Filter Graph Fails to Recognize Custom Filter

[uday]

Dear Team,

I am having two source filters A and B. A has one output pin and B
has one input and one output pins.

The output of B connects to default MP3 decoder.

In the Graph Edit tool, When I insert both A and B filters manually,
rendering A output is successful but if I select only filter A and
select render output pin, the filter graph does not recognizes B
filter and gives error.

The error is no intermediate filter is found to render the pin. Here
are further details:

A::GetMediaType(const CMediaType *pmt)
{
pmt->SetType(&MEDIATYPE_Audio1);
pmt->ResetFormatBuffer();
}

B::CheckMediaType(const CMediaType *pmt)
{
if(pmt->majortype == MEDIATYPE_Audio1)
{
return S_OK;
}
return E_POINTER;
}

Can somebody point to the missing things.

Regards.