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C6748 LCDK - Video sync problem with facedetect demo

JumpStart
Intellectual 605 points

Hello E2E Community,

I am using the facedetect demo software and notice that the vertical video sync does not display correctly on the vga output.  This happens when I use a NTSC camera for input or using a VCR tape where I can stop the playback and restart the playback.  Subsequently, the captured image used by the algorithm is processing an image that has the bottom of the image wrapped on to the top of the image/screen. 

Has anyone encountered this and found a way to fix this issue?

Thanks,
JumpStart

  • 0
    TI__Intellectual 1585 points

    C6748 supports NTSC input image resolution of (720 X 488) for processing and  VGA display image resolution of (640 X 480) to output in Face detect demo.

    Please verify these resolution from your setup and revert back.

  • 0 in reply to Iyshwarya Gopalakrishnan
    Intellectual 605 points

    Hello Iyshwaryq,

    The image resolution of (720 x 488) and the VGA display resolution (640 x 480) is not the problem.  The face detect demo runs correctly when started up (power cycle) but when I lose video input (from VCR playback) that is when the problem occurs.

    The problem occurs especially when I use a VCR to playback a tape and when the tape ends and the VCR starts to rewind the tape, there is no playback video output from the VCR.  The VCR output displays the typical blue screen and that is when I notice that the C6748 VGA display shows the blue screen scrolling vertically down like it is not sync up correctly (vertical sync?).  When the tape is completely rewind, and I press the playback button on the VCR, the C6748 now sees the playback video but the output on the VGA show the image is vertically out of sync (there is a horizontal black band in middle of the image and the top of the image is below the black band and the bottom of the image is on the top of the band.  The black band does not scroll vertically but remains in that same position.  This black band seems to be the vertical sync portion of the image that is normally not displayed on the output.  The rest of the image looks good except that the image is verticall rolled

    ----------------------------------                                   ----------------------------------
    |         top of image            |                                   |                                            |
    |                                            |                                   |       bottom of image       |
    |                                            |                                   |bbbbbbbbbbbbbbbbbbb|  black band
    |                                            |                                   |          top of image           |
    |      bottom of image        |                                   |                                            |
    ----------------------------------                                   -----------------------------------

    Hope that clarifies what I am experiencing.

    Thanks,
    JumpStart

  • 0 in reply to JumpStart
    TI__Mastermind 20790 points

    Hi JumpStart,

    Can you try attached the facedetect_lcdk.c file.

    And add VPIF_SYNC in Predefined Symbols.

    Regards,

    Pubesh