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Re: Camera preview, thin lines in the frames






Shun-Yu Chang wrote:
Hello, list:
    I am new to v4l2.  I am working on integrating a usb camera device on
the beagleboard(Omap3530 dev board).
    Now I met a camera preview issue that is there are thin lines coming out
in the frames.
    I still have no idea how to describe this exactly. It's like the images
shows here,
    http://0xlab.org/~jeremy/camera_preview.html

I have two guesses. One is the jpeg compression ,or is it jpeg? Try saving in raw RGB or Ycbcr format and viewing with imagemagick.

Does this happen in live preview? Maybe write data from camera directly to screen to see if happening there.

The second would be the FIFO (hadn't worked with omap before) levels of the data lines to the processor in the kernel.

Look at the system processor (top) usage to see how much cpu% is being used. USB has high overhead.

Regards,
Ryan

    I modified capture.c sample to save the frames to picture files.  So in
my guess,  the problem is not in userspace. And this is not happen on my
laptop with the usb camera.
    Could anybody give me a clue ?  Any one would be thankful.


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