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[ADV7480] Sample settings for Automatic mode

Category: Datasheet/Specs

Hi,

We had a question from Customer.
We would like to confirm the sample settings that use "7.7 COLOR SPACE CONVERSION MATRIX" in Automatic mode.

Problem phenomenon:
When inputting after converting hdmi_colorspace: 0000b (RGB_LIMITED) to csc_coeff_sel_rb: 0101b (RGB to YPbPr 601), the hue cannot be converted correctly and the hue is output with a shifted hue.
  HDMI(RGB_LIMITED) → ADV7480(RGB_LIMITED→YPbPr 601) → SoC (UYVY input)

The image received from a Windows PC is shifted by 44 pixels to the left, and the right edge is black.
  44 pixel left shift (1920×1080)
  32 pixel left shift (1280×768)

(1)Are there any registers that specify left and right offset values?

(2)Can you think of any other reasons why the images may be distorted?

We have asked Customer to confirm the values of the relevant registers, and we believe these settings are correct.

Best regards.

Parents
  • Hi,

    Could you please try with the reference script which is available at http://www.analog.com/media/en/engineering-tools/design-tools/ADV7481ES3C-VER.3.6c.txt?

    You may not get such a pixel shift from the default reference configuration.

    The position of the signal can be controlled by configuring the below register.

    Hue adjustment is done on YCrCb data stream; It can be done in CP-core by:

    • Enabling video adjustmnets (VID_ADJ_EN, CP-core, 0x3E[7] )
    • Setting hue to desired value (CP_HUE, CP-core, 0x3D[7:0] )

    Thanks,
    Dharani S

  • Thank you for the information.

    Is this hue adjustment setting also required for Automatic CSC settings?
    Currently both are set to 0x00.

    Hue adjustment is done on YCrCb data stream; It can be done in CP-core by:
    • Enabling video adjustmnets (VID_ADJ_EN, CP-core, 0x3E[7] )
    • Setting hue to desired value (CP_HUE, CP-core, 0x3D[7:0] )

    When inputting after converting hdmi_colorspace: 0000b (RGB_LIMITED) to csc_coeff_sel_rb: 0101b (RGB to YPbPr 601), the hue cannot be converted correctly and the hue is output with a shifted hue.
    In the customer confirmation, the blue color has become reddish-purple.
      HDMI(RGB_LIMITED) → ADV7480(RGB_LIMITED→YPbPr601) → SoC (UYVY input)

    Can you think of any other reasons why the images may be distorted?

    Best regards.

  • Hi,

    Have you observed the same behaviour in our evaluation board?

    It seems like the issue is with scaling and please let us know if you have changed the aspect ratio to see for improvement.

    Note: The csc_scale[1:0] bits allow the user to implement conversion formulae in which the coefficients exceed the standard range of [-4095/4096 .. 4095/4096]. The overall range of the CSC is [0..1] for unipolar signals (for example, Y, R, G, and B) and [-0.5..+0.5] for bipolar signals (for example, Pr and Pb).

    To support larger coefficients, the csc_scale[1:0] function should be used. Determine the setting for csc_scale[1:0] and adjust coefficients, if necessary.
    For further details Refer Page187 in ADV748x_Hardware Manual_Rev: (+) ADV7481 output image is stretched - Q&A - Video - EngineerZone (analog.com)

     

    Perhaps the following thread might be useful for you:

    Adjusting Hue in Video decoders and HDMI receivers

    And also have you checked both free run/internal pattern format

    Thanks,
    Dharani S

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