---
license: other
task_categories:
- video-text-to-text
- question-answering
language:
- en
tags:
- video
- long-video
- memory
size_categories:
- n<1K
---

# VMemArena

Open-ended QA benchmark for **long-video memory**. 1000 questions over 561 videos
(680 h of footage). Every question is free-form: there are no options to choose from.

## Files

| file | contents |
|---|---|
| `vmemarena.json` | 561 video entries, each with its questions |
| `videos.jsonl` | per-video metadata (duration, fps, resolution, codec, size) |
| `videos/` | 561 `.mp4` files, named by `video_id` |

## Schema

```jsonc
// vmemarena.json — a list of video entries
{
  "video_id": "JmTtREhkJsA",
  "video_file": "videos/JmTtREhkJsA.mp4",
  "duration_s": 2139.97,
  "fps": 25.0,
  "has_audio": true,
  "questions": [
    {
      "qid": "CG-Bench:5477",
      "text": "How many people were left on the purple team when ...",
      "gt": "Four people.",
      "time_bin": "T1",              // retention span, T1 < T2 < T3 < T4
      "capability": "state_update",  // memory capability probed
      "scene_type": "multi_entity",  // visual scene character
      "source_dataset": "CG-Bench"
    }
  ]
}
```

## The three axes

**Retention span** (`time_bin`) is balanced by construction — 250 questions each.

| axis | values |
|---|---|
| `time_bin` | T1 250 · T2 250 · T3 250 · T4 250 |
| `capability` | evidence_composition 254 · attribute_recall 253 · entity_tracking 251 · temporal_spatial_relation 186 · state_update 56 |
| `scene_type` | multi_entity 380 · text_rich 275 · interaction_rich 218 · state_changing 127 |

`capability` and `scene_type` are reported rather than enforced: they reflect what the
sources contain. `state_update` is supply-limited at 56 questions — treat per-class
accuracy on it with the corresponding error bar, not as a headline number.

## Notes on video_id

`video_id` is usually the source platform's id, with two exceptions that keep ids unique:

- `<id>__<offset>` — a clip, not the full video (17 files).
- `<id>__<source>` — the same platform id was collected independently by two source
  datasets and the two files genuinely differ, e.g. `OFbyNU6UQQs__ScaleLong` has no
  audio track while `OFbyNU6UQQs__VideoOdyssey` does. They count as two videos.

## Provenance

Questions carry `source_dataset`. The 17 `StreamArena-HR` questions passed a separate
audit from the other 983; the two review pipelines were never calibrated against each
other, so filter on `source_dataset` if that matters for your analysis.

Videos belong to their original publishers and are redistributed here for internal
evaluation only.