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KSPROPERTY_CAMERACONTROL_EXTENDED_SECURE_MODE

KSPROPERTY_CAMERACONTROL_EXTENDED_SECURE_MODE is mainly used by the OS to check whether the camera driver supports secure authentication before enabling and using it. This control is not meant to be used by regular applications.

Overview

When enabled, the camera driver issues secure kernel frame buffers as opposed to buffers in user-mode system memory. Secure kernel frame buffers are useful in scenarios such as biometrics authentication where the frame content authenticity needs to remain unaltered by any user-mode driver components. This secure buffer can be queried from the COM interface IMFSecureBuffer

// mfobject.h
interface IMFSecureBuffer : IUnknown
{ 
    /// Get a GUID identifier for the secure buffer 
    HRESULT GetIdentifier(GUID *pGuidIdentifier); 
};

This interface can be queried from an existing IMFMediaBuffer:

ComPtr<IMFSample> spSample; 
DWORD dwTotalBufferLength = 0; 
DWORD dwBufferCount = 0;
DWORD dwStreamIndex = 0 //Read first stream for samples 
DWORD dwActualStreamIndex = 0;
DWORD dwStreamFlags = 0; 
LONGLONG llTimeStamp = 0ll
ComPtr<IMFSourceReader> spSourceReader;

// assuming the IMFSourceReader object spSourceReader is correctly provisioned from the camera
//...

// retrieve an IMFSample from the IMFSourceReader
VERIFY_SUCCEEDED(spSourceReader->ReadSample(dwStreamIndex, 0, &dwActualStreamIndex, &dwStreamFlags,  &llTimeStamp, spSample.GetAddressOf()));
if (nullptr != spSample.Get())
{
    VERIFY_SUCCEEDED(spSample->GetBufferCount(&dwBufferCount));
    for (DWORD dwIndex = 0; dwIndex < dwBufferCount; dwIndex++)
    {
        ComPtr<IMFMediaBuffer> spMediaBuffer; 
        ComPtr<IMFSecureBuffer> spSecureBuffer;
        if (SUCCEEDED(spMediaBuffer->QueryInterface(IID_PPV_ARGS(&spSecureBuffer)))) 
        {
            // this is a secure buffer
            GUID guidIdentifier = GUID_NULL; 
            WCHAR strGuid[64];

            // Get a GUID identifier for the secure buffer.
            // Use this identifier to access the buffer in secure kernel.
            VERIFY_SUCCEEDED(spSecureBuffer->GetIdentifier(&guidIdentifier)); 
        } 
    }
}

Usage summary table

Scope Control Type
Version 1 Pin Synchronous

The following are flags that can be placed in the KSCAMERA_EXTENDEDPROP_HEADER.Flags field to enable or disable secure mode on the driver.

#define KSCAMERA_EXTENDEDPROP_SECUREMODE_DISABLED               0x0000000000000001 
#define KSCAMERA_EXTENDEDPROP_SECUREMODE_ENABLED                0x0000000000000002

If the driver supports this control, it must support both KSCAMERA_EXTENDEDPROP_SECUREMODE_DISABLED and KSCAMERA_EXTENDEDPROP_SECUREMODE_ENABLED.

This is a synchronous control. Must be set before starting the stream.

The following table describes the flag capabilities.

Flag Description
KSCAMERA_EXTENDEDPROP_SECUREMODE_DISABLED This is a mandatory capability
KSCAMERA_EXTENDEDPROP_SECUREMODE_ENABLED This is a mandatory capability

The following table contains the descriptions and requirements for the KSCAMERA_EXTENDEDPROP_HEADER structure fields when using the control.

Member Description
Version Must be 1.
PinId Must be advertised on only one pin on the filter. The pin must be type PINNAME_VIDEO_CAPTURE or PINNAME_VIDEO_PREVIEW
Size Must be sizeof(KSCAMERA_EXTENDEDPROP_HEADER)+ sizeof(KSCAMERA_EXTENDEDPROP_VALUE).
Result Indicates the error results of the last SET operation. If no SET operation takes place, Result must be 0.
Capability Must be a bitwise OR of the supported KSCAMERA_EXTENDEDPROP_SECUREMODE_XXX flags defined earlier.
Flags This field is read/write. The value must be any one of the KSCAMERA_EXTENDEDPROP_SECUREMODE_XXX flags defined earlier. These flags are mutually exclusive and can't be set in any bitwise OR combination.

Requirements

Header: Ksmedia.h

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