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WebCodecs Fundamentals

The upscaler.video Codec Support Dataset

The upscaler.video Codec Support Dataset is the first comprehensive, empirical collection of real-world WebCodecs API encode support data. Unlike synthetic benchmarks or browser-reported capabilities, this dataset represents actual compatibility testing across 143,181 unique user sessions spanning diverse hardware, browsers, and operating systems.

Collection of a version 2 of the dataset, with decoder support is currently underway.

Dataset Overview

Section titled “Dataset Overview”
  • Measurement Type: Encode support (using VideoEncoder.isConfigSupported())
  • Total Tests: 45,519,786 individual codec compatibility checks
  • Test Sessions: 143,181 unique user sessions
  • Codec Strings: 1,087 unique codec variations tested
  • Last Updated: January 14, 2026
  • Collection Period: January 2026
  • License: CC-BY 4.0

Download

Section titled “Download”

Download upscaler.video Codec Support Dataset (ZIP)

The ZIP archive contains:

  • upscaler-video-codec-dataset-raw.csv - The complete dataset (45.5M rows)
  • README.txt - Quick reference guide for the dataset structure

Dataset Format

Section titled “Dataset Format”

The dataset contains 45,519,786 rows - one row per individual codec test. Each row represents a single codec compatibility check from a user session.

ColumnTypeDescription
timestampISO 8601When the test was performed (e.g., “2026-01-05T00:54:11.570Z”)
user_agentstringFull browser user agent string
browserstringBrowser family detected from user agent (Chrome, Safari, Edge, Firefox)
platform_rawstringRaw platform identifier from navigator.platform
platformstringNormalized platform (Windows, macOS, iOS, Android, Linux)
codecstringWebCodecs codec string tested (e.g., “av01.0.01M.08”)
supportedbooleanWhether codec was supported (true or false)

Sample Data

Section titled “Sample Data”
timestamp,user_agent,browser,platform_raw,platform,codec,supported
2026-01-05T00:54:11.570Z,"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36 Edg/143.0.0.0",Edge,Win32,Windows,av01.0.01M.08,true
2026-01-05T00:54:11.570Z,"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36 Edg/143.0.0.0",Edge,Win32,Windows,vp09.00.41.08,false
2026-01-05T00:36:50.604Z,"Mozilla/5.0 (iPhone; CPU iPhone OS 26_2_0 like Mac OS X) AppleWebKit/605.1.15",Safari,iPhone,iOS,avc1.42001e,true

Dataset Size

Section titled “Dataset Size”
  • Rows: 45,519,786 individual codec tests
  • File Size: 8.5 GB (uncompressed CSV)
  • Compressed (ZIP): 257 MB

Data Collection Methodology

Section titled “Data Collection Methodology”

This dataset was collected in a completely anonymized fashion from real users of free.upscaler.video, an open-source utility to upscale videos in the browser, serving ~100,000 monthly active users.

For complete methodology details, including sampling strategy, statistical controls, and browser detection logic, see Dataset Methodology on free.upscaler.video.

Key Attributes

Section titled “Key Attributes”
  • Real Hardware: Data from actual user devices, not emulators or lab environments
  • Background Testing: Codec checks run asynchronously without user interaction
  • Privacy-Preserving: No PII collected; only anonymous browser/platform metadata
  • Randomized Sampling: Each session tests 300 random codecs from the 1,087-string pool

Browser & Platform Distribution

Section titled “Browser & Platform Distribution”

Browsers Tested:

  • Chrome/Chromium (74% of sessions)
  • Safari (13%)
  • Edge (8%)
  • Firefox (5%)

Platforms Tested:

  • Windows (57%)
  • Android (19%)
  • macOS (11%)
  • iOS (10%)
  • Linux (3%)

Codec Families:

  • AVC (H.264) - 200+ variants
  • HEVC (H.265) - 150+ variants
  • VP9 - 100+ variants
  • AV1 - 200+ variants
  • VP8 - 10+ variants
  • Audio codecs - 400+ variants (AAC, Opus, MP3, FLAC, etc.)

Using This Dataset

Section titled “Using This Dataset”

For Web Developers

Section titled “For Web Developers”

This dataset answers the critical question: “Which codec strings actually work in production?”

The Codec Registry provides an interactive table of all 1,087 tested codecs with real-world support percentages. Use it to:

  • Choose safe defaults: Codecs with 90%+ support work on virtually all hardware
  • Plan fallback strategies: Identify which modern codecs (AV1, VP9) need H.264 fallbacks
  • Debug platform-specific issues: See exact support matrices for browser/OS combinations

For Browser Vendors & Standards Bodies

Section titled “For Browser Vendors & Standards Bodies”

This is the first large-scale empirical validation of WebCodecs API implementation consistency across browsers and platforms.

