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How To Implement Extended Camera Control Properties

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The camera driver should implement extended camera control properties as individual property sets—that is, each property should be implemented as a single property set. The following example code can be used as a starting point for implementing these properties.

Note  Because an extended property’s data size can be of arbitrary length, query the user-mode stack for the size of the data by passing a null buffer. A two-step process is needed: first the driver returns the required length, as shown in the example code, then the user-mode stack requests a proper buffer for the property data.

Driver implementation

DEFINE_KSPROPERTY_TABLE(SocSimFilterFocusPropertyItems)
{       
    DEFINE_KSPROPERTY_ITEM(
        0,
        CCaptureFilter::FocusRectHandler,
        sizeof(KSPROPERTY),
        0,
        CCaptureFilter::FocusRectHandler,
        NULL, 0, NULL, NULL, 0
        )
};

DEFINE_KSPROPERTY_TABLE(SocSimFilterVideoStabPropertyItems)
{       
    DEFINE_KSPROPERTY_ITEM(
        0,
        CCaptureFilter::VideoStabilizationModeHandler,
        sizeof(KSPROPERTY),
        0,
        CCaptureFilter::VideoStabilizationModeHandler,
        NULL, 0, NULL, NULL, 0
        )
};

DEFINE_KSPROPERTY_TABLE(SocSimFilterFlashPropertyItems)
{       
    DEFINE_KSPROPERTY_ITEM(
        0,
        CCaptureFilter::FlashHandler,
        sizeof(KSPROPERTY),
        0,
        CCaptureFilter::FlashHandler,
        NULL, 0, NULL, NULL, 0
        )
};

DEFINE_KSPROPERTY_SET_TABLE(SocSimFilterPropertySets)
{
    DEFINE_KSPROPERTY_SET(
        &PROPSETID_VIDCAP_CAMERACONTROL_REGION_OF_INTEREST,
        SIZEOF_ARRAY(SocSimFilterFocusPropertyItems),
        SocSimFilterFocusPropertyItems,
        0,
        NULL),

    DEFINE_KSPROPERTY_SET(
        &PROPSETID_VIDCAP_CAMERACONTROL_FLASH,
        SIZEOF_ARRAY(SocSimFilterFlashPropertyItems),
        SocSimFilterFlashPropertyItems,
        0,
        NULL),

    DEFINE_KSPROPERTY_SET(
        &PROPSETID_VIDCAP_CAMERACONTROL_VIDEO_STABILIZATION,
        SIZEOF_ARRAY(SocSimFilterVideoStabPropertyItems),
        SocSimFilterVideoStabPropertyItems,
        0,
        NULL)

};

NTSTATUS
CCaptureFilter::FlashHandler(
    __in    PIRP Irp,
    __in    PKSPROPERTY Property,
    __inout PVOID pData
    )
{
    PAGED_CODE();
    NTSTATUS Status = STATUS_SUCCESS;
    NT_ASSERT(Irp);
    NT_ASSERT(Property);

    CCaptureFilter* pFilter = reinterpret_cast <CCaptureFilter*>(KsGetFilterFromIrp(Irp)->Context);

    PIO_STACK_LOCATION pIrpStack = IoGetCurrentIrpStackLocation(Irp);
    ULONG ulOutputBufferLength = pIrpStack->Parameters.DeviceIoControl.OutputBufferLength;
    ULONG InputBufferLength = pIrpStack->Parameters.DeviceIoControl.InputBufferLength;

    if (Property->Flags & KSPROPERTY_TYPE_SET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S))
        {
            PKSPROPERTY_CAMERACONTROL_FLASH_S pFlash = (PKSPROPERTY_CAMERACONTROL_FLASH_S)pData;
            pFilter->m_Flash = pFlash->Flash;
            pFilter->m_FlashCapabilites = pFlash->Capabilities;
            Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S);
        }
        else 
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }
    else if (Property->Flags & KSPROPERTY_TYPE_GET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S))
        {
            PKSPROPERTY_CAMERACONTROL_FLASH_S pFlash = (PKSPROPERTY_CAMERACONTROL_FLASH_S)pData;
            pFlash->Flash = pFilter->m_Flash;
            pFlash->Capabilities = pFilter->m_FlashCapabilites;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_FLASH_S);
            Status = STATUS_SUCCESS;
        }
        else
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }

    return Status;
}

NTSTATUS
CCaptureFilter::VideoStabilizationModeHandler(
    __in    PIRP Irp,
    __in    PKSPROPERTY Property,
    __inout PVOID pData
    )
{
    PAGED_CODE();
    NTSTATUS Status = STATUS_SUCCESS;
    NT_ASSERT(Irp);
    NT_ASSERT(Property);

