VTCBench

Overview

VTCBench (Vision-Text Compression Benchmark) evaluates long-context understanding when text is represented as rendered images, and compares it with a pure-text baseline.

Task Description

• Task Type: Long-context question answering with image-based and text-based evaluation modes

• Input: Rendered context images plus a question (VTC mode), or the source text plus a question (Text mode)

• Output: Short free-form answer

• Domain: Retrieval, associative reasoning, and long-term dialogue memory

Key Features

• Provides matched VTC and Text modes for measuring the effect of vision-text compression

• Includes Retrieval, Reasoning, and Memory subsets derived from RULER, NoLiMa, and LoCoMo

• Uses pre-rendered multi-image documents to preserve the benchmark’s visual layouts

• Supports contexts spanning multiple document images

Evaluation Notes

• Default configuration uses 0-shot evaluation in VTC mode

• Use --dataset-args '{"vtcbench": {"extra_params":{"eval_mode":"text"}}}' to enable the Text baseline

• Retrieval and Reasoning use the official fractional contains_all score

• Memory uses the official maximum ROUGE-L F1 across reference answers

• The unified score metric dispatches to the official metric for each subset; its report macro_score is the unweighted mean across the three tasks

• Text mode strips HTML tags and normalizes whitespace in the same way as the official static evaluator

• Content inside <think>...</think> is excluded before scoring, matching the official evaluator

• Long-context requests may require a larger model timeout

• If dataset casting reports an offset overflow, set DATASET_TF_BATCH_SIZE=1

• Paper | Code

Properties

Property	Value
Benchmark Name	vtcbench
Dataset ID	MLLM-CL/VTCBench
Paper	Paper
Tags	LongContext, MultiModal, QA, Reasoning, Retrieval
Metrics	score, contains_all, rouge_l
Default Shots	0-shot
Evaluation Split	test

Data Statistics

Metric	Value
Total Samples	2,200
Prompt Length (Mean)	236.71 chars
Prompt Length (Min/Max)	89 / 384 chars

Per-Subset Statistics:

Subset	Samples	Prompt Mean	Prompt Min	Prompt Max
Retrieval	800	110.38	89	141
Reasoning	800	368.69	363	384
Memory	600	229.15	186	283

Image Statistics:

Metric	Value
Total Images	26,554
Images per Sample	min: 1, max: 62, mean: 12.07
Resolution Range	896x896 - 896x896
Formats	jpeg

Sample Example

Subset: Retrieval

{
  "input": [
    {
      "id": "c51f44e8",
      "content": [
        {
          "image": "[BASE64_IMAGE: jpeg, ~367.1KB]"
        },
        {
          "image": "[BASE64_IMAGE: jpeg, ~366.1KB]"
        },
        {
          "image": "[BASE64_IMAGE: jpeg, ~385.2KB]"
        },
        {
          "image": "[BASE64_IMAGE: jpeg, ~377.7KB]"
        },
        {
          "image": "[BASE64_IMAGE: jpeg, ~333.5KB]"
        },
        {
          "text": "\n\nQuestion:What are all the special magic numbers for foolish-rawhide mentioned in the provided text?"
        }
      ]
    }
  ],
  "target": "4075987, 5943250",
  "id": 0,
  "group_id": 0,
  "metadata": {
    "problem": "What are all the special magic numbers for foolish-rawhide mentioned in the provided text?",
    "answers": [
      "4075987",
      "5943250"
    ],
    "subset": "Retrieval",
    "eval_mode": "vtc"
  }
}

Prompt Template

No prompt template defined.

Extra Parameters

Parameter	Type	Default	Description
eval_mode	str	vtc	Evaluation mode: vtc (images+problem) or text (text+problem). Choices: [‘vtc’, ‘text’]

Usage

Using CLI

evalscope eval \
    --model YOUR_MODEL \
    --api-url OPENAI_API_COMPAT_URL \
    --api-key EMPTY_TOKEN \
    --datasets vtcbench \
    --limit 10  # Remove this line for formal evaluation

Using Python

from evalscope import run_task
from evalscope.config import TaskConfig

task_cfg = TaskConfig(
    model='YOUR_MODEL',
    api_url='OPENAI_API_COMPAT_URL',
    api_key='EMPTY_TOKEN',
    datasets=['vtcbench'],
    dataset_args={
        'vtcbench': {
            # subset_list: ['Retrieval', 'Reasoning', 'Memory']  # optional, evaluate specific subsets
            # extra_params: {}  # uses default extra parameters
        }
    },
    limit=10,  # Remove this line for formal evaluation
)

run_task(task_cfg=task_cfg)