How to create a directshow video capture filter?

After creating a capture graph builder, how can I directly query a video capture filter? The example I have only got an enumerator for all devices thru monkiers... is it the only path I need to use?
Thanks
Jack

Well, though you have to write the code by yourself, I can provide some code snippets.
1.Pin requirements for capture filters.

Code:

---

// Set: Cannot set any properties.
HRESULT CMyCapturePin::Set(REFGUID guidPropSet, DWORD dwID,
    void *pInstanceData, DWORD cbInstanceData, void *pPropData,
    DWORD cbPropData)
{
    return E_NOTIMPL;
}

// Get: Return the pin category (our only property).
HRESULT CMyCapturePin::Get(
    REFGUID guidPropSet,  // Which property set.
    DWORD dwPropID,        // Which property in that set.
    void *pInstanceData,  // Instance data (ignore).
    DWORD cbInstanceData,  // Size of the instance data (ignore).
    void *pPropData,      // Buffer to receive the property data.
    DWORD cbPropData,      // Size of the buffer.
    DWORD *pcbReturned    // Return the size of the property.
)
{
    if (guidPropSet != AMPROPSETID_Pin)
        return E_PROP_SET_UNSUPPORTED;
    if (dwPropID != AMPROPERTY_PIN_CATEGORY)
        return E_PROP_ID_UNSUPPORTED;
    if (pPropData == NULL && pcbReturned == NULL)
        return E_POINTER;
    if (pcbReturned)
        *pcbReturned = sizeof(GUID);
    if (pPropData == NULL)  // Caller just wants to know the size.
        return S_OK;
    if (cbPropData < sizeof(GUID)) // The buffer is too small.
        return E_UNEXPECTED;
    *(GUID *)pPropData = PIN_CATEGORY_CAPTURE;
    return S_OK;
}

// QuerySupported: Query whether the pin supports the specified property.
HRESULT CMyCapturePin::QuerySupported(REFGUID guidPropSet, DWORD dwPropID,
    DWORD *pTypeSupport)
{
    if (guidPropSet != AMPROPSETID_Pin)
        return E_PROP_SET_UNSUPPORTED;
    if (dwPropID != AMPROPERTY_PIN_CATEGORY)
        return E_PROP_ID_UNSUPPORTED;
    if (pTypeSupport)
        // We support getting this property, but not setting it.
        *pTypeSupport = KSPROPERTY_SUPPORT_GET;
    return S_OK;
}

---

2.Implementing a preview pin (that’s completely optional)

Code:

---

// Override CBasePin::CheckMediaType.
CCapturePin::CheckMediaType(CMediaType *pmt)
{
    if (m_pMyPreviewPin->IsConnected())
    {
        // The preview pin is already connected, so query the pin it is
        // connected to. If the other pin rejects it, so do we.
        hr = m_pMyPreviewPin->GetConnected()->QueryAccept(pmt);
        if (hr != S_OK)
        {
            // The preview pin cannot reconnect with this media type.
            return E_INVALIDARG;
        }
        // The preview pin will reconnect when SetMediaType is called.
    }
    // Decide whether the capture pin accepts the format.
    BOOL fAcceptThisType = ...  // (Not shown.)
    return (fAcceptThisType? S_OK : E_FAIL);
}

// Override CBasePin::SetMediaType.
CCapturePin::SetMediaType(CMediaType *pmt);
{
    if (m_pMyPreviewPin->IsConnected())
    {
        // The preview pin is already connected, so it must reconnect.
        if (m_pMyPreviewPin->GetConnected()->QueryAccept(pmt) == S_OK)
        {
            // The downstream pin will accept the new type, so it's safe
            // to reconnect.
            m_pFilter->m_pGraph->Reconnect(m_pMyPreviewPin);
        }
        else
        {
            return VFW_E_INVALIDMEDIATYPE;
        }
    }
    // Now do anything that the capture pin needs to set the type.
    hr = MyInternalSetMediaType(pmt);

    // And finally, call the base-class method.
    return CBasePin::SetMediaType(pmt);
}

CPreviewPin::CheckMediaType(CMediaType *pmt)
{
    if (m_pMyCapturePin->IsConnected())
    {
      // The preview pin must connect with the same type.
      CMediaType cmt = m_pMyCapturePin->m_mt;
      return (*pmt == cmt ? S_OK : VFW_E_INVALIDMEDIATYPE);
    }
    // Decide whether the preview pin accepts the format. You can use your
    // knowledge of which types the capture pin will accept. Regardless,
    // when the capture pin connects, the preview pin will reconnect.
    return (fAcceptThisType? S_OK : E_FAIL);
}

---

3. Producing data in capture filter (that’s completely your code, just a small snippet for help)

Code:

---

CMyVidcapFilter::GetState(DWORD dw, FILTER_STATE *pState)
{
    CheckPointer(pState, E_POINTER);
    *pState = m_State;
    if (m_State == State_Paused)
    {
        return VFW_S_CANT_CUE;
    }
    else
    {
        return S_OK;
    }
}

---

If you like my answer, do rate my post.:D:D