NetSynth is built in four phases ordered by technical risk. Phase 1 validates the hardest foundation: live packet capture and protocol classification without any audio code. Phase 2 builds the synthesis and encoding engine in isolation against synthetic inputs, resolving audio-specific pitfalls before integration. Phase 3 wires the two pipelines together with coordinated Ctrl+C shutdown and auto-clustering, delivering the complete v1 MVP. Phase 4 adds power-user features (BPF filter, offline pcap input) that extend the core without blocking it.
## Phases
**Phase Numbering:**
- Integer phases (1, 2, 3): Planned milestone work
- Decimal phases (2.1, 2.2): Urgent insertions (marked with INSERTED)
Decimal phases appear between their surrounding integers in numeric order.
- [ ]**Phase 1: Capture and Classification** - Live packet capture, protocol identification, and CLI scaffolding — no audio yet
- [ ]**Phase 2: Audio Synthesis Engine** - Oscillators, EMA amplitude smoothing, mixing, and MP3 encoding against synthetic inputs
- [ ]**Phase 3: Pipeline Integration and MVP** - Wire capture into synthesis, Ctrl+C with valid MP3 output, auto-clustering of unknown traffic
- [ ]**Phase 4: Power User Features** - BPF capture filter, offline pcap file input
## Phase Details
### Phase 1: Capture and Classification
**Goal**: Users can run the CLI against a live interface and see a live protocol classification summary — the full capture-to-classify pipeline validated without audio
**Goal**: The synthesis and encoding stack produces a valid MP3 from synthetic WindowSnapshot inputs — audio pipeline fully validated before any real traffic flows through it
1. Given synthetic traffic snapshots, the tool produces an MP3 file that passes `ffprobe` validation
2. Each traffic class (ICMP, DNS, TCP/443, TCP/other, UDP, SSH) produces a perceptually distinct drone tone
3. Drone layer amplitude rises and falls with traffic volume over time — sustained traffic sounds louder, quiet periods fade
4. User can specify output path via `-o` flag; it defaults to `netsynth-<timestamp>.mp3` when omitted
5. An empty (zero-packet) input produces a clear error message instead of a corrupt or zero-byte MP3
**Plans**: TBD
**UI hint**: no
### Phase 3: Pipeline Integration and MVP
**Goal**: Live capture flows end-to-end into audio synthesis — the complete v1 MVP: run, capture, Ctrl+C, get an MP3
**Depends on**: Phase 2
**Requirements**: CAPT-03, CLAS-02
**Success Criteria** (what must be TRUE):
1. User runs `netsynth -i eth0 -o out.mp3`, generates traffic, presses Ctrl+C, and receives a valid playable MP3 at `out.mp3`
2. Unrecognized traffic patterns are automatically assigned distinct drone tones — unknown traffic is not silent or merged into a single undifferentiated layer
3. The MP3 audio reflects the actual traffic mix — a session with mostly DNS sounds different from one with mostly HTTPS
**Plans**: TBD
### Phase 4: Power User Features
**Goal**: Users can scope capture with BPF expressions and sonify historical pcap files
**Depends on**: Phase 3
**Requirements**: CAPT-05, CAPT-06
**Success Criteria** (what must be TRUE):
1. User can run `netsynth -i eth0 --filter "port 53"` and only DNS traffic is captured and sonified
2. User can run `netsynth --read capture.pcap -o out.mp3` against an existing pcap file and receive a valid MP3
3. An invalid BPF filter expression produces a clear error message before any capture begins