EDID Binary Files Reference

EDID (Extended Display Identification Data) is a binary data structure that describes a display’s capabilities. The Virtual Display Driver can use custom EDID files to precisely control how it appears to Windows and applications.

Purpose: Custom EDID files allow you to make your virtual display appear as a specific monitor model, with exact capabilities matching real hardware.

EDID File Format

Basic Structure

An EDID file is a binary file with a specific structure:

Minimum Size: 128 bytes (base EDID block)
Extended Size: 256 bytes (base EDID + one extension block)
Maximum Size: 512 bytes (base EDID + up to 3 extension blocks)

Common Configuration: 256 bytes (128-byte base + 128-byte CEA extension)The CEA extension block is required for HDMI features like HDR support.

EDID Block Structure

Show Base EDID Block (128 bytes)

Offset	Size	Description
0-7	8	Header (fixed: `00 FF FF FF FF FF FF 00`)
8-9	2	Manufacturer ID (compressed 3-letter code)
10-11	2	Product ID code
12-15	4	Serial number
16	1	Week of manufacture
17	1	Year of manufacture (offset from 1990)
18	1	EDID version (usually 0x01)
19	1	EDID revision (usually 0x03 or 0x04)
20-24	5	Video input parameters
25-34	10	Color characteristics (chromaticity)
35-37	3	Established timings
38-53	16	Standard timings (8 entries × 2 bytes)
54-125	72	Detailed timing descriptors (4 × 18 bytes)
126	1	Extension block count
127	1	Checksum

Show CEA Extension Block (128 bytes)

The CEA-861 extension block provides HDMI/HDTV capabilities:

Offset	Size	Description
0	1	Extension tag (0x02 for CEA)
1	1	Revision number (typically 0x03)
2	1	Offset to detailed timing descriptors
3	1	Support flags (audio, YCbCr, etc.)
4-n	var	Data block collection (video, audio, vendor)
n-126	var	Detailed timing descriptors
127	1	Checksum

Key Data Blocks:

Video Data Block: Supported video formats (VICs)
Audio Data Block: Audio capabilities
Vendor Specific Block: HDMI capabilities, HDR metadata
Extended Tag Blocks: HDR Static Metadata, Colorimetry

Using Custom EDID Files

File Location

Place your custom EDID file in the driver installation directory:

C:\VirtualDisplayDriver\user_edid.bin

File Name: The file must be named exactly user_edid.bin (case-sensitive on some systems).

Enable Custom EDID

Configure vdd_settings.xml to use the custom EDID:

<edid>
  <CustomEdid>true</CustomEdid>
  <PreventSpoof>false</PreventSpoof>
  <EdidCeaOverride>false</EdidCeaOverride>
</edid>

Configuration Options

CustomEdid

boolean

default:"false"

Enable loading of user_edid.bin.When false, the driver uses its hardcoded EDID.

PreventSpoof

boolean

default:"false"

Prevent modification of the manufacturer ID.

false - Driver may modify manufacturer ID (default behavior)
true - Preserve original manufacturer ID from the EDID file

EdidCeaOverride

boolean

default:"false"

Replace CEA extension block with driver’s hardcoded HDR-capable CEA block.Use Cases:

Adding HDR support to a 128-byte EDID
Fixing broken CEA extensions
Ensuring HDR metadata is present

If your custom EDID is 128 bytes and you need HDR, set EdidCeaOverride to true. The driver will append its HDR-capable CEA extension.

Creating Custom EDID Files

Method 1: Extract from Real Monitor

The most reliable method is extracting EDID from a real monitor.

Extract EDID in Windows

Option A: Device Manager

Open Device Manager
Expand “Monitors”
Right-click your monitor → Properties
Go to “Details” tab
Select “Device Instance Path”
Note the path (e.g., DISPLAY\DEL1234\...)

Option B: PowerShell

Get-WmiObject WmiMonitorDescriptorMethods -Namespace root\wmi | 
  ForEach-Object { $_.WmiGetMonitorRawEEdidV1Block(0) }

Save EDID to File

Use a third-party tool like:

MonitorInfoView (NirSoft)
EDID Reader (Analog Way)
Custom Resolution Utility (CRU)

Export as binary (.bin) file

Validate EDID

Verify the EDID is valid:

Check file size (128, 256, 384, or 512 bytes)
Verify header: 00 FF FF FF FF FF FF 00
Confirm checksum is correct

Copy to Driver Directory

Save as user_edid.bin in driver installation directory

Method 2: Use Included Sample EDIDs

The driver includes sample EDID files in the EDID/ directory:

EDID/
├── lolhero_edid.bin      - Gaming monitor EDID
├── digihome_edid.bin     - Standard display EDID
└── 8K240HzHDR.edid       - 8K HDR display EDID

To use a sample EDID:

copy "C:\VirtualDisplayDriver\EDID\8K240HzHDR.edid" "C:\VirtualDisplayDriver\user_edid.bin"

Method 3: Create from Scratch

For advanced users, create custom EDID using specialized tools.

