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davidp60953449
davidp60953449
Known Participant
October 9, 2017
Question

Vertical line anti-aliasing problem

  • October 9, 2017
  • 1 reply
  • 1670 views

I've read a number of posts about similar problems, but none that I've seen so far has solved this for me. In the clip below, you see a camera track on a grid created in AI. The vertical lines, particularly right in the center, are strobing. I've added a blur to them to the extent I can, changed the frame rate, sampling, etc. Nothing helps. The grid is 1 pixel, and I see from some advice that thickening them may help. But I'm at the end of this project, and changing that thickness would be a big headache. So I'd like avoid that. This particular clips is in H.264. Any suggestions?

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    1 reply

    Dave_LaRonde
    Dave_LaRonde
    Inspiring
    October 9, 2017

    Sorry to write this, but there's not much you can do except to widen the lines.  It's never a good idea to make 1-pixel-wide lines for reasons that are now painfully obvious to you.

    davidp60953449
    davidp60953449Author
    Known Participant
    October 9, 2017

    Hmmm. Maybe AI should have a pop-up when you choose 1 px lines, "Are you sure???"

    R
    Community Expert
    Rick GerardCommunity Expert
    Community Expert
    October 10, 2017

    To avoid aliasing that is painfully obvious horizontal and vertical lines need to be more than one pixel wide and perfectly aligned with the pixel grid. That's just a fact when you convert vectors to pixels.

    You also have problems with motion when the movement is not precisely a whole number of pixels per frame. Add to that stroboscopic effects that happen when movement is in or out of sync with frame rate.

    Throw compression artifacts that are more pronounced when you have thin lines and very contrasting colors because all MPEG compression compresses chroma in blocks of at least 4 pixels.

    My suggestion, add a bit of film grain or noise and speed up your move. That's the only thing I can think of that will perfect the movement. BTW, if the video is not shown at 100% scale the problems caused by thin lines will be worse.

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