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AM4376: VPFE support format

Kanae
Guru 10225 points

Part Number: AM4376
Other Parts Discussed in Thread: AM4372,

Hi Support Team,

My customer is considering using the AM4372 VPFE to capture image data drawn by an external IC.
Their system requirements are as follows.

*Part number in title; AM4376 is typo, AM4372 is correct.


-Image size to be captured is 768*1024@60Hz (60MHz) or 600*800@56Hz (36MHz).

-The external drawing IC draws on the monitor based on RGB signals,
 but since the VPFE side of the AM437x does not support this,
 it also draws Digital YCbCr Mode 8-bit pictures separately.

-The Vsync/Hsync/DE output by the drawing IC is used.

-Disable the field signal and use the Progressive Mode.

Q1. They would like to convert a 24-bit RGB signal to Digital YCbCr Mode 8-bit as follows.
Can you tell me the input format for Digital YCbCr Mode 8-bit?

They would like to convert to Digital YCbCr Mode 8-bit to match the AM4372 VPFE format,
but the Digital YCbCr Mode 8-bit input format is not described in detail in the AM437x TRM.

Q2. In the VPBE manual for the TMS320DM643x DMP, the format is described as YCC8 below.

https://www.tij.co.jp/lit/ug/spru952a/spru952a.pdf

If they consider the format to be the same as the above chart, it is as follows.
Since the luminance component is thinned out to 1/2 and the color difference component to 1/4,
smoothing processing between pixels seems to be necessary.
Is there any problem with input according to the following time chart?

if you have unclear items in the post, please let me know.

Best regards,
Kanae

  • 0
    Guru 10225 points


    Hi Support Team,

    Regarding the above post, my customer is requesting confirmation of a date
    when he can get a response.
    Could you please let me know the schedule you can respond to?

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Expert 3340 points

    Hi Kanae,

    I am looking into this and will provide an answer by tomorrow. Thank you for your patience. 

    Best,

    Andrei

  • 0
    TI__Mastermind 43875 points

    Kanae,

    YCbCr mode only decimates the color channels, not the luma. The clock rate is 2x the pixel rate in 8 bit mode so that one luma and 1/2 chroma sample is transferred every 2 clocks.

    BR,

    Steve

  • 0
    TI__Mastermind 43875 points

    Kanae,

    YCbCr mode only decimates the color channels, not the luma. The clock rate is 2x the pixel rate in 8 bit mode so that one luma and 1/2 chroma sample is transferred every 2 clocks.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Guru 10225 points


    Hi Steve,

    Thank you for your reply.
    Do you have any documents that contain the information you have provided?
    Please let us know the website of the document and the specific part of the document.

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 43875 points

    Kanae,

    I don't have anything specific for the AM4376 since I don't actually work in that group, but there are lots of guides etc... in the internet relating to different standard digital video formats and sampling modes.

    e.g. https://en.wikipedia.org/wiki/Chroma_subsampling

    I would search terms like "digital video chroma sub sampling", "digital video formats" etc... for more details.

    The AM devices conform to the appropriate digital video standards so searches for things like "itu656", "bt656" etc might also help understand the data stream formats.

    Kind regards,

    Steve

  • 0 in reply to Steve Clynes
    Guru 10225 points

    Hi Steve,

    Thank you for your quick reply.

    As my customer is using AM4372, I need to check how to set up the system with AM4372.

    As you have informed me,
    "The AM devices conform to the appropriate digital video standards so searches for things like
    "itu656", "bt656" etc might also help understand the data stream formats."
    if this is the case, can you please confirm with your AM437x representative
    that there is no specific information in the AM4372 TRM etc. and that
    it is OK to refer to the guide relating to different standard digital video formats and sampling modes?

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Expert 3340 points

    Hi Kanae,

    To my knowledge that is the case, you should be able to follow standard industry guides for video formats and sampling modes. 

    Best,

    Andrei

    - Sitara MPU Apps

  • 0 in reply to Andrei Aldea
    Guru 10225 points


    Hi Andrei,

    Thank you for your reply.
    I will share your comment with our customers.
    Please continue to support us if I receive any additional enquiries from my customers.

    Best regards,
    Kanae