Just how much Moire is taken out from the upload transcoding process compared to the original clip.

This weekend at the Denver Aquarium I found really good examples of  Moiré Patterns when shooting DSLR video on my Canon T2i 550D.

Check out the pants on the juggler closes to me! Wow, that’s a Moire! (say with Italian accent)

I brought down the sharpness in camera to 0 and then increased it in post. What I wanted to know was how much reduction in Moire is there from the original clip after it has been transcoded by video sharing sites like Vimeo and YouTube.

After comparing the original to the transcoded version it appears that Vimeo’s transcoding did reduce it just a bit more, not a ton but it definitely helped.

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15 comments

  • I shoot a lot of tennis matches, and publish to the web. After a year of doing this, a player wanted a DVD, so when I created the DVD, the net was completely engulfed with moire. It was not watchable. You might not realize you have a moire problem until you publish a DVD.

  • The difference between the two is significant — more so than I expected. Also, you were clearly shooting at 720, and that’s worse than 1080 relative to moire/aliasing.

    “Sharpness” doesn’t actually change the resolution of images — rather, it’s an image contrast tool — meaning it increases the contrast of edges. So, an image shot at minimum “sharpness” has the exact same image detail and resolution as an image shot with maximum “sharpness,” the only difference is the image processing.

    There’s a lot of misinformation out there and there are people who will argue the above point — but I’m right.

    The other issue is that the “sharpness” setting, when turned up, also enhances the sharpness of noise. Meaning, the higher your sharpness setting — the more noise you’re going to see.

    So, if you understand the above, then the solution is to turn the “sharpness” all the way down in camera, and do sharpening in post. Sharpening in post is an entirely different discussion — some techniques and algorithms are better than others, etc. Vast discussion in a sentence — better programs do better jobs.

  • @Andrew another aspect to consider is rendering time, if you want to pump something out fast, I would go with sharpened image inside the camera rather than in post because post sharpening adds a lot of time to the rendering.

  • (I’m not seeing a reply to comment button)

    TO JOHN STEWART

    There are further complications because you’re down-scaling from HD 720 (or 1080) to DVD resolution, and depending on your post production software, that can introduce all sorts of issues that could severely enhance an existing problem.

  • @Dave Rendering time entirely relates to your software and system capabilities.

    The key issue is that it’s easier to sharpen something in post than it is to try to clean up noise and moire/aliasing.

    Also, sharpening in post allows you complete creative control. Un-sharpening in post (soft focus filters or adjustment layers, etc.) introduces other complications.

    Finally, if you’re using professional post production software — you’ll generally end up with better results than with in-camera processing.

    Bottom line — do whatever works for you. I’m simply sharing from my experience.

  • No matter what rounds you give to the subject, Moire can only be soften sacrificing sharpness and
    as Andrew says this doesn’t fix Moire . IS LIKE A STAINED PHOTO.
    GREAT NEWS : The new technology is in this DSLR Sony camera

    http://www.bhphotovideo.com/c/product/731596-REG/Sony_SLT_A55V_Alpha_DSLR_SLT_A55_Digital_Camera.html

    Footage I have seen doesn’t show Moire at all, Don’t worry about follow focus, focusing or zooming
    is all right there , Works like a video camera, the actual concept is gone . I BET Canon will release
    an EVF DSLR Camera , to compete to this new translucent mirror technology
    EVF good bye Moire

  • Hi, i stumbled onto your site thru google alerts and I must say you have a bundle of info here for people starting out and a great site to match ive honestly bookmarked the site to return again and I see the ozine layer is gonna be more mucked up now with that fire. Ive never thought about the transcoding side of things and ive even got my own video site makeityourself.me.uk running on a phpmotion script I wonder how bad that is.

  • Hey Dave,

    Probably stating the obvious here but moire really becomes an issue when you shoot at 60fps…. right? I don’t see how 1080 or 720 makes a difference.I haven’t had any issues shooting at 24/25fps only at higher frame rates. I wonder if shutter speed plays a part in the moire factor? KEEP UP THE GREAT WORK!

    Oh and I think Moire should be pronounced with a French accent..ha.ha

  • @Roberto,

    The transition from 1080 to 720 will make the moire more noticeable, because the sensor is being subsampled to an even greater extent. Using only 720 lines of the T2i’s giant sensor means there’s more information (even more than @ 1080) that the camera has to “make up” to output that video.

    If Dave had shot this at 640 (standard definition), you would see the moire become even more pronounced.

  • Cool thanks Nick, but what about the frame rate? Why at 24/25fps does it not become an issue?

    Here’s something else I need closure on, why is there no difference in file size shooting 720 or 1080?

  • Actually, i’m missing something here, check out page 132 of the T2i manual:

    1920×1080 (30/25/24fps) 16GB card = 49min rec time

    1280×720 (60/50fps) 16GB card = 49min rec time

    So does that mean you should be able to shoot for twice as long at 720 (24fps)?

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