# br41ndmg
```
br41ndmg/
├── Cargo.toml # Workspace manifest and dependencies
├── .gitignore # Ignores: /target, *.wav, flamegraphs
├── README.md # Overview, quick start, roadmap
│
├── src/
│ ├── lib.rs # Public re-exports, crate root
│ ├── sinc.rs # f64/f32 sinc helpers and kernel builders
│ ├── window.rs # f64/f32 Hann, Hamming, Blackman, Kaiser
│ ├── filter.rs # f64/f32 FIR kernel generation and normalization
│ ├── io.rs # WAV/FLAC read, WAV write, and AudioBuffer helpers
│ ├── polyphase.rs # Polyphase sinc filter-bank builder and phase lookup
│ ├── resampler.rs # Offline and streaming polyphase resamplers
│ ├── error.rs # Error enum with thiserror
│ ├── utils.rs # Shared validation helpers
│ └── bin/
│ └── br41ndmg.rs # CLI: .wav/.flac in → .wav out (`cargo install`)
│
├── tests/
│ ├── file_io.rs # WAV normalization, write, and layout tests
│ ├── filter.rs # FIR helper tests
│ ├── resampler.rs # Offline interleaved resampler tests
│ ├── streaming.rs # Chunked streaming equivalence tests
│ ├── impulse.rs # Impulse identity and symmetry checks
│ ├── sine.rs # Sine round-trip and passband RMS checks
│ ├── sweep.rs # Sweep attenuation regression checks
│ ├── quality_tests.rs # DC, alias suppression, and stereo quality checks
│ └── real_audio.rs # End-to-end tests on test_subjects/*.flac (skip if absent)
│
├── benches/
│ └── resampler_bench.rs # Criterion mono/stereo resampling benches
│
├── examples/
│ └── tone_resample.rs # Synthetic sine written as WAV output
│
└── docs/
├── USAGE.md # End-user guide and recipes
├── ARCHITECTURE.md # Module map, data flow
├── DSP_NOTES.md # Sinc math, polyphase theory
├── REALTIME.md # Callback rules, latency tradeoffs
├── TEST_PLAN.md # Signals, thresholds, and checked-in coverage
├── BENCHMARK_PLAN.md # Current coverage and next perf work
├── REQUIREMENTS.md # Scope, capabilities, non-goals
├── PERFORMANCE.md # Current performance notes
└── PROJECT_GOAL.md # Phase-by-phase build plan
```