mfxFrameSurface1 Pitch size

How and where does pitch get set? I see that  

Encoder has a line 
MSDK_MEMCPY_VAR(m_pVppSurfaces[i].Info, &(m_mfxVppParams.mfx.FrameInfo), sizeof(mfxFrameInfo));

This line  sets the info struct of  mfxFrameSurface1
But where does the surface.data.pitch get set of mfxFrameSurface1
Does it automatically mults width by 8 bytes and since we alight the width with MSDK_ALIGN16 ?

Thanks