16. Appendices#

16.1 DirectShow Property Constants#

  • Camera Properties (IAMCameraControl)

    • Pan (0)

    • Tilt (1)

    • Roll (2)

    • Zoom (3)

    • Exposure (4)

    • Iris (5)

    • Focus (6)

    • ScanMode, Privacy, PanRelative, etc.

  • Video Properties (IAMVideoProcAmp)

    • Brightness (0)

    • Contrast (1)

    • Hue (2)

    • Saturation (3)

    • Sharpness (4)

    • Gamma, ColorEnable, WhiteBalance, etc.

Each enum value maps directly to the property index used in native DirectShow APIs and the corresponding duvc-ctl constants. See camera.h, capability.h, and constants.h for full code listings.

16.2 Error Code Reference#

  • Common duvc-ctl Error Codes:

    • E_NOTIMPL: Operation not implemented on this platform or device.

    • E_FAIL: General DirectShow or Windows error, see decoded HRESULT.

    • E_PROPERTY_UNSUPPORTED: Queried property is not supported by the camera hardware.

    • E_DEVICE_NOT_FOUND: No matching device found.

    • E_INVALID_ARG: An API was called with an invalid argument or out-of-range value.

All error handling goes through duvc-ctl’s typed Result<T> and Error objects, which also retain decoded Windows HRESULT, details, and (where possible) string diagnostics for troubleshooting. Refer to result.h and error handling snippets for API usage.

16.3 GUID Reference#

  • DirectShow Class and Interface GUIDs

    • CLSID_SystemDeviceEnum

    • CLSID_VideoInputDeviceCategory

    • IID_IAMCameraControl: {C6E13370-30AC-11d0-A18C-00A0C9118956}

    • IID_IAMVideoProcAmp: {C6E13360-30AC-11d0-A18C-00A0C9118956}

    • IID_IKsPropertySet: {31efac30-515c-11d0-a9aa-00aa0061be93}

These GUIDs are defined in windows_internal.h and core implementation files and are required for COM interface acquisition and property control calls.

16.4 Glossary#

  • UVC: USB Video Class, the industry standard for USB camera communication and control.

  • DirectShow: Microsoft’s legacy multimedia framework/APIs for media capture, processing, and streaming on Windows.

  • COM: Component Object Model; Windows technology underpinning all DirectShow interfaces.

  • IAMCameraControl/IAMVideoProcAmp: DirectShow interfaces for adjusting camera/video properties.

  • Vendor Extension: Device-specific controls not defined by the UVC spec, such as Logitech’s FaceTracking.

  • HRESULT: Standard Windows error/status code used by COM and API calls, convertible to codes and messages in duvc-ctl results.

  • GUID: Globally unique identifier, a 128-bit value identifying COM interfaces and DirectShow categories.

All terminology aligns with the Windows SDK, UVC spec, or something called common sense