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Overview

The EDID (Extended Display Identification Data) parser provides functionality to load and parse monitor profiles from XML files, enabling automatic configuration of display modes, HDR capabilities, and color profiles.

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Core Data Structures

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EdidProfileData

Stores parsed EDID profile information: 
struct EdidProfileData {
    vector<tuple<int, int, int, int>> modes;  // Display modes
    bool hdr10Supported = false;
    bool dolbyVisionSupported = false;
    bool hdr10PlusSupported = false;
    double maxLuminance = 0.0;
    double minLuminance = 0.0;
    wstring primaryColorSpace = L"sRGB";
    double gamma = 2.2;
    double redX = 0.64, redY = 0.33;
    double greenX = 0.30, greenY = 0.60;
    double blueX = 0.15, blueY = 0.06;
    double whiteX = 0.3127, whiteY = 0.3290;
    int preferredWidth = 1920;
    int preferredHeight = 1080;
    double preferredRefresh = 60.0;
};
Mode Tuple Format:
  • Element 0: Width (pixels)
  • Element 1: Height (pixels)
  • Element 2: Refresh rate multiplier (typically 1000)
  • Element 3: Nominal refresh rate (Hz)

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Key Functions

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LoadEdidProfile

Loads and parses an EDID profile from an XML file: 
bool LoadEdidProfile(const wstring& profilePath, EdidProfileData& profile);
Parameters:
  • profilePath: Relative path to the EDID profile XML file (relative to config directory)
  • profile: Output parameter to receive parsed profile data
Returns: true if profile loaded successfully, false otherwise. File Location: The function looks for the profile at C:\VirtualDisplayDriver\<profilePath> Example: 
EdidProfileData profile;
if (LoadEdidProfile(L"EDID/monitor_profile.xml", profile)) {
    // Profile loaded successfully
    vddlog("i", ("Loaded " + std::to_string(profile.modes.size()) + " modes").c_str());
}

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ApplyEdidProfile

Applies a loaded EDID profile to the driver configuration: 
bool ApplyEdidProfile(const EdidProfileData& profile);
Parameters:
  • profile: Loaded EDID profile data to apply
Returns: true if profile applied successfully, false if EDID integration is disabled. Functionality:
  • Merges EDID modes with manual configuration based on priority settings
  • Applies HDR metadata if enabled
  • Configures color primaries and color space settings
  • Generates gamma ramp configurations
  • Validates and optimizes final mode list

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XML Profile Format

EDID profiles are stored in XML format with the following structure: 
<?xml version="1.0"?>
<EdidProfile>
    <MonitorModes>
        <Mode>
            <Width>1920</Width>
            <Height>1080</Height>
            <RefreshRateMultiplier>1000</RefreshRateMultiplier>
            <NominalRefreshRate>60</NominalRefreshRate>
        </Mode>
        <!-- Additional modes -->
    </MonitorModes>
    
    <HDRCapabilities>
        <HDR10Supported>true</HDR10Supported>
        <DolbyVisionSupported>false</DolbyVisionSupported>
        <HDR10PlusSupported>false</HDR10PlusSupported>
        <MaxLuminance>1000.0</MaxLuminance>
        <MinLuminance>0.05</MinLuminance>
    </HDRCapabilities>
    
    <ColorProfile>
        <PrimaryColorSpace>sRGB</PrimaryColorSpace>
        <Gamma>2.2</Gamma>
        <RedX>0.64</RedX>
        <RedY>0.33</RedY>
        <GreenX>0.30</GreenX>
        <GreenY>0.60</GreenY>
        <BlueX>0.15</BlueX>
        <BlueY>0.06</BlueY>
        <WhiteX>0.3127</WhiteX>
        <WhiteY>0.3290</WhiteY>
    </ColorProfile>
    
    <PreferredMode>
        <Width>1920</Width>
        <Height>1080</Height>
        <RefreshRate>60.0</RefreshRate>
    </PreferredMode>
</EdidProfile>

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Mode Management Functions

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GenerateModesFromEdid

Generates and filters display modes from EDID profile based on configuration settings: 
vector<tuple<int, int, int, int>> GenerateModesFromEdid(const EdidProfileData& profile);
Filtering Criteria:
  • Resolution range (min/max width and height)
  • Refresh rate range (min/max refresh rate)
  • Fractional rates exclusion (optional)
  • Aspect ratio validation
Returns: Filtered and sorted list of display modes. Example: 
EdidProfileData profile;
LoadEdidProfile(L"EDID/monitor_profile.xml", profile);
vector<tuple<int, int, int, int>> modes = GenerateModesFromEdid(profile);
// Returns modes filtered by current driver settings

