# Feature: Processed Audio Sources

**Branch:** `feature/processed-audio-sources`
**Base branch:** `master`
**Created:** 2026-03-31
**Status:** 🟡 In Progress
**Strategy:** Big Bang
**Mode:** Automated
**Execution:** Orchestrator

## Summary

Replace hardcoded `MonoAudioSource` and `BandExtractAudioSource` types with a composable
**ProcessedAudioSource + AudioProcessingTemplate + AudioFilter** system — mirroring the
existing processed picture source pattern. Rename `MultichannelAudioSource` to
`CaptureAudioSource`. Adds 11 audio filters: channel extract, band extract, peak hold,
gain, noise gate, envelope follower, spectral smoothing, compressor, inverter, beat gate,
and delay.

Clean-slate approach: no data migration for old source types.

## Build & Test Commands
- **Build (Python):** `cd server && ruff check src/ tests/ --fix`
- **Build (TypeScript):** `cd server && npx tsc --noEmit && npm run build`
- **Test:** `cd server && py -3.13 -m pytest tests/ --no-cov -q`

## Phases

- [ ] Phase 1: Audio Filter Framework [domain: backend] → [subplan](./phase-1-audio-filter-framework.md)
- [ ] Phase 2: Audio Filters [domain: backend] → [subplan](./phase-2-audio-filters.md)
- [ ] Phase 3: Processed Audio Source Model [domain: backend] → [subplan](./phase-3-processed-audio-source-model.md)
- [ ] Phase 4: Runtime Integration [domain: backend] → [subplan](./phase-4-runtime-integration.md)
- [ ] Phase 5: Frontend — Audio Processing Templates [domain: frontend] → [subplan](./phase-5-frontend-templates.md)
- [ ] Phase 6: Frontend — Source Types [domain: frontend] → [subplan](./phase-6-frontend-source-types.md)
- [ ] Phase 7: Testing & Polish [domain: backend] → [subplan](./phase-7-testing-polish.md)
- [ ] Phase 8: Frontend Design Consistency Review [domain: frontend] → [subplan](./phase-8-frontend-design-review.md)

## Phase Progress Log

| Phase | Domain | Status | Review | Build | Committed |
|-------|--------|--------|--------|-------|-----------|
| Phase 1: Audio Filter Framework | backend | 🔨 In Progress | ⬜ | ⬜ | ⬜ |
| Phase 2: Audio Filters | backend | 🔨 In Progress | ⬜ | ⬜ | ⬜ |
| Phase 3: Processed Audio Source Model | backend | ✅ Done | ⬜ | ⬜ | ⬜ |
| Phase 4: Runtime Integration | backend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
| Phase 5: Frontend — Audio Processing Templates | frontend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
| Phase 6: Frontend — Source Types | frontend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
| Phase 7: Testing & Polish | backend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
| Phase 8: Frontend Design Review | frontend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |

## Final Review
- [ ] Comprehensive code review
- [ ] Full build passes
- [ ] Full test suite passes
- [ ] Merged to `master`