S³T · Self-Supervised Self-Distillation over Time

Temporal Self-Distillation: Learning Visual State Tracking in Videos Without Supervision

1ELLIS Institute Finland & Department of Computer Science, Aalto University, Finland

2Mohamed bin Zayed University of Artificial Intelligence, UAE

Comparison of S3T with supervised, self-evolving, spatial privileged, and temporal self-supervised methods

A dense reading of an unlabeled clip teaches the same model to maintain scene state from a sparse reading. Training uses no labels, separate teacher, or external reward.

Qualitative results

Qualitative results on VSTAT

S³T answers all ten video examples correctly, while all five comparison models answer incorrectly. The final tab shows the long-prefix comparisons from the paper.

Source: VSTAT-YouTube

Question

How many different players hit the ball in total?

Reference answer: 10

ModelAnswer
S³T10 Correct
LLaVA-OV-2-8B8
Video-Zero-8B2
Molmo2-8B3
Qwen3-VL-8B2
InternVL3.5-8B3

Overview

Abstract

We introduce S³T, Self-Supervised Self-Distillation over Time, a self-contained framework for continuous visual state tracking in videos. A dense reading of an unlabeled clip acts as a privileged teacher for a sparse reading of the same model. The model generates its own target, so training requires no labels, separate teacher, or reward signal and adds no inference cost.

On LLaVA-OneVision-2-8B, a single S³T model improves VSTAT accuracy by 1.74 points, souping two specialists gives 2.38 points, and adapting the vision encoder gives 2.70 points. Training uses only unlabeled synthetic clips. The learned capability also transfers to real videos, improving VSTAT-YouTube cumulative-state questions by 7.95 points and MVBench Action Count by 4.50 points.

Method

Temporal self-distillation from two views of one clip

S3T architecture with sparse student, dense teacher, and frozen reference roles
  1. 01

    Sample the full clip twice

    The student reads 12 uniformly spaced frames and the teacher reads 24. Both views cover the same temporal extent.

  2. 02

    Score one generated answer

    The sparse student greedily answers a fixed state question. Student, teacher, and reference roles score that answer token by token.

  3. 03

    Update the student adapter

    The dense teacher supplies the positive target. The adapter-disabled base model anchors the update, and gradients flow only through the student LoRA.

$$\mathcal{L}=D_{\mathrm{JSD}}\!\left(\operatorname{sg}[P_T]\,\|\,P_S\right)+\beta\,D_{\mathrm{JSD}}\!\left(\operatorname{sg}[P_R]\,\|\,P_S\right)$$

An adaptive controller adjusts $\beta$ to keep the reference divergence near a fixed set point.

Training data

StateGen

300 unlabeled videos · 512 x 512 · 12 FPS · 20 seconds · 240 frames

StateGen event vocabulary and four example training clips

Each clip contains 6 to 15 near-identical entities and 7 to 11 add, remove, move, swap, or recolor events. Occlusion and camera motion continue throughout the clip. State logs and the counts shown in the figure are not used for training.

Results

Results on VSTAT

VSTAT leaderboard

Accuracy (%) on 1,500 VSTAT questions. A dagger marks scores reproduced with our evaluation protocol.

MethodAvgState elementState structure
CountLoc.Attr.Atom.Seq.SetDict
Human performance90.592.889.986.493.777.590.092.4
Open-source models
LLaVA-OV-2-8B35.128.343.040.533.538.746.927.3
LLaVA-OV-2-8B (codec)35.028.642.040.633.937.046.327.6
Molmo2-4B34.431.639.734.537.133.636.727.1
Cambrian-S-7B34.233.233.636.934.030.640.232.5
Molmo2-8B34.030.937.037.034.736.339.127.0
Qwen3VL-8B33.230.937.033.932.433.337.931.5
InternVL3.5-2B31.829.633.934.131.729.936.329.9
Cambrian-S-3B31.829.732.735.032.731.935.127.2
VITA-1.5-7B31.525.536.338.629.433.043.126.3
Qwen3VL-4B31.327.033.337.930.432.839.825.8
InternVL3.5-8B30.625.133.239.226.933.841.828.3
Qwen3VL-2B29.429.428.230.532.524.932.123.5
Cambrian-S-1.5B29.326.034.131.028.031.031.829.3
LLaVA-OV-7B28.620.134.839.424.530.043.825.0
LLaVA-OV-0.5B21.314.633.921.719.725.822.220.9
Self-evolving methods
Qwen3-VL-4B†31.4327.733.736.631.932.538.524.4
Video-Zero-4B†31.6327.734.536.532.132.337.825.5
Qwen3-VL-8B†34.1132.637.833.435.033.137.130.4
Video-Zero-8B†33.8932.037.234.334.135.538.329.1
Qwen2.5-VL-7B†31.8425.237.439.528.839.441.626.2
EvoGround†32.6626.736.640.629.739.542.927.0
Ours
LLaVA-OV-2-8B†34.7427.742.041.432.637.048.627.4
S³T (SFT teacher)34.4526.042.243.630.938.050.927.5
S³T36.4830.441.743.335.239.447.828.8
S³T (soup)37.1232.440.743.037.241.444.928.4
S³T (soup, + vision enc.)37.4432.642.342.137.742.845.527.4

Our reproduced LLaVA-OV-2-8B base scores 34.74. Reported gains use this score as the reference.

Per-axis comparison

Radar comparison of S3T and size-matched 8B open models across VSTAT axes

S³T improves the cumulative-state axes against size-matched 8B open models.

Specialists and model soup

Per-axis changes from two S3T specialists and their model soup

The two state probes give complementary specialists. Their soup improves Count, Atomic, and Sequence with no extra inference cost.

Real-video transfer

Transfer to real videos

Real-video benchmarkBaseS³T (soup)S³T (soup, + vis.)
Requires a running tally
VSTAT-YouTube, cumulative state43.41+7.35+7.95
MVBench, Action Count54.50+3.00+4.50
General video understanding
TempCompass, multiple choice74.49−1.01ns−0.06ns
TempCompass, yes/no77.62+0.24ns+0.04ns
TempCompass, caption matching85.70−1.00ns+0.20ns
MMVU55.200.000.00

Base gives the original score. S³T columns give the change in accuracy. ns marks a change that is not statistically significant.

Analysis

Teacher view and distillation objective

Student and teacher frame budgets

VSTAT gain as student and teacher frame budgets vary

The gain depends on both frame budgets. The strongest region lies near a 12-frame student and a 24-frame teacher.

Acknowledgements

Acknowledgements

We acknowledge funding from the Research Council of Finland (projects 362408 and 339730). This work was supported by the Research Council of Finland Flagship programme: Finnish Center for Artificial Intelligence FCAI. We acknowledge the computational resources provided by the Aalto Science-IT project.