Siavash Sameni b830f29e66 feat(codec): Phase 3a — DRED FFI primitives (DredDecoderHandle + DredState)
Phase 3a of the DRED integration — the foundation for codec-layer loss
recovery. Adds three new safe wrappers to crates/wzp-codec/src/dred_ffi.rs
over the raw opusic-sys FFI, plus the reconstruction method on the existing
DecoderHandle. No call-site integration yet — that lands in Phase 3b (desktop)
and Phase 3c (Android).

New types:
- `DredDecoderHandle`: owns *mut OpusDREDDecoder from opus_dred_decoder_create.
  Used for parsing DRED side-channel data out of arriving Opus packets.
  This is a SEPARATE libopus object from OpusDecoder — it has its own
  internal state. Freed via opus_dred_decoder_destroy on Drop.
- `DredState`: owns *mut OpusDRED from opus_dred_alloc (a fixed ~10.6 KB
  buffer per libopus 1.5). Holds parsed DRED data between the parse and
  reconstruct steps. Reusable — parse_into overwrites contents. Tracks
  samples_available as a cached u32 so callers don't thread the value
  separately. Freed via opus_dred_free on Drop.

New methods:
- `DredDecoderHandle::parse_into(&mut self, state: &mut DredState, packet)`
  wraps opus_dred_parse with max_dred_samples=48000 (1s max), sampling_rate
  =48000, defer_processing=0. Returns the positive sample offset of the
  first decodable DRED sample, 0 if no DRED is present, or an error.
  Populates state.samples_available so subsequent reconstruct calls know
  the valid offset range.
- `DecoderHandle::reconstruct_from_dred(&mut self, state, offset_samples,
  output)` wraps opus_decoder_dred_decode. Reconstructs audio at a specific
  sample position (positive, measured backward from the DRED anchor packet)
  into a caller-provided output buffer. Validates that 0 < offset_samples
  <= state.samples_available() before calling the FFI to catch range bugs.

Tests (+7, wzp-codec total: 68 passing):
- dred_decoder_handle_creates_and_drops
- dred_state_creates_and_drops
- dred_state_reset_zeroes_counter
- dred_parse_and_reconstruct_roundtrip — end-to-end validation. Encodes
  60 frames of a 300 Hz sine wave through a DRED-enabled Opus 24k encoder,
  parses DRED state out of each arriving packet, asserts that at least one
  packet carries non-zero samples_available (DRED warm-up completes within
  the first second), then reconstructs 20 ms of audio from inside the
  window and asserts non-zero total energy. This is the hard signal that
  the full libopus 1.5 DRED FFI chain is correctly wired on our side.
- reconstruct_with_out_of_range_offset_errors — offset > samples_available
  is rejected at the Rust layer before the FFI call.
- reconstruct_with_zero_offset_errors — offset <= 0 rejected.
- dred_parse_empty_packet_returns_zero — graceful handling of empty input.

Architectural note (divergence from PRD's literal wording):
The PRD said "jitter buffer takes a Box<dyn DredReconstructor>". After
checking Cargo.toml for wzp-transport, it does NOT depend on wzp-codec —
only wzp-proto. Adding a DRED state ring inside the jitter buffer would
require a new cross-crate dependency and couple the codec-agnostic jitter
buffer to libopus internals. Instead, Phase 3b will put the DRED state
ring and reconstruction dispatch in CallDecoder (one layer up from the
jitter buffer), intercepting the existing PlayoutResult::Missing signal
and attempting reconstruction before falling through to classical PLC.
The jitter buffer itself stays unchanged. Same lookahead/backfill
semantics, cleaner layering. PRD's intent preserved, implementation
refined.

Verification:
- cargo check --workspace: zero errors
- cargo test -p wzp-codec --lib: 68 passing (61 Phase 2 baseline + 7 new)
- The roundtrip test is the acceptance gate — it proves that
  opus_dred_decoder_create, opus_dred_alloc, opus_dred_parse, and
  opus_decoder_dred_decode all work correctly through our wrappers on
  real libopus 1.5.2 output.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-10 17:51:15 +04:00

WarzonePhone

Custom lossy VoIP protocol built in Rust. E2E encrypted, FEC-protected, adaptive quality, designed for hostile network conditions.

Quick Start

# Build
cargo build --release

# Run relay
./target/release/wzp-relay --listen 0.0.0.0:4433

# Send a test tone
./target/release/wzp-client --send-tone 5 relay-addr:4433

# Web bridge (browser calls)
./target/release/wzp-web --port 8080 --relay 127.0.0.1:4433 --tls
# Open https://localhost:8080/room-name in two browser tabs

Architecture

See docs/ARCHITECTURE.md for the full system architecture with Mermaid diagrams covering:

  • System overview and data flow
  • Crate dependency graph (8 crates)
  • Wire formats (MediaHeader, MiniHeader, TrunkFrame, SignalMessage)
  • Cryptographic handshake (X25519 + Ed25519 + ChaCha20-Poly1305)
  • Identity model (BIP39 seed, featherChat compatible)
  • Quality profiles (GOOD/DEGRADED/CATASTROPHIC)
  • FEC protection (RaptorQ with interleaving)
  • Adaptive jitter buffer (NetEq-inspired)
  • Telemetry stack (Prometheus + Grafana)
  • Deployment topology

Features

  • 3 quality tiers: Opus 24k (28.8 kbps) / Opus 6k (9 kbps) / Codec2 1200 (2.4 kbps)
  • RaptorQ FEC: Recovers from 20-100% packet loss depending on tier
  • E2E encryption: ChaCha20-Poly1305 with X25519 key exchange
  • Adaptive jitter buffer: EMA-based playout delay tracking
  • Silence suppression: VAD + comfort noise (~50% bandwidth savings)
  • ML noise removal: RNNoise (nnnoiseless pure Rust port)
  • Mini-frames: 67% header compression for steady-state packets
  • Trunking: Multiplex sessions into batched datagrams
  • featherChat integration: Shared BIP39 identity, token auth, call signaling
  • Prometheus metrics: Relay, web bridge, inter-relay probes
  • Grafana dashboard: Pre-built JSON with 18 panels

Documentation

Document Description
ARCHITECTURE.md Full system architecture with diagrams
TELEMETRY.md Prometheus metrics specification
INTEGRATION_TASKS.md featherChat integration tracker
WZP-FC-SHARED-CRATES.md Shared crate strategy
grafana-dashboard.json Importable Grafana dashboard

Binaries

Binary Description
wzp-relay Relay daemon (SFU room mode, forward mode, probes)
wzp-client CLI client (send-tone, record, live mic, echo-test, drift-test, sweep)
wzp-web Browser bridge (HTTPS + WebSocket + AudioWorklet)
wzp-bench Component benchmarks

Linux Build

./scripts/build-linux.sh --prepare   # Create Hetzner VM + install deps
./scripts/build-linux.sh --build     # Build release binaries
./scripts/build-linux.sh --transfer  # Download to target/linux-x86_64/
./scripts/build-linux.sh --destroy   # Delete VM

Tests

cargo test --workspace   # 272 tests

License

MIT OR Apache-2.0

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