready)
- Standard presets now reset all bands to stereo/peaking
- Graph contrast fix for light themes using color-mix()
- Colored help button and rewritten how-to documentation
- Default graph zoom changed to ±16 dB
- Pad band arrays when import/AutoEQ has fewer filters than MIN_BANDS
- Early return in applyAutoEQBands for zero enabled bands
- Persist interpolated gains before audio rebuild on band count change
- Derive export Q from actual octave spacing between adjacent bands
- Validate inputs in all GEQ storage setters
- Add Bands/Min Hz/Max Hz controls to legacy EQ section
- Dynamic frequency generation with log spacing and auto-scaling Q
- Import/export handles variable band counts, Q optional for shelves
- Custom presets interpolate across different band counts
- Update legacy EQ tutorial for new controls
- Add Export APO button to legacy graphic EQ (GraphicEQ config line format)
- Fix shelf filters ignoring Q: use IIR filters with RBJ cookbook coefficients
- Update graph visualization to use actual Q for shelf curves
- Omit Q from shelf filters in all EQ text exports
- Preserve existing preamp when importing files without Preamp line
- Extend import regex to accept k/kHz/Hz suffixes and +signed gains
- Rename localStorage key to monochrome- prefix for backup/restore compat
- Add try/catch to localStorage writes for quota/disabled storage
- Validate custom preset gains array before applying
- Fix delete button visibility for all preset change paths
- Add overflow-x: auto for mobile EQ band scrolling
- Add flex-wrap and responsive sizing for bottom controls on mobile
