tangzheng202202/dsh-voice-live

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Real-time voice interaction for DSH: press the composer mic, speak, and the assistant replies aloud. The package ships two halves:

• Host half registers the /voice WebSocket upgrade route inside the DSH host process. One connection carries a session that feeds microphone PCM to Volcengine streaming ASR (bigmodel_async with server-side VAD endpointing) and streams assistant reply text to Volcengine streaming TTS (seed-tts-2.0). The upgrade is gated by a loopback-Host + same-origin trust fence; every async operation has one lifecycle owner, audio flows through a bounded queue, and TTS is a single serial worker.
• Client half renders the composer mic control (conversation.input.left) and the Voice settings section (settings.section). A per-session VoiceController state machine owns all resources — AudioCapture (MediaStream/AudioContext/AudioWorklet), VoiceTransport (WebSocket) and PlaybackQueue (audio) — and rejects stale/late messages by generation.

The API key is read from process.env.VOLCENGINE_API_KEY on the host; the browser never holds or transmits a key.

Interaction model

• Tap the mic to start. While active the button renders a tech orb with pulse rings; speech is recognized incrementally into the composer draft.
• Endpointing is server-side: after ~1.5 s of silence a definite ASR final is emitted and submitted without pressing stop. stop() is still "send end and await the final"; cancel() discards.
• After submission the connection stays open in reply mode: the assistant's streaming text is synthesized sentence by sentence and played only after its tts_done completion event. When reply-first is enabled (default), the voice replies "好的，我去查一下。" immediately, then queues the real answer.
• Speaking again mid-reply interrupts: playback stops, TTS is cancelled, the in-flight agent turn is cancelled through DSH's agents service, old message ids are invalidated, and a new recognition starts.
• A dropped connection while listening auto-reconnects (single reconnecter, exponential backoff, max 5 attempts).

Settings

The Voice section lets you pick a voice (30 verified Volcengine voices), preview it, and toggle reply-first. The preview connects over the same /voice route and is completion-event driven (no fixed sleep).

Protocol (browser ↔ host, one WebSocket)

• browser → host: binary = 16 kHz Int16 mono mic PCM; control frames config (provider/voice/dshSessionId), asr_start, asr_end, asr_cancel, tts_push, tts_flush, tts_cancel.
• host → browser: ready, asr_partial/asr_final (with voiceSessionId, utteranceId, sequence), tts_start + binary audio + tts_done, tts_error, tts_idle, error.
• Control frames carrying a voiceSessionId must match the session; oversized frames and malformed JSON are dropped; a forged Host gets a 403.

Model Experience

Voice path

What the model sees

Nothing: the microphone stream goes to Volcengine ASR and the assistant reply text to Volcengine TTS over the host /voice route, and neither request composes, appends, or rewrites any LLM prompt (the assistant turn is DSH's ordinary agent loop).

Token effect

None: this package assembles and sends no model request, so it meters no tokens; any metering belongs entirely to the agent loop that services the submitted prompt.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

• Wake word ships as a Web Speech API implementation (Chrome/Safari, zh-CN, keyword match on the recognized transcript). It is off by default (keeps the mic held). Two constraints are documented rather than papered over:
  • Chrome's Web Speech recognition routes through Google's cloud recognizer, which is unreachable from mainland networks — the settings probe (检测唤醒可用性) surfaces the exact onerror reason (e.g. network) instead of failing silently; Safari (Apple's service) is the working browser on macOS.
  • The preferred local offline engine, sherpa-onnx WASM keyword spotting, is blocked upstream: the sherpa-onnx-wasm npm package is deleted (404 on npm/jsdelivr/unpkg/npmmirror) and the current GitHub release assets are task-specific builds whose wasm binaries contain no KWS kernel (verified: no sherpa_onnx_*_kws symbols). vosk-browser was evaluated as a fallback but its fixed Chinese model vocabulary cannot constrain custom keywords such as the default wake phrase. The WakeWordDetector interface keeps the seam for a future local WASM engine once a distribution exists.
• Echo cancellation relies on the browser's AEC (Chrome AEC3) applied to the WebRTC mic track. VoiceController.getMicAec() reports whether the browser actually applied AEC. new Audio() playback is not covered by Chrome's AEC (Chromium bug 687574), so the loop stays half-duplex: mic frames are gated while TTS plays, and barge-in stops playback before new recognition. The controlled echo test (speaker vs headphone, AEC on/off) is documented in the deliverable notes; the runtime decision is half-duplex + interrupt.
• Live captions surface as the incremental composer draft (asr_partial); there is no floating caption overlay yet.
• Server-side endpointing depends on Volcengine's optimized bidirectional endpoint (bigmodel_async + enable_nonstream); a plain bigmodel stream only returns partials and never finalizes on its own.
• The package's *.host.spec.ts tests are excluded from the repository host aggregate's typecheck (TS6307 tripped by the aggregate excluding packages/client/*/src/**); they run under vitest and the host half builds through the package tsc -b.

Standalone package status

This repository is the plugin source extracted from the DSH monorepo (packages/client/ui-voice-live). It ships 137 tests with 100% per-file coverage and is registered for DSH web via cordis.patch.yml in the monorepo bundle.

npm / dshmarket status — blocked upstream (honest note): publishing dsh-voice-live as an installable npm package is currently blocked by an incomplete official package chain: @deepseek-ai/dsh-client-runtime@0.0.1-rc.1 hard-depends on @deepseek-ai/dsh-compact, which is not published to npm (registry 404), so no plugin that depends on the DSH client runtime can be installed standalone today. Community plugins avoid this by shipping zero DSH dependencies. Options once the official chain is fixed: swap workspace:* deps for the published versions and npm publish.

Until then, build and run inside the DSH monorepo (the fork at github.com/tangzheng202202/deepseek-harness), or vendor the missing packages yourself.