Complexity: Creating EDID from scratch requires deep understanding of the EDID specification. Errors can cause driver instability.

Recommended Tools:

Custom Resolution Utility (CRU) - Windows EDID editor
wxEDID - Cross-platform EDID editor
EDID Designer - Professional EDID creation tool

Basic Workflow:

Start with a template EDID from a similar monitor
Modify manufacturer, model, and serial information
Add/remove supported resolutions
Configure HDR metadata in CEA extension
Update checksums (critical!)
Test thoroughly

EDID Validation and Checksum

EDID blocks include checksums to ensure data integrity.

Checksum Calculation

For each 128-byte block:

checksum = (256 - (sum of bytes 0-126) % 256) % 256

The checksum is stored in byte 127 of each block.

Driver Validation

The driver validates custom EDID files:

Size Check: File must be 128, 256, 384, or 512 bytes
Header Check: First 8 bytes must be 00 FF FF FF FF FF FF 00
Checksum Validation: Each block’s checksum must be correct
Structure Validation: Extension count must match actual extensions

Automatic Checksum: The driver automatically recalculates and updates the checksum after loading, so minor checksum errors may be corrected.

HDR Support in EDID

For HDR support, the CEA extension must include specific data blocks.

Required CEA Data Blocks for HDR

Show HDR Static Metadata Data Block (Extended Tag 0x06)

Extended Tag: 0x06
Length: 5-7 bytes

Byte 0: Extended tag (0x06)
Byte 1: EOTF support bitmap
  Bit 0: Traditional Gamma SDR
  Bit 1: Traditional Gamma HDR
  Bit 2: SMPTE ST 2084 (PQ) - Required for HDR10
  Bit 3: Hybrid Log-Gamma (HLG)
Byte 2: Static Metadata Type support
  Bit 0: Static Metadata Type 1 - Required for HDR10
Byte 3: Desired Max Luminance (optional)
Byte 4: Desired Max Frame-Average Luminance (optional)
Byte 5: Desired Min Luminance (optional)

Example HDR10 Support:

06 06 05 01 50 26 12
^
└─ Extended Data Block length (7 bytes total)
- Extended tag (HDR Static Metadata)
- EOTF: SDR Gamma + PQ
- Metadata Type 1 supported
- Max Luminance
- Max Frame-Average Luminance
- Min Luminance
- (varies)

Show Colorimetry Data Block (Extended Tag 0x05)

Defines supported color spaces:

Extended Tag: 0x05
Length: 2 bytes

Byte 0: Extended tag (0x05)
Byte 1: Colorimetry support bitmap
  Bit 0: xvYCC601
  Bit 1: xvYCC709
  Bit 2: sYCC601
  Bit 3: Adobe YCC601
  Bit 4: Adobe RGB
  Bit 5: BT2020 cYCC
  Bit 6: BT2020 YCC
  Bit 7: BT2020 RGB

Example Wide Gamut Support:

03 05 E0
^
└─ Extended Data Block length (3 bytes total)
   05 - Extended tag (Colorimetry)
   E0 - Supports BT2020 RGB, YCC, cYCC

HDR-Capable EDID Example Structure

A minimal HDR-capable EDID (256 bytes) includes:

Base EDID Block (128 bytes):
- Standard monitor information
- Color characteristics (chromaticity)
- Extension count = 1
CEA Extension Block (128 bytes):
- Video Data Block (supported resolutions)
- HDR Static Metadata Data Block (tag 0x06)
- Colorimetry Data Block (tag 0x05)
- Detailed timing descriptors

Troubleshooting Custom EDID

EDID Not Loading

Symptoms: Driver uses default EDID despite CustomEdid set to true Solutions:

Check File Location and Name

File must be named exactly user_edid.bin
File must be in driver installation directory (usually C:\VirtualDisplayDriver\)
Check file permissions (driver must have read access)

Verify File Size

Valid sizes are 128, 256, 384, or 512 bytes only.Check file size:

(Get-Item "C:\VirtualDisplayDriver\user_edid.bin").Length

Validate EDID Structure

First 8 bytes must be: 00 FF FF FF FF FF FF 00
Check with hex editor
Verify checksum is correct

Check Driver Logs

Enable logging in vdd_settings.xml:

<logging>
  <logging>true</logging>
  <debuglogging>true</debuglogging>
</logging>

Look for EDID-related error messages in the log file.

