如何检查是否正在使用我的DirectShow Renderer过滤器？ [英] How do I check if my DirectShow Renderer filter is being used?

问题描述

在我的DirectShow项目中，我创建了一个过滤器（从 CBaseVideoRenderer 派生）来渲染内存块。这在大多数情况下都很好，添加了过滤器

In my DirectShow project I create a filter (derived from CBaseVideoRenderer) to render to a block of memory. This works in most cases perfectly well, with me adding the filter

    mGraphBuilder->AddFilter(pInterfaceInfo, MemoryRendererName);

并依靠GraphBuilder做剩下的工作。但是在某些情况下，图形生成器和我的过滤器不能就一个通用格式达成一致，它会创建一个新的ActiveMovie窗口，绕过我的过滤器。

and relying on GraphBuilder to do the rest. However in some cases the graph builder and my filter cannot agree on a common format and it creates a new ActiveMovie window, bypassing my filter.

发生，所以我知道我的过滤器没有被使用，但不能解决如何。

I would like to detect when this occurs so that I know my filter is not being used, but cannot work out how.

我枚举图中的所有过滤器，寻找我的过滤器，使用以下方法：

I enumerate all filters in my graph, looking for my filter, using the following method:

（编辑：当我调用这个参数时，我传递了我的GraphBuilder对象作为pGraph参数）

( I pass my my GraphBuilder object as the pGraph parameter when I call this)

HRESULT MediaPlayer::CheckFilterGraphFor(IFilterGraph *pGraph, IBaseFilter* pFilterToLookFor)
{
    IEnumFilters *pEnum = NULL;
    IBaseFilter *pFilter;
    ULONG cFetched;

    HRESULT enumeratedFilterCount = 0;

    FILTER_INFO pRefFilterInfo;
    pFilterToLookFor->QueryFilterInfo(&pRefFilterInfo);

    HRESULT hr = pGraph->EnumFilters(&pEnum);
    if (SUCCEEDED(hr))
    {
        while(pEnum->Next(1, &pFilter, &cFetched) == S_OK)
        {
            enumeratedFilterCount--;

            FILTER_INFO FilterInfo;
            hr = pFilter->QueryFilterInfo(&FilterInfo);
            if (SUCCEEDED(hr))
            {   
                if(wcscmp(FilterInfo.achName, pRefFilterInfo.achName) == 0)
                {
                    pRefFilterInfo.pGraph->Release();
                    return S_OK;    
                }

                // The FILTER_INFO structure holds a pointer to the Filter Graph
                // Manager, with a reference count that must be released.
                if (FilterInfo.pGraph != NULL)
                {
                    FilterInfo.pGraph->Release();
                }
                pFilter->Release();

            }
        }

        pEnum->Release();
    }

    pRefFilterInfo.pGraph->Release();
    return enumeratedFilterCount;
}

但它不能按预期工作，

But it does not work as expected, as my filter is always found regardless of whether it is in use or not.

我如何知道当我的过滤器用作DirectShow图形的视频渲染器时，以及当它不是

How can I tell when my filter is in use as the video renderer for my DirectShow graph, and when it is not?

推荐答案

找到您的渲染器过滤器后，找到其输入引脚并检查是否已连接（IPin： ：ConnectedTo）

After finding your renderer filter, find its input pin and check if it's connected or not (IPin::ConnectedTo)

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