Cambrian-W Benchmark - Shuffled Correct Order
Version: 2.0 (Shuffled Correct Order)
Date: 2025-02-28
Total Videos: 466 (40 long + 426 short)
Total Eval Items: 60,687
Critical Fix: Shuffled Temporal Order
Problem: In the original format, subset_concepts and correct_order had the same sequence, allowing models to answer "ABCD" based on position bias rather than true temporal understanding.
Solution: Now correct_order (temporal sequence) is randomly shuffled, while subset_concepts maintains fixed label order (A, B, C, D).
Example
Before (Flawed):
{
"subset_concepts": ["signpost", "shipping container", "fire hydrant", "tower"],
"correct_order": ["signpost", "shipping container", "fire hydrant", "tower"],
"answer": "ABCD"
}
// Model can answer "ABCD" by position bias β CORRECT (undeserved)
After (Fixed):
{
"subset_concepts": ["signpost", "shipping container", "fire hydrant", "tower"],
"correct_order": ["shipping container", "tower", "signpost", "fire hydrant"],
"answer": "BDAC"
}
// Model must understand: BβDβAβC, not just output "ABCD"
Label Mapping (Fixed):
- A = signpost
- B = shipping container
- C = fire hydrant
- D = tower
Temporal Sequence (Shuffled): shipping container β tower β signpost β fire hydrant
Answer: "BDAC" (must map temporal order to fixed labels)
Data Files
| File | Size | Videos | Eval Items | Description |
|---|---|---|---|---|
part1_long_videos_all.json |
26MB | 40 | 20,705 | Long videos, all tasks, dual format |
part2_short_place_motion.json |
37MB | 426 | 18,154 | Short videos, spatial & motion tasks |
part3_short_objects.json |
14MB | 426 | 21,828 | Short videos, object tasks, dual format |
Data Structure
Part 1: Long Videos (40 videos, 111.9 hours)
Source: new_long_video/corrected_json_2 (fully rechecked)
Tasks:
| Task | Format | Eval Items | Metric |
|---|---|---|---|
| Object Counting | Fill-in-blank | 3,799 | MRA |
| First Appearance Recall | Choice + Direct | 1,559 Γ 2 | Acc / Exact Match |
| Last Appearance Recall | Choice + Direct | 1,506 Γ 2 | Acc / Exact Match |
| Frame Recall (Baseline) | Multiple Choice | 4,770 | Accuracy |
| Frame Recall (Rotated) | Multiple Choice | 4,770 | Accuracy |
| Motion Direction | Multiple Choice | 1,236 | Accuracy |
Part 2: Short Videos - Place & Motion (426 videos)
Tasks:
| Task | Format | Eval Items | Metric |
|---|---|---|---|
| Frame Recall (Baseline) | Multiple Choice | 8,040 | Accuracy |
| Frame Recall (Rotated) | Multiple Choice | 8,040 | Accuracy |
| Motion Direction | Multiple Choice | 2,074 | Accuracy |
Part 3: Short Videos - Objects (426 videos)
β οΈ Note: Partially rechecked
Tasks:
| Task | Format | Eval Items | Metric |
|---|---|---|---|
| Object Counting | Fill-in-blank | 7,396 | MRA |
| First Appearance Recall | Choice + Direct | 3,608 Γ 2 | Acc / Exact Match |
| Last Appearance Recall | Choice + Direct | 3,608 Γ 2 | Acc / Exact Match |
Appearance Task Format Details
Direct Order Format (*_direct)
{
"task_type": "first_appearance_recall_direct",
"question_format": "direct_order",
"evaluation_metric": "exact_match",
"subset_concepts": ["signpost", "shipping container", "fire hydrant", "tower"],
"correct_order": ["shipping container", "tower", "signpost", "fire hydrant"],
"original_order": ["signpost", "shipping container", "fire hydrant", "tower"],
"shuffled": true,
"question": "[Direct-Order] Arrange by first appearance: signpost, shipping container, fire hydrant, tower",
"checkpoints": [{
"checkpoint": 10,
"answer": "BDAC",
"concepts_seen": ["shipping container", "tower", "signpost", "fire hydrant"]
}]
}
Label Mapping:
- A β signpost
- B β shipping container
- C β fire hydrant
- D β tower
Temporal Order: B β D β A β C
Prompt Template:
Arrange objects by first appearance:
Objects:
A) signpost
B) shipping container
C) fire hydrant
D) tower
Output the order as a sequence of 4 letters.