Checksum Errors

Symptoms: Driver reports “Custom edid failed due to invalid checksum” Solution: Recalculate and update checksums

import sys

def calculate_edid_checksum(block):
    """Calculate EDID checksum for 128-byte block"""
    if len(block) != 128:
        raise ValueError("Block must be 128 bytes")
    
    # Sum first 127 bytes
    total = sum(block[:127])
    
    # Checksum makes total sum to 0 (mod 256)
    checksum = (256 - (total % 256)) % 256
    return checksum

def fix_edid_checksums(filename):
    """Read EDID, fix checksums, write back"""
    with open(filename, 'rb') as f:
        data = bytearray(f.read())
    
    if len(data) % 128 != 0:
        print(f"Error: File size must be multiple of 128 bytes")
        return False
    
    # Process each 128-byte block
    for i in range(0, len(data), 128):
        block = data[i:i+128]
        checksum = calculate_edid_checksum(block)
        data[i+127] = checksum
        print(f"Block {i//128}: Checksum = 0x{checksum:02X}")
    
    # Write corrected EDID
    with open(filename, 'wb') as f:
        f.write(data)
    
    print(f"Checksums fixed: {filename}")
    return True

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python fix_edid.py <edid_file.bin>")
        sys.exit(1)
    
    fix_edid_checksums(sys.argv[1])

HDR Not Working

Symptoms: Custom EDID loads but HDR is not available in Windows Checklist:

CEA extension block present (256-byte EDID minimum)
HDR Static Metadata Data Block included (Extended Tag 0x06)
EOTF byte includes bit 2 (SMPTE ST 2084 / PQ)
Static Metadata Type 1 supported (bit 0 of metadata byte)
Colorimetry Data Block present (Extended Tag 0x05)
hdr10_static_metadata.enabled = true in vdd_settings.xml

Quick Fix: Set EdidCeaOverride to true to replace the CEA extension with the driver’s HDR-capable version:

<edid>
  <CustomEdid>true</CustomEdid>
  <EdidCeaOverride>true</EdidCeaOverride>
</edid>

EDID Analysis Tools

Included Parser Utility

The driver includes an EDID parser for analysis:

cd "C:\VirtualDisplayDriver\EDID"
EDIDParser.exe user_edid.bin

Outputs:

Detected video modes
HDR capabilities (HDR10, Dolby Vision, HDR10+)
Color profile information
Generated monitor_profile.xml

See EDID Parser Reference for details.

Online EDID Decoders

EDID Decoder (edid.tv) - Web-based EDID analyzer
Analog Way EDID Editor - Professional EDID tool
Phoenix EDID Designer - Commercial EDID editor

Hex Editors

For manual EDID editing:

HxD (Windows) - Free hex editor
010 Editor (Cross-platform) - Advanced hex editor with EDID template
Hex Fiend (macOS) - Fast hex editor

Best Practices

Start with Real EDID

Always start with an EDID extracted from a real monitor. This ensures proper structure and valid data.

Test Incrementally

Make small changes and test after each modification. This helps identify problematic changes.

Validate Checksums

Always recalculate checksums after editing. Invalid checksums cause the driver to reject the EDID.

Keep Backups

Maintain backups of working EDID files before making changes.

Use CEA Override

For HDR support, consider using EdidCeaOverride instead of manually creating CEA extensions.

Document Changes

Keep notes on modifications made to custom EDIDs for troubleshooting.

vdd_settings.xml

Main configuration file reference

Monitor Profile XML

XML EDID profile format

EDID Parser Utility

Parse and analyze EDID files

Custom EDID Guide

Step-by-step custom EDID creation

Configuration Reference

PowerShell Scripts

Utilities

Driver API

​EDID Binary Files Reference

​EDID File Format

​Basic Structure

​EDID Block Structure

​Using Custom EDID Files

​File Location

​Enable Custom EDID

​Configuration Options

​Creating Custom EDID Files

​Method 1: Extract from Real Monitor

​Method 2: Use Included Sample EDIDs

​Method 3: Create from Scratch

​EDID Validation and Checksum

​Checksum Calculation

​Driver Validation

​HDR Support in EDID

​Required CEA Data Blocks for HDR

​HDR-Capable EDID Example Structure

​Troubleshooting Custom EDID

​EDID Not Loading

​Checksum Errors

​HDR Not Working

​EDID Analysis Tools

​Included Parser Utility

​Online EDID Decoders

​Hex Editors

​Best Practices

Start with Real EDID

Test Incrementally

Validate Checksums

Keep Backups

Use CEA Override

Document Changes

​Related Documentation

vdd_settings.xml

Monitor Profile XML

EDID Parser Utility

Custom EDID Guide

Build docs developers (and LLMs) love

EDID Binary Files Reference

EDID File Format

Basic Structure

EDID Block Structure

Using Custom EDID Files

File Location

Enable Custom EDID

Configuration Options

Creating Custom EDID Files

Method 1: Extract from Real Monitor

Method 2: Use Included Sample EDIDs

Method 3: Create from Scratch

EDID Validation and Checksum

Checksum Calculation

Driver Validation

HDR Support in EDID

Required CEA Data Blocks for HDR

HDR-Capable EDID Example Structure

Troubleshooting Custom EDID

EDID Not Loading

Checksum Errors

HDR Not Working

EDID Analysis Tools

Included Parser Utility

Online EDID Decoders

Hex Editors

Best Practices

Related Documentation