>I use the following Parameters in the evmdm642_vcapparms.c file
>
>VPORTCAP_Params.fldOp = VPORT_FLDOP_FRAME
>SAA7115_ConfParams.inmode = SAA7115_MODE_NTSC720
>SAA7115_ConfParams.outemode = SAA7115_MODE_CIF
>
>I detected that capture frame buffer,both the iFrm.cb1 and iFrm.cr1 has
a
>size of 50688 (176 x 288). 
>
>What should I do to downsample the capture frame to 4:2:0 , CIF standard
>(chroma 176 x144) and non-interlace?
>
>If I use the following method will i get the CIF standard.
>1) Drop the even lines ( get 4:2:0 )
>2) Average out every pair of vertical lines (get 176x144)
>
>Is my method correct? 
>
>Hope someone can clear my doubts. Thanks
>
>

Both 1 & 2 above will get you a chroma frame with size 176x144 with
different degrees perceived image of quality. Since the original data was
in 4:2:2 format, the downsampled chroma frames essentially simulate a
4:2:0 color subsampling scheme. 

I believe DM642 EVM video port has an option for hardware resampling of
captured 4:2:2 frames to 4:2:0. So check if you can use set and use this
option with the video driver. That'll save you a lot of cycles. 




		
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I use the following Parameters in the evmdm642_vcapparms.c file

VPORTCAP_Params.fldOp = VPORT_FLDOP_FRAME
SAA7115_ConfParams.inmode = SAA7115_MODE_NTSC720
SAA7115_ConfParams.outemode = SAA7115_MODE_CIF

I detected that capture frame buffer,both the iFrm.cb1 and iFrm.cr1 has a
size of 50688 (176 x 288). 

What should I do to downsample the capture frame to 4:2:0 , CIF standard
(chroma 176 x144) and non-interlace?

If I use the following method will i get the CIF standard.
1) Drop the even lines ( get 4:2:0 )
2) Average out every pair of vertical lines (get 176x144)

Is my method correct? 

Hope someone can clear my doubts. Thanks