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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

VIP color conversion result ?

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

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    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's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    hi

    thank you for responding.

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

    Best regards

    Saber890