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Video vibrations/jello caused by aggressive stabilisation?

Discussion in 'Pro/Adv Discussion' started by allemtura, May 17, 2015.

  1. allemtura

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    I have a theory as to why we’re seeing lots of jello and vibrations in our Phantom 3 videos based on observations of the quad in windy conditions. Windy is the key difference here because I’ve noticed no issues on some days and others it’s been terrible.

    At first I thought it was due to unbalanced props as indeed my silver ones needed a lot of work/sanding, especially on the hub as that was quite out of balance. However despite now having perfectly balanced props, I was still seeing excessive vibrations in my videos (see this video as an example):



    I decided to closely examine the quad whilst it was hovering in windy conditions, and what is most striking is how aggressively it adjusts itself to maintain position. It makes lots of quick adjustments, and this in turn causes the camera to visibly vibrate quite excessively and wobble on its gimble. I will try and create a video showing this later (no wind at the moment).

    Update: From my post below, here is a video of the quad with a wobbly camera. You can see the normal quad vibrations in the legs, and the gimbal dampeners do a very good job to stop those from affecting the camera. However its the quick adjustments the quad makes to maintain position that causes the camera frame to wobble



    Ultimately I think this can be fixed via firmware so that the quad maintains its position with less abrupt adjustments, but at a loss off maintaining its position. I recall that my P2V+ used to float around more in windy conditions, and I think that is the difference between the two.

    Thoughts?
     
    #1 allemtura, May 17, 2015
    Last edited: May 17, 2015
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  2. RoyVa

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    Normally the vibration dampeners on the gimbal help prevent the jello. With the gimbal operating properly the quads movement should not really be noticeable to the point it jellos. But if it's jersey really fast I guess we could see that effect. How many other users are seeing this effect ?
     
  3. FlyMN

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    I am seeing some jello and jitters but it's wind and/or sunny days.

    I've balanced my props, changed props, tried different dampeners, but the best solution is to fly when weather / sun conditions are best.

    Yes, balanced props do matter. Reducing vibration does help, but even with a vibration-free video, high shutter speeds just don't look natural.

    A couple of points, in general the wind is stronger during midday when the sun's strength is the highest. Not always, but generally speaking. And when the sun is the strongest (brightest conditions), the higher the shutter speed will be...usually up over 1/1000 sec. or double that.

    Here's the things I would suggest for those who want top-notch filming with the P3 or other craft:

    1. Try to fly in the morning and late afternoon and rarely midday on sunny days. The "golden hour" as photographer's know is the best time to photograph/video. Winds should better too.

    2. Try to keep the shutter speed to 1/120 sec or lower. If conditions are too bright, use an ND filter.

    3. Don't fly in strong winds. (The P3 or any other aerial platform will struggle in strong winds and cannot stay locked in place anyway even if there was no jitter/jello effect. Not worth the effort in my opinion.)

    Just my 2-cents-worth.
     
    #3 FlyMN, May 17, 2015
    Last edited: May 17, 2015
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  4. Stan_in_KS

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    Many other threads on this subject. Most were fixed by 1) Removing white foam gimbal shipping stabilizer on the back of the gimbal. or many reported when they recorded in MP4 versus MOV format the jello appeared in MP4 and disappeared in MOV. If you removed the foam and recorded in MOV format, I'm out of wisdom.
     
  5. blade strike

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    Turn down your atti gain and give that a try. It will either help or not.
     
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  6. Fplvert

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    I saw on one simmilar thread, Mohan suggested using the black dampners from GoPro gimbal. Might be worth a try?
     
  7. blade strike

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    Guys at some point there is a limit at where you won't get stable footage.

    You can tune the gimbal for wind but then you will start to see micro vibration in a hover, from the harder dampeners.

    Imho, anything more than 10mph and expecting to get solid video is a pipe dream on this size of craft.
     
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  8. Buzz313th

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    Jello is not limited to drone footage.. It is also known as "Rolling Shutter Effect" in the video world. Get your shutterspeeds down to an acceptable time and you will entirely remove The "Rolling Shutter Effect".

    Whats acceptable depends on the shot.. A shutterspeed of less than or equal to twice the FPS will guarantee no Jello during any shot, including unstable flight.

    If you have stable flight and the objects in frame are not moving too fast, you can get away with shutterspeeds as high as 1/2000s at 60 fps, or 1/1000s at 30 fps..

    If your footage is just fooked.. you can use editing software to create motion blur as a bandaid. Or if you want your footage to look like Saving Private Ryan, just go with the high shutterspeed.

    As mentioned earlier in this thread.. To get your shutterspeed down..

