Siavash Sameni 54cbebd34e feat(codec): Phase 1 — enable DRED on all Opus profiles, disable inband FEC
Phase 1 of the DRED integration (docs/PRD-dred-integration.md). The Opus
encoder now emits DRED (Deep REDundancy) bytes in every packet, carrying
a neural-coded history of recent audio that the decoder can use to
reconstruct loss bursts up to the configured window. Opus inband FEC
(LBRR) is disabled because DRED does the same job better and running both
wastes bitrate on overlapping protection.

Tiered DRED duration policy per PRD:
  Studio  (Opus 32k/48k/64k): 10 frames = 100 ms
  Normal  (Opus 16k/24k):     20 frames = 200 ms
  Degraded (Opus 6k):         50 frames = 500 ms

Each profile switch (via adaptive quality) updates the DRED duration to
match the new tier. A 5% packet_loss floor is applied whenever DRED is
active, because libopus 1.5 gates DRED emission on non-zero packet_loss.
Real loss measurements from the quality adapter override upward.

Escape hatch: AUDIO_USE_LEGACY_FEC=1 reverts the encoder to Phase 0
behavior (inband FEC Mode1, DRED off, no loss floor). Read once at
OpusEncoder::new; call-scoped, not re-read mid-call. Trait-level
set_inband_fec becomes a no-op in DRED mode to preserve the invariant
even if external callers forget.

Observations from the bitrate probe test (dred_mode_roundtrip_voice_pattern):
  DRED mode:   3649 bytes/sec (~29.2 kbps) on Opus 24k + 300 Hz sine
  Legacy mode: 2383 bytes/sec (~19.1 kbps)
  Delta:       +10.1 kbps

The delta is considerably larger than the "+1 kbps flat" figure I carried
into the PRD from hazy memory of published DRED benchmarks. Likely because
the input (300 Hz sine) is very compressible so the base Opus rate in
legacy mode is well below the 24 kbps target, making the delta look
disproportionate. Signal-dependent — real speech would probably show a
different ratio. If production telemetry shows the overhead is excessive,
we can cut DRED duration on the normal tier from 200 ms to 100 ms as a
first tuning lever. Not blocking Phase 1 since the test still passes
within the reasonable 2000–8000 bytes/sec bounds.

Test changes (+8 tests, total wzp-codec: 61 passing):
- dred_duration_for_studio_tiers_is_100ms  (per-profile policy)
- dred_duration_for_normal_tiers_is_200ms
- dred_duration_for_degraded_tier_is_500ms
- dred_duration_for_codec2_is_zero
- default_mode_is_dred_not_legacy  (sanity check on fresh construction)
- dred_mode_roundtrip_voice_pattern  (observes DRED bitrate, asserts bounds)
- profile_switch_refreshes_dred_duration  (verifies set_profile updates DRED)
- set_inband_fec_noop_in_dred_mode  (trait-level inband FEC no-op)

Verification:
- cargo check --workspace: zero errors, no new warnings
- cargo test -p wzp-codec: 61/61 passing (53 pre-Phase-1 baseline + 8 new)
- Empirical DRED bitrate observed via `rtk proxy cargo test
  dred_mode_roundtrip_voice_pattern -- --nocapture`

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-10 20:02:35 +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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