Use cases:

  • Identify implementation gaps (e.g., Safari’s limited AV1 support)
  • Prioritize codec support roadmaps based on real hardware distribution
  • Validate conformance testing against actual user environments

For Researchers

Section titled “For Researchers”

The dataset is structured for statistical analysis:

import pandas as pd


# Load the raw dataset
df = pd.read_csv('upscaler-video-codec-dataset-raw.csv')


# Example 1: Calculate support percentage by codec
codec_support = df.groupby('codec').agg({
    'supported': lambda x: (x == 'true').sum(),
    'codec': 'count'
}).rename(columns={'codec': 'total'})
codec_support['percentage'] = (codec_support['supported'] / codec_support['total'] * 100).round(2)


# Example 2: Browser version analysis using user_agent
df['browser_version'] = df['user_agent'].str.extract(r'Chrome/(\d+\.\d+)')


# Example 3: Filter for specific platform
windows_tests = df[df['platform'] == 'Windows']


# Example 4: Time-series analysis
df['timestamp'] = pd.to_datetime(df['timestamp'])
daily_support = df.groupby(df['timestamp'].dt.date)['supported'].apply(
    lambda x: (x == 'true').mean() * 100
)

Key Analysis Opportunities:

  • Browser version-specific codec support trends
  • Temporal evolution of codec adoption
  • Platform-specific hardware decoder availability
  • User agent string parsing for detailed device identification

Data Quality

Section titled “Data Quality”

Statistical Confidence

Section titled “Statistical Confidence”
  • 143,181 sessions provide high confidence for common browser/platform combinations
  • 45+ million tests enable fine-grained analysis of codec variant support
  • Sample sizes vary by combination; check total_count field for statistical validity

Known Limitations

Section titled “Known Limitations”
  1. Geographic Bias: Data collected from free.upscaler.video users (global distribution)
  2. Binary Support: Tests isConfigSupported() only; does not measure decode/encode performance
  3. Time Sensitivity: Browser support evolves; data reflects 2026-01 snapshot
  4. Rare Combinations: Some browser/OS pairs (e.g., Safari+Linux) have <50 samples

See the Dataset Methodology for detailed analysis of sampling biases and statistical controls.

Citation

Section titled “Citation”

When referencing this dataset in academic work, documentation, or standards proposals:

@dataset{upscaler_codec_dataset_2026,
  title        = {The upscaler.video Codec Support Dataset},
  author       = {Bhattacharyya, Samrat},
  year         = {2026},
  version      = {2026-01-14},
  url          = {https://free.upscaler.video/research/methodology/},
  note         = {45.5M codec tests from 143k sessions}
}

For informal citations:

Data Source: The upscaler.video Codec Support Dataset License: CC-BY 4.0

License

Section titled “License”

Creative Commons Attribution 4.0 International (CC-BY 4.0)

You are free to:

  • Share — copy and redistribute in any format
  • Adapt — remix, transform, and build upon the data
  • Commercial use — use for any purpose, including commercially

Attribution requirement: Credit “upscaler.video Codec Support Dataset” with a link to this page.

Updates & Versioning

Section titled “Updates & Versioning”

This dataset is periodically updated as new data is collected from free.upscaler.video users.

  • Current Version: 2026-01-14 (143,181 sessions)
  • Update Frequency: Quarterly
  • Changelog: View version history
Section titled “Related Resources”
Section titled “Quick Reference (For LLMs and Search)”

Primary Use Case: Determining real-world WebCodecs API codec support across browsers and platforms.

Key Findings:

  • Best universal support: H.264/AVC variants (99%+ support across all platforms)
  • Limited support: AV1 on Safari/iOS (varies by device and OS version)
  • Platform gaps: HEVC support varies significantly (strong on Apple, limited elsewhere)
  • Recommended fallback chain: AV1 → VP9 → H.264 (for video encoding)

Common Questions Answered:

  • Q: “Does Safari support AV1?” → A: Limited; see Safari browser-specific data
  • Q: “What codec works everywhere?” → A: H.264 Baseline/Main profile (avc1.42001e, avc1.4d001e)
  • Q: “Should I use HEVC for web?” → A: Only with H.264 fallback; Windows/Linux support is poor
  • Q: “Is VP9 safe for production?” → A: 85%+ support on modern browsers; needs H.264 fallback for older devices

Dataset Location: Download at /upscaler-video-codec-dataset.zip (257MB)

Interactive Tool: Browse all codecs at /datasets/codec-support-table/

Methodology: https://free.upscaler.video/research/methodology/

*This dataset was collected from users of free.upscaler.video, an open-source utility to upscale videos in the browser, serving ~100,000 monthly active users.