Mavic footage flickering
2872 11 2016-12-8
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andremercier
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Just got my Mavic a couple days ago, took it out to shoot a sunrise this morning and upon reviewing the footage found some really bad flickering in the yellow tones near the sun.
Has anyone seen anything like this?



It flickers like that intermittently throughout all of my shots. I shot it in D-Log, AWB, 4k 30fps.

2016-12-8
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Nees
lvl.4
Flight distance : 80991 ft
Belgium
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You are the 2nd one with this issues on the forum where I saw this. It occoured on black/dark levels, like the camera is boosting it and then dropping back to normal. I think it is a hardware defect. Prepare yourself for an RMA...
2016-12-8
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rnrnrn
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Flight distance : 430932 ft
Germany
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This is very dependent on your camera settings. Automatic white balance will do that for example. In case of such shots you need to go manual on this. @ Nees - hardware is just a sensor getting the light in. What you see on the screen is software. As far as I can tell there is no chance for this to be hardware related, so RMA wouldn't make sense in this case.
2016-12-8
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4wd
Second Officer
Flight distance : 545817 ft
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United Kingdom
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I'd want to see if it did it in manual white balance and manual exposure.
The auto setting in both will often create annoying jumps between steps.
2016-12-8
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flyingasd
lvl.3
Flight distance : 31089 ft
Italy
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select a non auto white balance and lock the AE (auto exposure).
2016-12-9
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fans6715505a
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I'm getting this type of result as well, though not quite as extreme. The problem seems to be in the red and the blue channels. It's all pretty noisy, but the red and blue channels are the worst. It looks to be a codec issue to me. If I had my guess, it's being caused by really bad bi-directional frame interpolation, leading to the i-frame encoding causing very large and noticeable changes in the hue/saturation levels, so every time you hit an i-frame (every 8 frames), the entire image suddenly changes red and blue levels. I'm trying to figure out how to correct this in Davinci Resolve right now, but not getting very far. I have the RGB channels split out, but a denoiser isn't very helpful, since it's actually the red and blue levels that are changing suddenly every eight frames. It would be nice if there was some sort of plugin that temporally interpolated the color channels. What would also be great is if DJI would release a firmware update that used a better recording codec, since this one obviously sucks. Disclaimer, all the above may be complete crap, but it's what it looks like to me. I'd welcome other input.

As a side note, using D-Log or any of the other modes that compress the luma and chroma levels only exacerbates the above, since the problem seems to be in the codec. Therefore, if you use a compressed saturation color setting on your camera  and then encode it, you have to oversaturate your image to decompress the chroma levels in post. This seems to greatly over-emphasize the color changes, making them much more noticeable in your final product. Also, in addition to the red/blue color changes, there is a high level of banding in the red/blue channels which really comes out in post if you greatly over-saturate your levels to decompress them.

2017-5-9
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Tuesday328
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Alright, I've done a full day of testing with the Mavic Pro in controlled conditions and my conclusion is that DJI is really playing some games with bandwidth on their codec. The big culprit for the flickering noise is in the red channel. It is present on YRGB, but red is the most noticeable with blue being second. I did confirm that I was correct in my post yesterday, anything you do to increase saturation in post really brings out the noise compression, thus the extreme example posted by the OP.

I ran my tests using Cinelike and Normal. I tested in 4K, 2.7K and 1080p at 24, 30 and 60fps. What I found is that DJI is really doing a lot of cheating with their bandwidth. It seems like the higher you crank your settings, worse the footage gets. 60fps is very visibly just 30fps doubled at half resolution. One only has to look at a still frame of 30fps next to a still frame of 60fps to see it. The best results I got where at 2.7K 24fps. 30fps was only slightly noiser than 24, so there was really almost no difference between the two. There is a marked difference between 4K and 2.7 in terms of noise. When I looked at the 2.7 footage, most of the i-frame stepping effect was gone. It is still present if you really look hard, but for the most part only normal chroma noise was visible. The macro blocking was also reduced in the chroma channels. Finally, as I hypothesised in my previous post, shooting at a more saturated setting and then desaturating in post greatly reduced the contrast in the chroma noise. There was a visible reduction in noticeable noise from 0,0,0 to 0,0,+1 to 0,0,+3.

In conclusion, I'm going to say D-Log should be right out. The contrast and saturation expansion that has to occur in post really blows out the compression noise and makes it very visible as evident in the OP's video.  Cinelike was very useable, but I will most likely be shooting Normal 0,0,+1 at 2.7K 24fps from now on.
2017-5-10
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Ex Machina
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United States
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Tuesday328 Posted at 2017-5-10 11:56
Alright, I've done a full day of testing with the Mavic Pro in controlled conditions and my conclusion is that DJI is really playing some games with bandwidth on their codec. The big culprit for the flickering noise is in the red channel. It is present on YRGB, but red is the most noticeable with blue being second. I did confirm that I was correct in my post yesterday, anything you do to increase saturation in post really brings out the noise compression, thus the extreme example posted by the OP.

