Code to print all filter categories supported in DirectShow

EnumerateFilterCategories.cpp

// -----------------------------------------------------------------
// Enumerate all objects in this category, printing the name
// -----------------------------------------------------------------
void enum_cat(REFGUID cat)
{
  HRESULT hr;
  ICreateDevEnum *pSysDevEnum = NULL;
  IEnumMoniker *pEnum = NULL;
  IMoniker *pMoniker = NULL;
  VARIANT var;

  hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, 
    IID_ICreateDevEnum, (void**)&pSysDevEnum);  
  if (FAILED(hr))
    return;

  hr = pSysDevEnum->CreateClassEnumerator(cat, &pEnum, 0);
  if (hr == S_OK && pEnum)
  {
    while (S_OK == pEnum->Next(1, &pMoniker, NULL))
    {
      if ( !pMoniker ) continue;
      IPropertyBag *pPropBag = NULL;
      pMoniker->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pPropBag);
      if ( !pPropBag ) continue;
      VariantInit(&var);
      hr = pPropBag->Read(L"FriendlyName", &var, 0);
      if (SUCCEEDED(hr))
        printf("\t%S\n", var.bstrVal);
      VariantClear(&var);
      if (pPropBag) pPropBag->Release();
      if (pMoniker) pMoniker->Release();
    }
  }
  if ( pSysDevEnum ) pSysDevEnum->Release();
  if ( pEnum ) pEnum->Release();
}

// -----------------------------------------------------------------
// Enumerate all categories in the array
// -----------------------------------------------------------------
void enum_categories()
{
#define catentry(n) {#n,n}
  struct cat { const char* catname; GUID g; };
  cat cats[] = {
    catentry(CLSID_VideoInputDeviceCategory),
    catentry(CLSID_LegacyAmFilterCategory),
    catentry(CLSID_VideoCompressorCategory),
    catentry(CLSID_AudioCompressorCategory),
    catentry(CLSID_AudioInputDeviceCategory),
    catentry(CLSID_AudioRendererCategory),
    catentry(CLSID_MidiRendererCategory),
    catentry(CLSID_TransmitCategory),
    catentry(CLSID_DeviceControlCategory),
    catentry(CLSID_ActiveMovieCategories),
    catentry(CLSID_DVDHWDecodersCategory),
    catentry(CLSID_MediaEncoderCategory),
    catentry(CLSID_MediaMultiplexerCategory),
  };
  
  if ( SUCCEEDED(CoInitializeEx(NULL, COINIT_MULTITHREADED)) )
  {
    for (int i = 0; i < ARRAYSIZE(cats); ++i)
    {
      printf("*** %s\n", cats[i].catname);
      enum_cat(cats[i].g);
    }

    CoUninitialize();
  }
#undef catentry
}