NF modules output data size is too small.

Hi.

I try video format conversion YUV422(1920x1080) to YUV420 use NF modules.

NF modules input data size is 4147200 (=1920*2*1080).
I expect NF modules output data size is 3110400 (=1920*1080*3/2).
But, output data size is 3041280 (pBufferOut->nFilledLen).

Is there any mistake in my setup parameters for NF module? 

setup is

----------- IL_ClientSetNfParams() -------------
------ OMX_PARAM_BUFFER_MEMORYTYPE ----
Nf Input Port
 nSize          = 16  
 nVersion       = 0x101
 nPortIndex     = 0  
 eBufMemoryType = 1 [OMX_BUFFER_MEMORY_DEFAULT    ]
------ end of OMX_PARAM_BUFFER_MEMORYTYPE ----
------ OMX_PARAM_BUFFER_MEMORYTYPE ----
Nf Output Port
 nSize          = 16  
 nVersion       = 0x101
 nPortIndex     = 16  
 eBufMemoryType = 1 [OMX_BUFFER_MEMORY_DEFAULT    ]
------ end of OMX_PARAM_BUFFER_MEMORYTYPE ----
Buffer Size computed: 4147200
set input port params (width = 1920, height = 1080)
------ OMX_PARAM_PORTDEFINITIONTYPE ----
Nf Input Port
 nSize              = 96      
 nVersion           = 0x20101    
 nPortIndex         = 0      
 eDir               = 0(OMX_DirInput)  
 nBufferCountActual = 6      
 nBufferCountMin    = 1      
 nBufferSize        = 4147200      
 bEnabled           = 0      
 bPopulated         = 0      
 eDomain            = 1[OMX_PortDomainVideo]  
  format.video.cMIMEType             = (null)   
  format.video.pNativeRender         = (nil)   
  format.video.nFrameWidth           = 1920   
  format.video.nFrameHeight          = 1080   
  format.video.nStride               = 3840   
  format.video.nSliceHeight          = 0   
  format.video.nBitrate              = 0   
  format.video.xFramerate            = 30   
  format.video.bFlagErrorConcealment = 0   
  format.video.eCompressionFormat    = 0x0 
  format.video.eColorFormat          = 0x19 
  format.video.pNativeWindow         = (nil)   
 bBuffersContiguous = 0      
 nBufferAlignment   = 128      
------ end of OMX_PARAM_PORTDEFINITIONTYPE ----
Buffer Size computed: 3110400
set input port params (width = 1920, height = 1080)
------ OMX_PARAM_PORTDEFINITIONTYPE ----
Nf Output Port
 nSize              = 96      
 nVersion           = 0x20101    
 nPortIndex         = 16      
 eDir               = 1(OMX_DirOutput)  
 nBufferCountActual = 6      
 nBufferCountMin    = 4      
 nBufferSize        = 3110400      
 bEnabled           = 0      
 bPopulated         = 0      
 eDomain            = 1[OMX_PortDomainVideo]  
  format.video.cMIMEType             = (null)   
  format.video.pNativeRender         = (nil)   
  format.video.nFrameWidth           = 1920   
  format.video.nFrameHeight          = 1080   
  format.video.nStride               = 1920   
  format.video.nSliceHeight          = 0   
  format.video.nBitrate              = 0   
  format.video.xFramerate            = 30   
  format.video.bFlagErrorConcealment = 0   
  format.video.eCompressionFormat    = 0x0 
  format.video.eColorFormat          = 0x15 
  format.video.pNativeWindow         = (nil)   
 bBuffersContiguous = 0      
 nBufferAlignment   = 128      
------ end of OMX_PARAM_PORTDEFINITIONTYPE ----
set number of channels
set input resolution
------ OMX_CONFIG_VIDCHANNEL_RESOLUTION ----
Set Input resolution
 nSize         = 60  
 nVersion      = 0x101
 nPortIndex    = 0  
 eDir          = 0(OMX_DirInput)
 nChId         = 0  
 Frm0Width     = 1920  
 Frm0Height    = 1080  
 Frm0Pitch     = 3840  
 Frm1Width     = 0  
 Frm1Height    = 0  
 Frm1Pitch     = 0  
 FrmStartX     = 0  
 FrmStartY     = 0  
 FrmCropWidth  = 1920  
 FrmCropHeight = 1080  
------ end of OMX_CONFIG_VIDCHANNEL_RESOLUTION ----
set output resolution
------ OMX_CONFIG_VIDCHANNEL_RESOLUTION ----
Set Output resolution
 nSize         = 60  
 nVersion      = 0x101
 nPortIndex    = 0  
 eDir          = 1(OMX_DirOutput)
 nChId         = 0  
 Frm0Width     = 1920  
 Frm0Height    = 1080  
 Frm0Pitch     = 1920  
 Frm1Width     = 0  
 Frm1Height    = 0  
 Frm1Pitch     = 0  
 FrmStartX     = 0  
 FrmStartY     = 0  
 FrmCropWidth  = 1920  
 FrmCropHeight = 1080  
------ end of OMX_CONFIG_VIDCHANNEL_RESOLUTION ----
------ OMX_CONFIG_ALG_ENABLE ----
Nf setup
 nSize          = 20  
 nVersion       = 0x101
 nPortIndex     = 0  
 nChId          = 0  
 bAlgBypass     = 0  
------ end of OMX_CONFIG_ALG_ENABLE ----
------ OMX_CONFIG_SUBSAMPLING_FACTOR ----
Nf setup
 nSize              = 16  
 nVersion           = 0x101
 nPortIndex         = 0  
 nSubSamplingFactor = 1  
------ end of OMX_CONFIG_SUBSAMPLING_FACTOR ----
----------- IL_ClientSetNfParams() done -------------

Regards.
miki shinji