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5951 Discussions

VIP color conversion result ?

Altera_Forum
Honored Contributor II
768 Views

hi,  

 

I'w put togheter a VIP chain inorder to try out color space conversion : 

 

Tpg (720x576p YCrCb 4:2:2 (2 cp's in parallel)) ->  

Clipper (640x480p YCrCb 4:2:2 (2 cp's in parallel)) -> 

ChromaResampler (640x480p YCrCb 4:4:4 (3 cp's in parallel)) -> 

ColorSpaceConv. (640x480p RGB 4:4:4 (3 cp's in parallel)) -> 

ClockedVideoOut 

 

The VIP system uses a 66.5MHz clock. 

The color space converter uses the "CbCrY:SDTV to Computer B'G'R" color mode conversion. 

 

I'm able to clock the video out (displaying color bars) to screen @60Hz. 

 

However, when I compare the color conversion to a second VIP chain : 

 

TPG (640x480p RGB 4:4:4 (3 cp's in parallel)) -> 

ClockedVideoOut 

 

not using color conversion, there is a clear difference in the colors being displayed.  

 

The second VIP chain colorbars are displayed much moore clearly than the first chain, where as the first chain seems to have alot of RED in all the colorbars. Is it supposed to be like this, should'nt the color conversion provide just as clear color as the second chain ? 

 

 

 

Saber890
0 Kudos
2 Replies
Altera_Forum
Honored Contributor II
77 Views

bad colors in CSC conversion probably indicates improper fixed point coefficients, your screen shot backs this up 

 

you'll need at least 1 integer bit on the left side, and turn on signed coefficients and probably add a bit on the right
Altera_Forum
Honored Contributor II
77 Views

hi 

 

thank you for responding.  

 

Your tip certainly did help, the colors are much clearer now. 

 

 

Best regards 

 

Saber890
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