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  1. Gregos
    Join Date
    Feb 2019
    Location
    London
    Search Comp PM
    Greetings to all, I am really happy to join this forum. If this is a wrong section please forgive me as this is my first post.

    I have recently been to USA and bought a Gopro Hero 7 to film some nice places, and what I did not know is that the hyper smooth stabilization (or whatever its called), does actually ruin the video in low light conditions ( I havent had a chance to check the video on a big screen till i came back home to UK).

    I am really frustrated because it ruined most of my holiday videos. Please see the linked video to see what I mean...

    https://youtu.be/4L1Um9Z5cAg?t=20 - starts at 0:20s

    (best to see in 4K)

    Is there any way to smooth or somehow fix the unwanted blur shaky parts? I plan to buy Vegas pro 16 soon if that helps...

    Any advice would be really appreciated!

    Thanks, and best regards, Greg.
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  2. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    I would not describe the video you posted to be filmed in 'low light'.

    What you seem to have is several different light sources and the exposure is struggling to determine which one is prime. Hence that 'flashing' on the neon.

    No NLE, such as Vegas, can fix that. Maybe someone with the knowledge can suggest some avisynth script but maybe you will have to put that down to experience. Could you not have tested the camera in similar conditions such as Picadilly Circus before you travelled ?
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  3. Several thoughts.

    A GoPro is probably the wrong camera for filming vacations. It has a fixed lens (no zoom), almost no adjustments, lousy optics, etc. Don't get me wrong, I like the camera (I have the Sony version) and it is a brilliant camera for taking actions shots.

    The video you posted has been motion stabilized. I just Googled "hypersmooth" (which is what it is called) and basically the camera performs software stabilization in the camera, much as you would do in post production with Mercalli, Twixtor, Deshaker, etc.

    I have written extensively about motion stabilization and what you are seeing is a classic artifact of what happens when motion is stabilized in post after the the video was recorded with a shutter speed of 1/30 or 1/25 of a second. These are the normal shutter speeds for NTSC and PAL cameras filming at 30 or 25 fps progressive.

    Without this extra stabilization, when the camera jerks around during hand-held filming, you see the unwanted motion, just like we've all seen with amateur hand-held video all of our lives. What you don't notice when watching these shaky videos, because of the motion, is that each frame taken during the time the camera is moving a lot is blurred, just like a still photo would be blurred at a low shutter speed if you didn't hold the camera steady. But here's the thing: you don't see that blur both because your eye expects to see a blur when things are moving fast, and because the shakiness doesn't let your eye dwell on the blur. However, when the motion is removed by the post-capture stabilization, your eye can easily see the blur and you get the effect you see in your video where the focus seems to pop in and out, much like what happens when autofocus is trying to hunt for its focus point. (BTW, the usual stabilization done in the camera moves the image via a mirror or by shifting pixels and therefore there is no blur).

    What to do?

    Unfortunately you can't do a thing to fix the video you've already taken. Having said that, for blurs that only last one frame, you could mark each spot where the blur occurs and interpolate a new frame at that point. I did this for a film transfer where the film camera, decades ago, had a bad sprocket advance, and the film had not pulled all the way through the camera. On those frames that weren't registered properly, I marked them, and then used my version of "FillDrops()", an old AVISynth script that uses motion interpolation to replace the marked frames. Here is a before/after:

    https://www.youtube.com/watch?v=uzMFodrGHDs

    I've posted the AVISynth scripts over in doom9.org and could provide a link if you are up for this effort. It is tedious, but as you'll see in that clip, the result is near perfect (I wish I had posted the section where the truck pulls away because it is far more impressive to see the jumps removed and while the truck is moving -- the interpolation did a perfect job of creating a new frame with the truck in exactly the correct position).

    Finally, if you want to avoid this problem in the future, you must manually increase the shutter speed on your camera. In a video camera this is done electronically and you set it via a menu or with a button on the side of the camera. If you get the shutter up to 1/125 or 1/250 or 1/500, then when the camera moves, the frame will be captured without the blur, and then when it is stabilized after the fact -- whether in the camera or with professional motion stabilization software -- you will not get these blurs. Unfortunately, in low light, you may not have the option of using higher shutter speeds unless you have a very professional camera that lets you increase the gain (i.e., higher ISO) and tradeoff grain for shutter speed. I don't think the GoPro has such an adjustment, and almost certainly doesn't let you manually set a lot of these parameters because, as I said earlier, this is the wrong camera to use for this kind of filming. Use it instead for mounting on the hood of your car, or on your helmet, or the handlebars of your bike, or on your surfboard, but don't use it to take video of Las Vegas, your home town parades, or your daughter's wedding. (Well, actually I DID use a GoPro to take my daughter's wedding, but it was one of four cameras I used, and it was secreted away in a space behind the wedding party, looking back at the audience. No one could see it, and its incredibly wide field of view was able to capture the entire wedding party in the foreground, as well as the entire audience.)
    Last edited by johnmeyer; 15th Feb 2019 at 10:51. Reason: typos
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