    CCaptureFilter* pFilter = reinterpret_cast <CCaptureFilter*>(KsGetFilterFromIrp(Irp)->Context);

    PIO_STACK_LOCATION pIrpStack = IoGetCurrentIrpStackLocation(Irp);
    ULONG ulOutputBufferLength = pIrpStack->Parameters.DeviceIoControl.OutputBufferLength;
    ULONG InputBufferLength = pIrpStack->Parameters.DeviceIoControl.InputBufferLength;

    if (Property->Flags & KSPROPERTY_TYPE_SET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S))
        {
            PKSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S pVideoStab = (PKSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S)pData;
            pFilter->m_VideoStabMode = pVideoStab->VideoStabilizationMode;
            pFilter->m_VideoStabCapabilites = pVideoStab->Capabilities;
            Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S);
        }
        else 
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }
    else if (Property->Flags & KSPROPERTY_TYPE_GET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S))
        {
            PKSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S pVideoStab = (PKSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S)pData;
            pVideoStab->VideoStabilizationMode = pFilter->m_VideoStabMode;
            pVideoStab->Capabilities = pFilter->m_VideoStabCapabilites;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_VIDEOSTABILIZATION_MODE_S);
            Status = STATUS_SUCCESS;
        }
        else
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }

    return Status;
}

NTSTATUS
CCaptureFilter::FocusRectHandler(
    __in    PIRP Irp,
    __in    PKSPROPERTY Property,
    __inout PVOID pData
    )
{
    PAGED_CODE();
    NTSTATUS Status = STATUS_SUCCESS;
    NT_ASSERT(Irp);
    NT_ASSERT(Property);

    CCaptureFilter* pFilter = reinterpret_cast <CCaptureFilter*>(KsGetFilterFromIrp(Irp)->Context);

    PIO_STACK_LOCATION pIrpStack = IoGetCurrentIrpStackLocation(Irp);
    ULONG ulOutputBufferLength = pIrpStack->Parameters.DeviceIoControl.OutputBufferLength;
    ULONG InputBufferLength = pIrpStack->Parameters.DeviceIoControl.InputBufferLength;

    if (Property->Flags & KSPROPERTY_TYPE_SET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S))
        {
            PKSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S pFocusRect = (PKSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S)pData;
            pFilter->m_FocusRect.left = pFocusRect->FocusRect.left;
            pFilter->m_FocusRect.top = pFocusRect->FocusRect.top;
            pFilter->m_FocusRect.right = pFocusRect->FocusRect.right;
            pFilter->m_FocusRect.bottom = pFocusRect->FocusRect.bottom;
            pFilter->m_AutoFocusLock = pFocusRect->AutoFocusLock;
            pFilter->m_AutoExposureLock = pFocusRect->AutoExposureLock;
            pFilter->m_AutoWhitebalanceLock = pFocusRect->AutoWhitebalanceLock;
            Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S);
        }
        else 
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }
    else if (Property->Flags & KSPROPERTY_TYPE_GET)
    {
        if (ulOutputBufferLength == 0)
        {
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S);
            Status = STATUS_BUFFER_OVERFLOW;
        }
        else if (ulOutputBufferLength < sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S))
        {
            Status = STATUS_BUFFER_TOO_SMALL;
        }
        else if (pData && ulOutputBufferLength >= sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S))
        {
            PKSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S pFocusRect = (PKSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S)pData;
            pFocusRect->FocusRect.left = pFilter->m_FocusRect.left;
            pFocusRect->FocusRect.top = pFilter->m_FocusRect.top;
            pFocusRect->FocusRect.right = pFilter->m_FocusRect.right;
            pFocusRect->FocusRect.bottom = pFilter->m_FocusRect.bottom;
            pFocusRect->AutoFocusLock = pFilter->m_AutoFocusLock;
            pFocusRect->AutoExposureLock = pFilter->m_AutoExposureLock;
            pFocusRect->AutoWhitebalanceLock = pFilter->m_AutoWhitebalanceLock;
            Irp->IoStatus.Information = sizeof(KSPROPERTY_CAMERACONTROL_REGION_OF_INTEREST_S);
            Status = STATUS_SUCCESS;
        }
        else
        {
            Status = STATUS_INVALID_PARAMETER;
        }
    }

    return Status;
}