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ADV7182 creates dark line at bottom with NTSC input when ACE is ON

Hello,

I am facing an issue with ADV7182 chip in NTSC input format where I can see the dark line at the bottom when ACE feature is ON.

This dark line is clearly visible in blue color in free-run mode. The same is visible even in actual NTSC blue color data.

This dark line issue at bottom is seen only with NTSC format when ACE feature is ON.

And the dark line at bottom is not observed with NTSC format when ACE feature is OFF.

I could not see any dependencies in datasheet regarding ACE, Please provide the solution for this issue.

Note: ACE means Adaptive Contrast Enhancement.

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  • Hi Suresh,

    Could you please describe your system. Are you using an ADV7182 evaluation board or are do you have the ADV7182 in a system. If it is in a system would you mind telling me what is processing the BT656 output from the ADV7182.

    Would you mind sharing a picture a picture of the black line that occurs on the output from the ADV7182?

    Could you try toggling the BT656-4 bit (User Map, register 0x04 bit [7]). Setting this bit to 1 causes the ADV7182 to output video with the ITU-R BT.656-4 timing instead of the standard ITU-R BT.656-3 timing.

    If the receiver is expecting ITU-R BT.656-4 and ITU-R BT.656-3 is being output from the ADV7182 then this can result in black horizontal lines at the top of bottom of the screen.

    Regards,

    Robert Hinchy

    Applications Engineer,

    Digital Video Products Group,

    Analog Deivces Inc.

Reply
  • Hi Suresh,

    Could you please describe your system. Are you using an ADV7182 evaluation board or are do you have the ADV7182 in a system. If it is in a system would you mind telling me what is processing the BT656 output from the ADV7182.

    Would you mind sharing a picture a picture of the black line that occurs on the output from the ADV7182?

    Could you try toggling the BT656-4 bit (User Map, register 0x04 bit [7]). Setting this bit to 1 causes the ADV7182 to output video with the ITU-R BT.656-4 timing instead of the standard ITU-R BT.656-3 timing.

    If the receiver is expecting ITU-R BT.656-4 and ITU-R BT.656-3 is being output from the ADV7182 then this can result in black horizontal lines at the top of bottom of the screen.

    Regards,

    Robert Hinchy

    Applications Engineer,

    Digital Video Products Group,

    Analog Deivces Inc.

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