ADV7625 RGB 4:4:4 Color Space Issue

I started this question with my original post: ADV7627 RGB 4:4:4 Color Space Issue 

Colorspace continues to plague my system and I am looking for some guidance. I have spent a considerable amount of time looking at the AVIAPI routines but there are some concepts that aren't quite clear.

Q1:  Does the switch automatically recognize the colorspace then do whatever is necessary to send out the colorspace in the same format?

Q2:  Sometimes the image does not look correct on the output display (sync). Is this because the display does not support the colorspace and encoding format of the source device?

Q3:  By default, are the AVI InfoFrames passed directly and automatically from the source device to the sync (assuming no errors in the packet checksum)?

Q4:  If the source device obtains the color / format capabilities from the sync via EDID, why would we ever have issues regarding color processing? 

I appreciate the discussion on this issue.

Phil

  • 0
    •  Analog Employees 
    on Nov 16, 2016 11:14 AM

    Hi,

    Do you have one of our evaluation board?

    Our ADV7625 evaluation board can be configured using software driver or through script.

    Are you configuring the board through software driver or through script?

    If you use the software driver, please provide the details of the Software driver version that you have been using it.

    If you use the script, please mention the specific script that you are using it from ADV7625 design support files.

    Here's the support page:

    AdvantivTm EVAL-ADV7625-SMZ Video Evaluation Board

    You can see the software package source code download link there.

    Best Regards,

    Jeyasudha.M

  • Jeyasudha,

    I am trying to understand the concept and the behavior of the ADV7625 and this is not clear in the HW or Register guides/manuals. Having the EVAL board will not help me understand what is happening and the behavior between the ADV7625, the source device, and the sync.

    If I can understand the relationships between these devices then I can better understand the AVIAPI and understand my role in the development of my own ADV7625 product.

    Thank you.

    Phil

  • Are you able to respond to any of these questions? I am trying to get a better understanding of these chips. I have experience with other ADI chips (ADV7627, ADV7850, etc.) but I like to have a conceptual idea how these chips behave when trying to write our own code. The ADIAPI by itself won't work for us without significant modification and knowing what is important to us and what is not helps simplify our coding/testing/validation.

    Thank you, Jeyasudha.

  • 0
    •  Analog Employees 
    on Nov 22, 2016 10:19 AM

    Hi,

    Q1:  Does the switch automatically recognize the colorspace then do whatever is necessary to send out the colorspace in the same format?

    A1:You can refer 6.29 section for the input color space and 9.10 section for the output color space from hardware manual which is at https://ez.analog.com/docs/DOC-10766

    Q2:  Sometimes the image does not look correct on the output display (sync). Is this because the display does not support the colorspace and encoding format of the source device?

    A2:Refer this thread What happens when I get the color space info incorrect?

    Q3:  By default, are the AVI InfoFrames passed directly and automatically from the source device to the sync (assuming no errors in the packet checksum)?

    A3.If you use mux-mode, then AVI infoframes are passed from the receiver to the transmitter.Otherwise the software driver will handle this. In your case your software have to monitor the AVI infoframes for color space, bit depth, audio type, etc. and configure the transmitter appropriately.

    Also When check sum error bit  is set, then  our application will discard the AVI Info frame data..

    Q4:  If the source device obtains the color / format capabilities from the sync via EDID, why would we ever have issues regarding color processing? 

    A4:Second question answer would be applicable for this also.

    Best Regards,

    Jeyasudha.M

  • Great info, Jeyasudha. Most appreciated.

    Follow up question:  When does one require the use of the CSC (color space converter)? Is it required when the source device sends the image with a colorspace not supported by the colorspace defined within the CEA 861 extension block of the EDID?

    Finest regards,

    Phil