# Researchers introduce FD-VAD for streaming full-duplex speech endpoint detection

Digest AI · Research · published 2026-09-30T04:00:00Z

Canonical: https://digestai.news/story/researchers-introduce-fd-vad-for-streaming-full-duplex-speech-endpoint

## Summary

A new arXiv paper presents FD-VAD, an ASR-free system for semantic endpoint detection in streaming full-duplex voice interaction. The model determines whether a pause signals hesitation or a completed turn by mapping causal audio windows directly to Continue/Stop decisions, without relying on automatic speech recognition or dialogue state tracking.

FD-VAD combines a frozen speech encoder, a lightweight modality adapter, and a parameter-efficiently adapted language model trained with a last-chunk objective for streaming inference. It adds confidence-gated endpoint commitment to balance interruption risk against delay, and boundary-focused hard-negative sampling to improve decisions at ambiguous turn boundaries. On the TurnBench dev set, FD-VAD achieves an EOT recall of 0.853 at a false positive rate ≤0.10 in a zero-shot setting, outperforming strong streaming and non-streaming semantic turn classifiers across in-domain and conversational evaluations.

## Key points

- FD-VAD performs semantic endpoint detection directly from streaming audio without ASR
- Achieves 0.853 EOT recall at FP≤0.10 on TurnBench dev set in zero-shot setting
- Uses frozen speech encoder, modality adapter, and adapted language model with last-chunk training

## Why it matters

Enables natural turn-taking in full-duplex voice AI by detecting conversational intent from audio alone, removing ASR dependency and reducing latency.

## Sources

1. [FD-VAD: Semantic Endpoint Detection for Streaming Full-Duplex Speech](https://arxiv.org/abs/2609.35791) (arXiv cs.CL, 2026-09-30, primary source)

## Cite

Digest AI, "Researchers introduce FD-VAD for streaming full-duplex speech endpoint detection", 30 September 2026, https://digestai.news/story/researchers-introduce-fd-vad-for-streaming-full-duplex-speech-endpoint

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