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

CVI distortion

hi,

I'm experiencing distortion in my VIP path where I'm mixing two video streams:

TPG (800x600p RGB) -> MIXER_DIN_0

CVI (640x480p RGB) -> FRAMEBUFFER -> MIXER_DIN_1

The VIP chain is using a 50MHz system clock.

The MIXER outputs 800x600p RGB 3 colorplanes(colorbars) in parallel @60Hz using a 40MHz clock.

The CVI is clocking the 640X480 video stream inn using a 25.175MHz clock. The FRAMEBUFFER is setup for frame dropping/repetition. I'm pretty sure the 640x480 stream is correct prior to the CVI as I have clocked it out to a screen. However, when I provide the 640x480 stream to the CVI I'm getting distortion in the 640x480 overlay of the 800x600 video output. Can anyone provide som pointers here ? If this is timing related, how can it be fixed ?

Saber890

1 Reply

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

    It seems I managed to figure this one out.

    The Framebuffer read/write masters were accessing the same DDR2 SDRAM memory locations as an deinterlacer was using.

    This was causing the strange patterns in the output video. I changed the memory location for the FrameBuffer and now the output distortion is gone.

    Regards,

    Saber890