README.md

---
license: apache-2.0
library_name: rubato
pipeline_tag: voice-activity-detection
tags:
- turn-taking
- endpointing
- spoken-dialogue
- survival-analysis
- realtime
- rubato
---

# Rubato — turn-taking timing model

**Predict the silence as a distribution, then decide when to speak.**

A 3,137-parameter model that answers one question at 50 Hz: *given
everything heard so far, how much longer will this silence last?*  A dynamic
program turns that distribution into a start/wait decision under an explicit,
tunable asymmetry between talking over someone and answering late.

It decides **when** to talk. It does not decide **what** to say, and it contains
no speech recogniser, no language model and no synthesiser. It is a middle layer
you drop into an existing pipeline.

## Three lines

```python
from rubato import load_pretrained, CostWeights

taker = load_pretrained(hf_repo="NagaYu/rubato-timing", weights=CostWeights.from_seconds_per_collision(2.0))
should_speak = taker.push_audio(chunk).should_speak     # one 20 ms frame of float audio
```

`seconds_per_collision` is the whole configuration surface: *how many seconds of
extra latency is one talk-over worth to you?*  Small values give an eager agent,
large values a patient one, and the sweep between them is the Pareto front below.

Framework adapters: `rubato.integrations.pipecat_processor.RubatoTurnGate` and
`rubato.integrations.livekit_plugin.RubatoTurnDetector`.

Source, benchmark protocol, ablations and sensitivity analyses: **https://github.com/NagaYu/rubato**

## What it was measured to do

![Talk-over rate against response latency: Rubato's frontier lies inside the fixed-threshold frontier](./pareto_maptask.png)

*Both axes are minimised. A fixed threshold can only ever trace the outer curve -- one threshold buys one point. The inset is the band real systems ship in.*

Held out on **5988 silences** from speakers never seen in training (maptask, CC-BY-4.0).

| | |
|---|---|
| covers the fixed-threshold frontier | **86%** of its points |
| covers the semantic-completeness frontier | **100%** of its points |
| latency saved at matched talk-over | **84 ms** vs fixed, 96 ms vs semantic |
| talk-over removed at matched latency | **2.8 pp** vs fixed, 2.1 pp vs semantic |
| hazard calibration (ECE) | 0.0007 |
| CRPS skill over a covariate-free hazard | +0.173 |
| layer cost per 20 ms frame | **0.26 ms** median, 0.49 ms p99 |

At the operating point matched to a 1000 ms threshold: latency **1000 → 772 ms** (95 % CI 707–831), talk-over **6.3% → 6.5%** (95 % CI 5.6%–7.6%). Intervals are a conversation-level cluster bootstrap.

## How it works

1. **Discrete-time hazard.** `h_k = P(partner resumes in frame k+1 | silent
   through k, evidence up to k)`, from a one-hidden-layer network over a causal
   feature vector: a radial-basis expansion of log elapsed silence, turn-so-far
   duration and pause count, transcript completeness (gated by ASR lag, because a
   real recogniser has not delivered the last word yet), terminal prosody where
   audio exists, acoustic precursor cues such as in-breaths, and a running
   per-partner posterior.
2. **Optimal stopping.** A backward dynamic program over the forecast survival
   curve minimises `alpha * P(collision) + beta * latency`. Being pre-empted --
   the human carries on while the agent is still silent -- costs nothing, which
   is what produces the human-like behaviour: when a resumption looks likely,
   waiting is nearly free; when the floor is clearly open, the agent can start at
   zero gap.
3. **Online entrainment.** Conjugate posteriors over each partner's pause and gap
   distributions, and an EMA of their speech rate, shrinking to a population
   prior so the first thirty seconds are never worse than not adapting.

## Inputs, outputs, and what it needs from you

| you provide | per frame |
|---|---|
| 20 ms of mono audio (any rate; 16 kHz assumed) | required |
| the ASR's partial transcript | optional, improves accuracy |
| a partner id | optional, enables entrainment |

| you get back | |
|---|---|
| `should_speak` | the decision |
| `decision.planned_onset_s` | when it currently intends to start |
| `decision.p_overlap_now` | collision probability if it started this instant |
| `prediction.future_hazards` | the full predicted silence distribution |

## Limitations

- **English lexical features.** The temporal and acoustic half transfers; the
  completeness features were fitted on English and will mislead elsewhere.
  Retrain on target-language data.
- **Task-oriented training data.** Trained on the HCRC Map Task Corpus: two people collaborating on a route-following task.  Open-domain conversation has
  longer, more variable gaps; expect to retune `seconds_per_collision`.
- **Two-party only.** Multi-party floor management is a different problem.
- **The offline protocol makes an assumption.** On a floor transfer we assume the
  floor would have stayed open had the agent not spoken. The alternative is
  worse (informative censoring); both are reported in the repository README.
- **It is a timing layer, not a turn-taking oracle.** It cannot know that you
  paused because you were about to say something difficult.

## Responsible use

Better timing makes an assistant less irritating. It also makes a synthetic voice
harder to distinguish from a person, and that is a use this model is **not** for.

- **Disclose that the system is an AI.** This model is released on the assumption
  that the deployment does so, in the modality the user is actually attending to
  -- spoken, not buried in a settings page.
- **Do not use it to impersonate anyone**, to make an automated caller pass as
  human, or in any deployment whose value depends on the person not knowing.
  Several jurisdictions require disclosure for automated calls; treat that as a
  floor, not a target.
- **Do not use it to time interruptions strategically** -- to cut a person off at
  a moment calculated to stop them finishing a thought. The asymmetric cost makes
  that easy to configure, which is exactly why it is named here.
- The entrainment state is a behavioural profile of an individual. Keep it in
  session scope unless you have a reason and consent to persist it.

## Training data

**maptask** (CC-BY-4.0). Anderson et al. (1991), The HCRC Map Task Corpus. Language and Speech 34(4). Annotations (c) 2007 HCRC, Univ. of Edinburgh & Univ. of Glasgow. CC BY 4.0. https://groups.inf.ed.ac.uk/maptask/

No audio was redistributed in building this model.

## Citation

```bibtex
@software{rubato,
  title  = {Rubato: predicting silence distributions for spoken-dialogue turn-taking},
  year   = {2026},
  url    = {https://huggingface.co/NagaYu/rubato-timing}
}
```