---
license: cc-by-4.0
task_categories:
- video-classification
- question-answering
- visual-question-answering
language:
- en
tags:
- video
- multi-video
- cross-video-reasoning
- multimodal
- benchmark
size_categories:
- 10K<n<100K
configs:
- config_name: default
  data_files:
  - split: test
    path: test/metadata.jsonl
- config_name: training
  data_files:
  - split: train
    path: train/sft_all8_answer_only.json
---

# SYNCR

SYNCR is a simulator-grounded framework for **cross-video reasoning**: questions that cannot be answered
from any single video, but require aligning events, matching identities, comparing motion, or integrating
partial observations across several videos.

Because the videos are produced in simulation, every answer is derived from environment state rather than
from human annotation. The same generators produce both an evaluation benchmark and a training set over
**disjoint** videos, so supervision can be studied without contaminating evaluation.

## Contents

| Path | Items | Description |
|---|---|---|
| `test/metadata.jsonl` | **4,000** | Evaluation benchmark, 500 questions for each of 8 tasks |
| `train/sft_all8_answer_only.json` | **15,960** | Training set, chat-formatted, answer-only targets |
| `habitat_data.tar` | — | Habitat clips used by both splits |
| `kubric_data.tar` | — | Kubric clips used by both splits |

The evaluation set draws on **4,827** distinct video files and the training set on **14,956**, with **no
video shared between the two splits**. (These are unions over tasks; per-task counts sum to more, because
some videos are used by more than one task.)

### Loading

The benchmark and the training set have different schemas, so they are published as two configs:

```python
from datasets import load_dataset

test  = load_dataset("CrossVideoReasoning/SYNCR", split="test")               # 4,000 questions
train = load_dataset("CrossVideoReasoning/SYNCR", "training", split="train")  # 15,960 examples
```

## Getting the videos

Video paths in the annotations are relative to the repository root and resolve under `videos/`:

```
videos/clvr/video_validation/video_11194.mp4
videos/clvr/video_train/video_05825.mp4
videos/habitat_data/route_plan/...
videos/kubric_data/scene_144/cam2.mp4
```

**1. Habitat and Kubric** — extract the archives in this repository:

```bash
mkdir -p videos && for f in *_data.tar; do tar -xf "$f" -C videos/; done
```

**2. CLEVRER** — these clips are **not redistributed here**. Download them from the official CLEVRER
release at **http://clevrer.csail.mit.edu** and place them so the paths above resolve:

```bash
mkdir -p videos/clvr
unzip video_validation.zip -d videos/clvr/     # 1,987 clips used by the benchmark
unzip video_train.zip      -d videos/clvr/     # 5,879 clips used by the training set
```

Which sources each split needs:

| Split | CLEVRER | Habitat | Kubric | Total distinct |
|---|---|---|---|---|
| Evaluation | 1,987 (`video_validation`) | 1,086 | 1,754 | **4,827** |
| Training | 5,879 (`video_train`) | 4,958 | 4,119 | **14,956** |

## Tasks

Eight tasks in four reasoning families, 500 evaluation questions each.

| Family | Task | Source | Videos/question | Chance |
|---|---|---|---|---|
| Temporal Alignment | Multi-Angle Synchronization | Kubric | 3 | 25% |
| Temporal Alignment | Sequential Ordering | CLEVRER | 4 | 25% |
| Spatial Tracking | Object Re-identification | Habitat | 2 | 25% |
| Spatial Tracking | Spatial Measurement | Kubric | 2 | 25% |
| Comparative Reasoning | Numerical Comparison | CLEVRER | 2 | **20%** |
| Comparative Reasoning | Kinematic Comparison | CLEVRER | 2 | 25% |
| Holistic Synthesis | Object Counting | Habitat | 3 | 25% |
| Holistic Synthesis | Route Planning | Habitat | 3 | 25% |

Numerical Comparison presents five options; every other task presents four. Correct answers are balanced
across option positions (975 each for A–D, plus 100 at E for the five-option task).

## Schema

Each row of `test/metadata.jsonl`:

| Field | Type | Description |
|---|---|---|
| `category` | string | Reasoning family (`Temporal_Alignment`, `Spatial_Tracking`, `Comparative_Reasoning`, `Holistic_Synthesis`) |
| `task` | string | Task name |
| `question` | string | The question text |
| `options` | list[string] | Answer choices, each prefixed `A)`, `B)`, … |
| `answer` | string | The correct option, verbatim |
| `videos` | list[string] | Video paths, in the order the question refers to them as Video 1, Video 2, … |
| `video_ranges` | list[[float, float]] | Start/end seconds per video, where the question is scoped to a window (1,000 questions) |
| `reasoning` | string | Simulator-derived derivation of the answer, where available (1,000 questions) |

**Video order is significant.** `videos[0]` is "Video 1" in the question text, and so on.

## Evaluation protocol

Models answer zero-shot with the videos supplied in order and labelled `Video 1:`, `Video 2:`, … We score
the parsed final option with deterministic decoding where supported.

Two notes that materially affect measured accuracy:

- **Allow enough generation budget.** Some models emit long chains of thought before the answer and, if
  truncated, produce no parseable option — which scores as wrong and understates the model. This is most
  pronounced on Synchronization. A budget of 8,192 new tokens is sufficient for the models we tested; 2,048
  is not.
- **Score unparseable answers explicitly.** Report them separately rather than silently counting them as
  incorrect, particularly for base models.

## Training set

`train/sft_all8_answer_only.json` is a chat-formatted mixture over all eight tasks (15,960 examples), with
targets containing only the answer line. Each message list interleaves `text` and `video` content blocks;
the `video` field carries the same relative paths as the benchmark.

## Video sources and licensing

Videos are rendered from three simulators, each with its own upstream terms:

- **CLEVRER** — Yi et al., ICLR 2020 — http://clevrer.csail.mit.edu
- **Kubric** — Greff et al., CVPR 2022
- **Habitat** — Savva et al., ICCV 2019 / Szot et al., NeurIPS 2021

The annotations in this repository are released under CC BY 4.0. CLEVRER clips are not redistributed here
and remain under their original terms. Rendered Habitat and Kubric clips remain subject to the licenses of
those simulators and their scene assets; consult those before redistribution.

## Changes from the previous release

This release supersedes the earlier version of this dataset and is **not** a drop-in replacement:

- The evaluation set is now **4,000 questions** (500 per task), replacing the previous 8,163-example
  single split, and a **15,960-example training split** has been added.
- Tasks were renamed and regenerated: *CLEVRER collision comparison* → **Numerical Comparison**,
  *Kubric spatial tracking* → **Spatial Measurement**, *Habitat agent/object tracking* →
  **Object Re-identification**.
- Video paths are now repository-relative rather than absolute.

Results reported in the accompanying paper correspond to **this** version.