Answer with only the 4 letters in order, nothing else.
Expected Answer: "BDAC"
Why this prevents bias: Model cannot simply output "ABCD". It must understand that "shipping container" (B) appears first, then "tower" (D), etc.
Choice Format (*_choice)
{
"task_type": "first_appearance_recall_choice",
"question_format": "single_choice",
"evaluation_metric": "accuracy",
"subset_concepts": ["signpost", "shipping container", "fire hydrant", "tower"],
"question": "[Single-Choice] Arrange by first appearance: signpost, shipping container, fire hydrant, tower",
"checkpoints": [{
"options": [
"A) signpost β shipping container β fire hydrant β tower",
"B) shipping container β tower β signpost β fire hydrant",
"C) fire hydrant β signpost β tower β shipping container",
"D) tower β fire hydrant β shipping container β signpost"
],
"answer": "B"
}]
}
Correct Option: "B) shipping container β tower β signpost β fire hydrant"
Evaluation Guide
Loading Data
import json
# Load Part 1 (long videos)
with open('benchmark_shuffled/part1_long_videos_all.json') as f:
part1 = json.load(f)
# Access a video
video = part1['videos'][0]
task = video['tasks'][0] # First task
if 'first_appearance_recall_direct' in task['task_type']:
# Direct order format
concepts = task['subset_concepts'] # Fixed order
label_map = {c: chr(ord('A')+i) for i, c in enumerate(concepts)}
for cp in task['checkpoints']:
if cp.get('answer'):
correct_order = cp['correct_order'] # Shuffled temporal order
answer = cp['answer'] # Sequence like "BDAC"
# Verify
expected = ''.join([label_map[c] for c in correct_order])
assert answer == expected, "Answer mismatch!"
Direct Format Evaluation
def evaluate_direct(model, task, video_path=None):
"""Evaluate direct order format task."""
results = []
concepts = task['subset_concepts'] # Fixed order
# Build concept list for prompt
concept_list = '\n'.join([f"{chr(ord('A')+i)}) {c}" for i, c in enumerate(concepts)])
n = len(concepts)
for cp in task['checkpoints']:
if cp.get('answer') is None:
continue
# Build prompt
prompt = f"""{task['question']}
Objects:
{concept_list}
Output the order as a sequence of {n} letters.
Answer with only the {n} letters in order, nothing else."""
# Get prediction
pred = model.generate(prompt, video_path)
pred_seq = parse_sequence(pred)
# Check correctness (exact match)
is_correct = (pred_seq == cp['answer'])
results.append({
'gt': cp['answer'],
'pred': pred_seq,
'correct': is_correct
})
return results
def parse_sequence(text):
"""Parse sequence like 'BDAC' from model output."""
import re
text = text.upper()
text = text.replace('β', '').replace('->', '').replace(' ', '').replace(',', '')
match = re.search(r'[ABCD]{2,4}', text)
if match:
return match.group(0)
return ''
Choice Format Evaluation
def evaluate_choice(model, task, video_path=None):
"""Evaluate choice format task."""
results = []
for cp in task['checkpoints']:
if cp.get('answer') is None:
continue
# Build prompt
prompt = f"""{task['question']}
Options:
{chr(10).join(cp['options'])}
Answer with only the letter (A, B, C, or D)."""
# Get prediction
pred = model.generate(prompt, video_path)
pred_letter = extract_letter(pred)
# Check correctness
is_correct = (pred_letter == cp['answer'])
results.append({
'gt': cp['answer'],
'pred': pred_letter,
'correct': is_correct
})
return results
def extract_letter(text):
"""Extract A/B/C/D from model output."""
text = text.upper()
for letter in ['A', 'B', 'C', 'D']:
if letter in text:
return letter
return 'A'
Object Counting Evaluation
def evaluate_counting(model, task, video_path=None):
"""Evaluate object counting task."""
results = []
for cp in task['checkpoints']:
if cp.get('answer') is None:
continue
prompt = f"""{task['question']}
You are at checkpoint {cp['checkpoint']} of {cp['checkpoint_of']}.
