MPEG4 Decoder Filter Problem

MPEG4 Decoder Filter:
----------------------
within MPEG4 Decoder Filter,we will allow only keyframe for the first time by Checking the following :
if( m_bFirstFrame)
{
if ( (pSourceBuffer[0] == (unsigned char) 0x0) && (pSourceBuffer[1] == (unsigned char) 0x0) && (pSourceBuffer[2] == (unsigned char) 0x1) &&
((pSourceBuffer[3] == (unsigned char) 0xB0) // VOS Start Code
((pSourceBuffer[3] ==(unsigned char) 0xB6) && // VOL with KeyFrame
( (pSourceBuffer[4] & 0xC0)== 0x00) )
(pSourceBuffer[3] == (unsigned char) 0x20)
) )
{
m_bFirstFrame = false;
}
else {
//Wait For KeyFrame
if (NOERROR == pSource->GetTime(&TimeStart, &TimeEnd))
{ pDest->SetTime(&TimeStart, &TimeEnd);
}
return NOERROR;
}
}

if we got the First frame, then we will send the data to the MPEG4 Decoder DLL APIs whatever we got from the RTP source Filter.

Note :
------------
MPEG4 Decoder DLL APIs support only frame by frame decompression.
That means at atime we can pass only one frame to the MPEG4 decoder DLL Apis. otherwise MPEG4 Decoder will fails.