I ran my tests using Cinelike and Normal. I tested in 4K, 2.7K and 1080p at 24, 30 and 60fps. What I found is that DJI is really doing a lot of cheating with their bandwidth. It seems like the higher you crank your settings, worse the footage gets. 60fps is very visibly just 30fps doubled at half resolution. One only has to look at a still frame of 30fps next to a still frame of 60fps to see it. The best results I got where at 2.7K 24fps. 30fps was only slightly noiser than 24, so there was really almost no difference between the two. There is a marked difference between 4K and 2.7 in terms of noise. When I looked at the 2.7 footage, most of the i-frame stepping effect was gone. It is still present if you really look hard, but for the most part only normal chroma noise was visible. The macro blocking was also reduced in the chroma channels. Finally, as I hypothesised in my previous post, shooting at a more saturated setting and then desaturating in post greatly reduced the contrast in the chroma noise. There was a visible reduction in noticeable noise from 0,0,0 to 0,0,+1 to 0,0,+3.

Interesting. I just found out that Normal actually has some saturation "enhancement" according to DJI, which might affect your findings. The same source said that TrueColor is what I would have expected Normal was, straight out of camera. Fwiw.
2017-5-10
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thehippoz
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Flight distance : 23 ft
United States
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Ex Machina Posted at 2017-5-10 12:31
Interesting. I just found out that Normal actually has some saturation "enhancement" according to DJI, which might affect your findings. The same source said that TrueColor is what I would have expected Normal was, straight out of camera. Fwiw.

That sounds about right. I know there is a bit of greens being enhanced in normal.
2017-5-10
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Tuesday328
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I have not messed with TrueColor at all. I was tempted to, but noted that while the color was a little less "enhanced," at least on the tablet, the contrasts seemed heavier. I did feel that Normal gave the most natural color tones in terms of RGB balance. Cinelike strips some of the red tones out of the image, which then give issues if you try to add them back in. Not a big deal if you're shooting trees or grass in good lighting. Shooting in Normal allows you to desat a bit in post too. If I were shooting the OP's sunset, I'd probably go with Normal since it yields cleaner red saturation.

All said and done, though I've been running more tests today and have come to the conclusion that the biggest culprit is the 4K. 2.7K yields much less compression flicker. After today, I feel like if I needed to get footage straight from the camera with no real grading, I would use Normal 0,0,0; however, for grading I did find that Normal was a pain in the butt. Once I got lift and gain set right, the gamma ranges were compressed to a small band that was about useless (at least in the test scene I was working with). In the future, I'll be most likely going with 2.7K, 24fps, Cinelike +1,-1,0. This was the setting that yielded the best balance for me between grading flexibility, noise/flicker, and LUT friendliness. If I get the opportunity, I'll run through some tests with TrueColor to see how it compares.
2017-5-11
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kinglevel
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Tuesday328 Posted at 2017-5-11 13:01
I have not messed with TrueColor at all. I was tempted to, but noted that while the color was a little less "enhanced," at least on the tablet, the contrasts seemed heavier. I did feel that Normal gave the most natural color tones in terms of RGB balance. Cinelike strips some of the red tones out of the image, which then give issues if you try to add them back in. Not a big deal if you're shooting trees or grass in good lighting. Shooting in Normal allows you to desat a bit in post too. If I were shooting the OP's sunset, I'd probably go with Normal since it yields cleaner red saturation.

All said and done, though I've been running more tests today and have come to the conclusion that the biggest culprit is the 4K. 2.7K yields much less compression flicker. After today, I feel like if I needed to get footage straight from the camera with no real grading, I would use Normal 0,0,0; however, for grading I did find that Normal was a pain in the butt. Once I got lift and gain set right, the gamma ranges were compressed to a small band that was about useless (at least in the test scene I was working with). In the future, I'll be most likely going with 2.7K, 24fps, Cinelike +1,-1,0. This was the setting that yielded the best balance for me between grading flexibility, noise/flicker, and LUT friendliness. If I get the opportunity, I'll run through some tests with TrueColor to see how it compares.



Got the Mavic a couple of days ago, my first drone, so far i am SUPER IMPRESSED. One of the coolest quality product i have ever bought.

But, the exposure flickering is a little bit of disappointment... You can see the same in my clip.
Its so close to perfection.. I really hope DJI will fix this.
2017-5-18
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Tuesday328
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kinglevel Posted at 2017-5-18 06:59
https://www.youtube.com/watch?v=MPSvdIMJgAY

Got the Mavic a couple of days ago, my first drone, so far i am SUPER IMPRESSED. One of the coolest quality product i have ever bought.

Kinglevel, what settings did you use?
2017-5-23
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