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Beyond8Bits: Seeing Beyond 8 Bits

Subjective and Objective Quality Assessment of HDR-UGC Videos CVPR 2026

Shreshth Saini¹, Bowen Chen¹, Neil Birkbeck², Yilin Wang², Balu Adsumilli², Alan C. Bovik¹,³ ¹ Laboratory for Image and Video Engineering (LIVE), UT Austin  ·  ² Google / YouTube  ·  ³ University of Colorado Boulder

Project Page arXiv Paper PDF Supplementary PDF Dataset UT-Box GitHub License


TL;DR

Beyond8Bits is, to our knowledge, the largest crowdsourced HDR User-Generated Content (UGC) video quality dataset to date, paired with HDR-Q, the first multimodal large language mode[...]

Paper-reported (full) Publish-ready release
HDR source videos 6,861 (2,253 Crowd + 4,608 Vimeo) 5,917 (2,153 Crowd + 3,764 Vimeo)
Transcoded videos ~44,276 41,419 (12,918 Crowd + 22,584 Vimeo transcodes + 5,917 references)
Crowd ratings >1.5 M on Amazon Mechanical Turk ~1.46 M
Avg. ratings per video ~35 ~35
Resolutions 360p / 720p / 1080p (+ source) same
Bitrate ladder 0.2 – 5 Mbps 0.2 / 0.5 / 1 / 2 / 3 Mbps
Rating instrument Continuous 0–100 Likert, ITU-R BT.500-14 same
Split 70 / 20 / 10 (train / val / test), by source 70 / 10 / 20 (28,987 / 4,151 / 8,281)
MOS aggregation SUREAL MLE; median inter-subject SRCC 0.90 same

Repository layout

Beyond8Bits/
├── index.html                         # Project page (hosted via GitHub Pages)
├── images_data.json                   # Carousel: frame paths + predicted / MOS scores
├── static/
│   ├── css/                           # bulma + project stylesheet
│   ├── js/                            # fontawesome
│   ├── images/                        # overview figure, distribution plots, AMT UI
│   └── pdfs/                          # paper & supplementary (drop-in once camera-ready)
├── images/
│   └── sample_frames/                 # 99 sample HDR frames used by the page carousel
└── data/
    ├── Beyond8Bits_publish.csv        # Full release: 41,419 transcoded clips × 12 columns
    ├── Beyond8Bits_publish.txt        # Matching list of 41,419 hashed video IDs
    ├── Beyond8Bits_publish_crowd.csv  # CHUG-compatible crowd-only subset (5,992 rows)
    └── Beyond8Bits_publish_crowd.txt  # Matching crowd-only ID list

Per-rating raw CSVs and the full archive live on UT-Box: https://utexas.box.com/s/pvz8zpmpogvpy62pqpar2e54c6ovyd5z


Per-video metadata schema

data/Beyond8Bits_publish.csv (41,419 rows × 12 columns):

Column Description
video_id Hashed video ID (primary key, used for S3 download)
mos MOS after SUREAL bias-corrected aggregation
sos Standard-of-scores (SUREAL dispersion)
type Source partition, Crowd or Vimeo
ref 1 if source / reference video; 0 if transcoded
resolution Target resolution, 360p / 720p / 1080p / ref (source)
bitrate Target bitrate, 0.2M / 0.5M / 1M / 2M / 3M (or ref)
orientation Portrait or Landscape
framerate Native playback framerate (fps)
split train / validation / test (70 / 10 / 20 by source identity)
height Native frame height (px)
width Native frame width (px)

Per-rating raw CSVs are available via the UT-Box mirror linked above. See the paper Appendix E for the rating protocol.


Downloading the videos

Videos are hosted on an S3 mirror (s3://ugchdrmturk/videos/). You can use either the AWS CLI or stream directly in a browser.

