BRAW SDK: how to use IBlackmagicRawConstants

The docs tell us to use IBlackmagicRawConstants to get ranges for the various parameters, but how do we actually get an IBlackmagicRawConstants object? I see it in the header, but don't see a way to get one out of IBlackmagicRawFactory or IBlackmagicRawClip or something.

Basically something like this:

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HRESULT result = S_OK;
IBlackmagicRawConstants* constants;
result = codec->QueryInterface(IID_IBlackmagicRawConstants, (void**)&constants);


codec is of type IBlackmagicRaw* here.

And then you can query the constants object for ranges and stuff. This is a piece I use for reading ranges and value lists from attributes in my player project:

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 HRESULT BrawDecoder2::updateClipProcessingAttribute(BlackmagicRawClipProcessingAttribute sdkAttribute, BrawProcessingAttribute* attribute)
{
    VARIANT valueMin;
    VARIANT valueMax;
    HRESULT result = S_OK;
    BOOL isReadOnly;

    BSTR cameraType;
    clip->GetCameraType(&cameraType);

    // First try to get attribute range
    result = constants->GetClipProcessingAttributeRange(cameraType, sdkAttribute, &valueMin, &valueMax, &isReadOnly);
    if (result == S_OK)
    {
        attribute->updateValueRange(valueMin, valueMax, isReadOnly);
    }

    // If range query fails, attribute uses value list, so retrieve that
    if (result == E_INVALIDARG)
    {
        std::vector<VARIANT> variantList;
        UINT variantListLen;

        result = constants->GetClipProcessingAttributeList(cameraType, sdkAttribute, nullptr, &variantListLen, &isReadOnly);
        if (result == S_OK)
        {
            variantList.resize(variantListLen);
            result = constants->GetClipProcessingAttributeList(cameraType, sdkAttribute, &variantList[0], &variantListLen, &isReadOnly);
            if (result == S_OK)
                attribute->updateValueList(&variantList[0], variantListLen, isReadOnly);
        }
    }

    // Finally retrieve actual values
    processingAttrs->GetClipAttribute(sdkAttribute, &attribute->value);

    return S_OK;
}


Yep, that did it. Thanks, Hendrik!