Filter Connection Issue - c++

Question

When I try to connect my custom written filter to an avi mux filter in graphedt it automaticaly adds a Microsoft DTV-DVD Audio Decoder in between, which isnt need because i proces video streams.
How does graphedt decide to do that and how can i prevent that?
How do two filters decide if they are compatible?
Here is the header file of my output pin:
#pragma once
#include <streams.h>
#include "MyFilter.h"
class MCMyOutputPin : public CBaseOutputPin
{
private:
// parent
CBaseFilter *mux;
IUnknown *position;
public:
MCMyOutputPin(MyFilter* filter, HRESULT *phr, LPCWSTR pName);
virtual ~MCMyOutputPin();
STDMETHODIMP NonDelegatingQueryInterface(REFIID riid, void **ppv);
// overriden
virtual HRESULT CheckMediaType(const CMediaType *pmt);
virtual HRESULT SetMediaType(const CMediaType *pmt);
virtual HRESULT CompleteConnect(IPin *pReceivePin);
virtual HRESULT BreakConnect();
virtual HRESULT GetMediaType(int i, CMediaType *pmt);
virtual HRESULT DecideBufferSize(IMemAllocator *pAlloc, ALLOCATOR_PROPERTIES *pProps);
virtual HRESULT Deliver(IMediaSample* sample);
virtual HRESULT AgreeMediaType(IPin* recievePin, const CMediaType *pmt);
// qual prop
STDMETHODIMP Notify(IBaseFilter *pSender, Quality q);
CMediaType &CurrentMediaType() { return m_mt; }
};
And here its implementation:
#include "CMyOutPutPin.h"
#include <fstream>
MCMyOutputPin::MCMyOutputPin(MyFilter* parent, HRESULT *phr, LPCWSTR pName) : CBaseOutputPin(NAME("MyOutPutPin"), parent, &parent->m_lock_filter, phr, pName)
{
}
MCMyOutputPin::~MCMyOutputPin()
{
}
STDMETHODIMP MCMyOutputPin::NonDelegatingQueryInterface(REFIID riid, void **ppv)
{
return CBaseOutputPin::NonDelegatingQueryInterface(riid, ppv);
}
HRESULT MCMyOutputPin::CheckMediaType(const CMediaType *pmt)
{
return S_OK;
}
HRESULT MCMyOutputPin::SetMediaType(const CMediaType *pmt)
{
return CBaseOutputPin::SetMediaType(pmt);
}
HRESULT MCMyOutputPin::CompleteConnect(IPin *pReceivePin)
{
return CBaseOutputPin::CompleteConnect(pReceivePin);
}
HRESULT MCMyOutputPin::BreakConnect()
{
return CBaseOutputPin::BreakConnect();
}
HRESULT MCMyOutputPin::GetMediaType(int i, CMediaType *pmt)
{
return CBaseOutputPin::GetMediaType(i, pmt);
}
HRESULT MCMyOutputPin::DecideBufferSize(IMemAllocator *pAlloc, ALLOCATOR_PROPERTIES *pProps)
{
ALLOCATOR_PROPERTIES act;
HRESULT hr;
// by default we do something like this...
pProps->cbAlign = 1;
pProps->cBuffers = 1;
pProps->cbBuffer = this->CurrentMediaType().lSampleSize;
pProps->cbPrefix = 0;
hr = pAlloc->SetProperties(pProps, &act);
if (FAILED(hr)) return hr;
// make sure the allocator is OK with it.
if ((pProps->cBuffers > act.cBuffers) ||
(pProps->cbBuffer > act.cbBuffer) ||
(pProps->cbAlign > act.cbAlign))
return E_FAIL;
return NOERROR;
}
STDMETHODIMP MCMyOutputPin::Notify(IBaseFilter *pSender, Quality q)
{
// right now we don't do anything ...
return NOERROR;
}
HRESULT MCMyOutputPin::Deliver(IMediaSample* sample)
{
std::ofstream outfile;
outfile.open("C:\\TEMP\\yc1.log", std::ios_base::app);
outfile << "receiving data on outputpin" << std::endl;
outfile.close();
m_pInputPin->Receive(sample);
return CBaseOutputPin::Deliver(sample);
//Forward to filter
}
HRESULT MCMyOutputPin::AgreeMediaType(IPin * pin, const CMediaType* pmt)
{
return S_OK;
}

Answer 1

It happens first of all because pins cannot connect directly. So basically preventing means you would not be able to connect pins, and you would have an error instead.
Additional filter insertion is called Intelligent Connect
Compatibility is ability to connect, to succeeded in IPin::Connect and IPin::ReceiveConnection method