where is key frame ?

i  use the intel media sdk to encode video .

when  i get the encoded frame i want to know what frame it is .

sts = m_VideoSession.SyncOperation(syncp,6000) ;
MSDK_CHECK_RESULT(sts,MFX_ERR_NONE,sts) ;
nLenOut = m_fxBS.DataLength ;
if (MFX_FRAMETYPE_I==m_fxBS.FrameType)
{
bKeyFrame = TRUE ;
}
else
{
bKeyFrame = FALSE ;
}
WriteBitStream(&m_fxBS,pBuffOut) ;

up  is my code  i am confused about  the  m_fxBS.FrameType

its value  is 193 when i encoded the first frame ,this must be a key frame ,but the sdk do not define  any value  193 as the frame type ,

sometime it return 66 the same .

and  very little it return 4 that means a B_frame

i was confused about this

is anybody  who can give me some suggest?

very appreciate it

thank you very much  in advanced