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FindPreferredModeFromEdid

Locates the preferred display mode from the EDID profile: 
tuple<int, int, int, int> FindPreferredModeFromEdid(
    const EdidProfileData& profile,
    const vector<tuple<int, int, int, int>>& availableModes
);
Parameters:
  • profile: EDID profile containing preferred mode information
  • availableModes: List of available modes to search
Returns: Preferred mode tuple, or fallback mode if preferred mode not found.

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MergeAndOptimizeModes

Merges manual and EDID modes based on priority settings: 
vector<tuple<int, int, int, int>> MergeAndOptimizeModes(
    const vector<tuple<int, int, int, int>>& manualModes,
    const vector<tuple<int, int, int, int>>& edidModes
);
Priority Modes:
  • "edid": Use only EDID modes
  • "manual": Use only manual modes
  • "combined": Merge both, removing duplicates
Returns: Merged mode list based on sourcePriority global setting.

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OptimizeModeList

Optimizes the final mode list for performance and compatibility: 
vector<tuple<int, int, int, int>> OptimizeModeList(
    const vector<tuple<int, int, int, int>>& modes,
    const tuple<int, int, int, int>& preferredMode
);
Optimizations:
  • Places preferred mode first in the list
  • Removes duplicate modes
  • Limits total modes to 32 for optimal performance
  • Sorts by resolution and refresh rate

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ValidateModeList

Validates a mode list and generates diagnostic report: 
bool ValidateModeList(const vector<tuple<int, int, int, int>>& modes);
Validation Checks:
  • Non-empty mode list
  • Resolution distribution analysis
  • Refresh rate variety
  • Preferred mode confirmation
Returns: true if validation passes, false otherwise.

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HDR Metadata Conversion

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ConvertEdidToSmpteMetadata

Converts EDID profile data to SMPTE ST.2086 HDR metadata format: 
VddHdrMetadata ConvertEdidToSmpteMetadata(const EdidProfileData& profile);
Conversion:
  • Chromaticity coordinates: 0.0-1.0 → 0-50000 (SMPTE format)
  • Luminance values: nits → 0.0001 cd/m² units
  • Content light levels from configuration settings
Example: 
EdidProfileData profile;
LoadEdidProfile(L"EDID/monitor_profile.xml", profile);
VddHdrMetadata metadata = ConvertEdidToSmpteMetadata(profile);
if (metadata.isValid) {
    // Use metadata for HDR display configuration
}

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Color Space Conversion

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ConvertEdidToGammaRamp

Generates gamma ramp from EDID color profile: 
VddGammaRamp ConvertEdidToGammaRamp(const EdidProfileData& profile);
Supported Color Spaces:
  • sRGB (gamma 2.2)
  • DCI-P3 (gamma 2.4)
  • Rec.2020 (gamma 2.4)
  • Adobe RGB (gamma 2.2)
Returns: VddGammaRamp structure with gamma value, color space, and optional 3x4 transformation matrix.

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Configuration Settings

EDID integration behavior is controlled by global settings: 
// Enable/disable EDID integration
bool edidIntegrationEnabled = false;

// Auto-configure from EDID
bool autoConfigureFromEdid = false;

// EDID profile path
wstring edidProfilePath = L"EDID/monitor_profile.xml";

// Override manual settings with EDID data
bool overrideManualSettings = false;

// Fall back to manual settings on error
bool fallbackOnError = true;

// Auto resolutions from EDID
bool autoResolutionsEnabled = false;

// Source priority for mode merging
wstring sourcePriority = L"manual";  // "edid", "manual", or "combined"

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Error Handling

All EDID functions include comprehensive error handling:
  • File not found: Returns false, logs warning
  • XML parsing errors: Returns false, logs error with details
  • Invalid data values: Uses defaults, logs warning
  • Empty mode list: Falls back to manual configuration

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References

  • Source File: ~/workspace/source/Virtual Display Driver (HDR)/MttVDD/Driver.cpp (lines 661-1301)
  • EDID Standard: VESA Enhanced Extended Display Identification Data Standard
  • SMPTE ST.2086: Mastering Display Color Volume Metadata

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