    1. Shoot at the lowest locked ISO possible.
    2. Shoot in conditions with less light if you don't have ND's (Early morning, late afternoon, sunrise, sunset, magic hour, overcast.)
    3. Use ND's
     
  9. ianwood

    ianwood Taco Wrangler
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    The ND does not fix the vibration that causes jello. It only masks it.

    One of the most commonly overlooked ways to reduce jello is to slow down! The more aggressive you fly, the more likely you induce vibration. You don't need to fly very fast to get exceptional shots.

    Finally, gimbal dampening is a dark science. On the P2, there are hacks to improve the dampening. Some of those may apply to the P3. For example, replace stock drop screws with zip ties, use the black dampeners with ear plugs in them. A big improvement.

    Even more finally, I've never found any benefit in messing with gains for reducing vibration. But maybe the P3 is different in that respect.
     
  10. Buzz313th

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    That makes sense.. With the lower shutterspeed, the jello/Vibration gets swallowed up in a frame that's has motion blur... and a loss of a clear image.
     
  11. leekiya

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    Im with you on this one blade.
    An on another note i think a lot of jello problems people will be having will be down to what ever TV or computer they are playing the video back on. I did a flight the other morning before work in 1080/25 and on the computer at work i watched it back on there was bad jello when a building came into view after flying over fields, then on my computer at home not as bad. Since then i have watched that same video on different tvs and computers and devices i have at home. The same video on my 50" 720p older 100hz plasmas downstairs produced all most no jello at all, then playing back the video on my newer 1080p led tvs upstairs in our room (42") and my sons room (37") the jello was more noticeable on both by a long way, the much smaller 1080p tv in the kitchen (19") was the same story. Then i put the video onto my ipad and all jello was 100% gone. I don't know a great deal on the jello subject or video but thought i would post my findings as it may help others.
     
  12. DrChris

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    Blade, Can you explain more about the attitude gain parameter? I've read about the P2's but it seems that the P3 setting is different (with just one "attitude gain" parameter).

    Thanks!
    Chris
     
  13. blade strike

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    It will tone down external force responsiveness and responses from the pilot when turned down.

    The draw back is the craft won't feel as locked in.

    Remember there's always a plus and negative when tunning. The key is to find what works best for both the craft and the individual pilot.
     
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  14. allemtura

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    Hi All,

    What I’m hoping to do is try and resolve the excessive vibrations I’m seeing in my videos please, and to do this I’ve uploaded a number of videos to demonstrate the problem.

    Blade, good thought on adjusting the atti gain, I’ll give that a go. It seems to make sense because if I reduce this it should be slower when adjusting to maintain position. However where do I do this please? Is it that section in the app with the three graphs where the wavy line can be adjusted?

    I am sorry blade but this isn't true based on my own flying experience. Let me demonstrate why with the following video I took last year with my P2V+. As you can see from the trees it was very windy conditions, around twice as windy as the video I took today, yet the video is super smooth. There’s no vibrations or jello, and I know my props weren’t balanced at the time. Having had over 200 flights with my P2V+, I never had the jello problems that I’m seeing with my P3P.



    Compare it to this video from today and you can see from the trees how calm it is, yet the video has some terrible jello/vibrations in certain scenes. Key thing to note that it doesn’t happen all the time - would unbalanced props cause jello constantly? Also would a high frame rate / sunny day cause constant jello, or would you expect the result I’m seeing? (It's fairly smooth video till around 25 seconds, then the jello kicks in when panning sideways, and later on in the clip too. Best watch full screen to see the shakes)



    So I took some more video showing the quad in slow-mo to try and show what I’m referring to. From the video below you can see the normal quad vibrations in the legs, and the gimbal dampeners do a very good job to stop those from affecting the camera. However its the quick adjustments the quad makes to maintain position that causes the camera frame to wobble, as seen in the video. (again best watch in full screen)



    As it stands I really can’t take the same smooth quality videos that I used to do on my P2V+, so perhaps I have a faulty unit? I have fully balanced my props (willing to take a video to show how balanced they are), so other than adjusting the atti gain as mentioned by blade, can anyone suggest anything else? I’m still within 14 days of delivery and I’m seriously considering returning it as faulty and trying another one out…

    Buzz313th - so to compare with my P2V+, do you know if the shutter speeds were much slower on that camera compared to the P3P? Just wondering if that’s why I never had issues with it?

    Also as seen by the wobbly gimbal video, I don’t think changing the shutter speed will help here as there’s no getting around physical shaking. I will try a set of black dampeners as suggested though, and the atti gain to see what happens.

    Thanks everyone!
     
  15. allemtura

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    I'm curious to know if others could try hovering in front of you to see if the camera wobbles much please? I've watched plenty of videos in the shared video thread and none seem to be as bad as mine. Odd. :)