# clone
git clone https://github.com/shreshthsaini/Beyond8Bits.git
cd Beyond8Bits

# single video
aws s3 cp s3://ugchdrmturk/videos/VIDEO_ID.mp4 ./Beyond8Bits_Videos/

# bulk: all 41,419 IDs in the published manifest
cat data/Beyond8Bits_publish.txt | while read video; do
  aws s3 cp s3://ugchdrmturk/videos/${video}.mp4 ./Beyond8Bits_Videos/
done

To stream a single video directly in the browser, replace VIDEO_ID in:

https://ugchdrmturk.s3.us-east-2.amazonaws.com/videos/VIDEO_ID.mp4

Example: https://ugchdrmturk.s3.us-east-2.amazonaws.com/videos/b882a56f87be722f24206e007c31ee4c.mp4


Loading the scores in Python

import pandas as pd

df = pd.read_csv("data/Beyond8Bits_publish.csv")
print(df.columns.tolist())
# ['video_id', 'mos', 'sos', 'type', 'ref', 'resolution',
#  'bitrate', 'orientation', 'framerate', 'split',
#  'height', 'width']

print(df["mos"].describe())          # MOS distribution
print(df["type"].value_counts())     # Crowd (15,071) vs Vimeo (26,348)
print(df["split"].value_counts())    # train / validation / test
print(df["resolution"].value_counts())  # ref / 360p / 720p / 1080p

Method summary: HDR-Q + HAPO

Paired with the dataset, we release HDR-Q, the first MLLM designed for HDR-UGC VQA.

  • HDR-aware vision encoder: a SigLIP-2 encoder adapted with HDR–SDR dual-domain contrastive supervision (captions generated by Qwen2.5-VL-72B). Frames stay at native 10-bit PQ / BT.2020;[...]
  • HAPO (HDR-Aware Policy Optimization): extends GRPO with three HDR-specific terms:
    • HDR–SDR contrastive KL: prevents modality neglect by contrasting rollouts with and without HDR tokens.
    • Dual-entropy regularization: per-pathway entropy penalties to avoid reward-hacking via entropy inflation.
    • High-Entropy Weighting (HEW): rescales group-normalized advantage with per-token entropy, focusing gradients on informative reasoning tokens.
  • Rewards: Gaussian-weighted MOS regression reward R_sc + format reward R_fmt + group-level self-reward R_self.
  • Backbone + compute: Ovis2.5 base with rank-4 LoRA adapters; 8 uniformly-sampled frames per clip; trained on 4× NVIDIA H200 GPUs; two-stage RL (modality alignment → full RFT).

License

  • Metadata, CSV and TXT manifests, and the website code: CC BY 4.0, as stated in the paper. Use, share, and build on them with attribution.
  • Video payloads keep their original terms: CC-licensed Vimeo content, and crowd-contributed videos released under a non-exclusive research redistribution agreement (non-commercial research use). For commercial use of the videos, reach out.

Citation

@InProceedings{Saini_2026_CVPR,
    author    = {Saini, Shreshth and Chen, Bowen and Wang, Yilin and Birkbeck, Neil and Adsumilli, Balu and Bovik, Alan C.},
    title     = {Seeing Beyond 8bits: Subjective and Objective Quality Assessment of HDR-UGC Videos},
    booktitle = {Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
    month     = {June},
    year      = {2026},
    pages     = {15538-15549}
}

Please also consider citing the predecessor sub-studies Beyond8Bits extends:

@INPROCEEDINGS{Saini_2025_ICIP_CHUG,
  author    = {Saini, Shreshth and Bovik, Alan C. and Birkbeck, Neil and Wang, Yilin and Adsumilli, Balu},
  booktitle = {2025 IEEE International Conference on Image Processing (ICIP)},
  title     = {CHUG: Crowdsourced User-Generated HDR Video Quality Dataset},
  year      = {2025},
  pages     = {2504-2509},
  doi       = {10.1109/ICIP55913.2025.11084488}
}

@InProceedings{Saini_2026_WACV_BrightRate,
    author    = {Saini, Shreshth and Chen, Bowen and Wang, Yilin and Birkbeck, Neil and Adsumilli, Balu and Bovik, Alan C.},
    title     = {BrightRate: Quality Assessment for User-Generated HDR Videos},
    booktitle = {Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV)},
    month     = {March},
    year      = {2026},
    pages     = {1522-1532}
}

Contact

Main PoC: Shreshth Saini, saini.2 at utexas.edu · website · Google Scholar

Future Data Maintainer: Pragyadipta Adhya, pragyadipta.adhya at colorado.edu · website · Google Scholar