Answer with only a single integer number."""
pred = model.generate(prompt, video_path)
nums = re.findall(r'\d+', pred)
pred_val = int(nums[0]) if nums else 0
gt_val = cp['answer']
# MRA metric
mra = max(0.0, 1.0 - abs(pred_val - gt_val) / max(gt_val, 1))
results.append({
'gt': gt_val,
'pred': pred_val,
'mra': mra
})
return results
Metrics Calculation
Accuracy (Choice tasks)
accuracy = sum(r['correct'] for r in results) / len(results) * 100
Exact Match (Direct tasks)
exact_match = sum(r['correct'] for r in results) / len(results) * 100
MRA (Counting tasks)
mra = sum(r['mra'] for r in results) / len(results) * 100
Dual Format Comparison
Run both formats on same checkpoints:
# Load both formats
choice_task = load_task('first_appearance_recall_choice')
direct_task = load_task('first_appearance_recall_direct')
# Evaluate
choice_results = evaluate_choice(model, choice_task, video_path)
direct_results = evaluate_direct(model, direct_task, video_path)
# Compare
choice_acc = sum(r['correct'] for r in choice_results) / len(choice_results)
direct_acc = sum(r['correct'] for r in direct_results) / len(direct_results)
print(f"Choice: {choice_acc:.2%}")
print(f"Direct: {direct_acc:.2%}")
print(f"Gap: {choice_acc - direct_acc:.2%}")
Expected Gap:
- First Appearance: ~40% (60% β 20%)
- Last Appearance: ~44% (55% β 11%)
Large gap β model relies on bias/heuristics
Small gap β model truly understands temporal order
Data Quality
| Part | Quality | Recommendation |
|---|---|---|
| Part 1 | β Fully rechecked | Publication-ready |
| Part 2 | β Standard | Publication-ready |
| Part 3 | β οΈ Partially rechecked | Development only |
Migration to Other Clusters
1. Transfer Package
tar -czf benchmark_shuffled.tar.gz benchmark_shuffled/
scp benchmark_shuffled.tar.gz user@cluster:/data/benchmarks/
ssh user@cluster "cd /data/benchmarks/ && tar -xzf benchmark_shuffled.tar.gz"
2. Install Dependencies
pip install transformers>=4.40.0 torch>=2.0.0 qwen-vl-utils
3. Run Evaluation
python your_eval_script.py --data benchmark_shuffled/part1_long_videos_all.json
Citation
@dataset{cambrian_w_2025,
title={Cambrian-W: Panoramic Video Understanding Benchmark},
year={2025},
note={Shuffled Correct Order, Dual Format Version}
}
File Manifest
benchmark_shuffled/
βββ README.md # This file
βββ part1_long_videos_all.json # 40 videos
βββ part2_short_place_motion.json # 426 videos
βββ part3_short_objects.json # 426 videos
Key Points for Implementation
- Fixed Labels:
subset_conceptsorder determines A, B, C, D labels - Shuffled Order:
correct_orderis temporal sequence (randomized) - Answer Mapping: Answer is sequence of labels based on
correct_order - No Position Bias: Model cannot simply output "ABCD"
Example Verification:
concepts = ['signpost', 'shipping container', 'fire hydrant', 'tower']
# Labels: A=signpost, B=shipping container, C=fire hydrant, D=tower
correct_order = ['shipping container', 'tower', 'signpost', 'fire hydrant']
# Temporal: B β D β A β C
answer = 'BDAC'
# Expected answer
# Verify
label_map = {c: chr(ord('A')+i) for i, c in enumerate(concepts)}
expected = ''.join([label_map[c] for c in correct_order])
assert answer == expected # 'BDAC' == 'BDAC' β
Ready for cluster deployment! π