Video - Shimmering / Aliasing on edges

Budy · Dec 31, 2019

Hi all. I've just acquired the M2Z and this is my second flight with it. This is a small scene of the video I've taken. It's in 1080p60. I haven't touched any other video settings. I notice quite an annoying amount of shimmering/aliasing particularly on the edges and roof of the buildings as you can see from the video. Is there some settings I could set to eliminate or at least minimize this effect?
Just a note, I'm playing this video on my 1080p LED screen, so there shoudn't be any scaling involve here

new2mavic · Dec 31, 2019

Can see any on my iphone 11 pro

THE CYBORG · Dec 31, 2019

Do you have your shutter speed at twice the frame rate ?

Budy · Dec 31, 2019

It's not really noticeable in a small screen such as phone. However I can see them clearly on PC (1080p, same res as the video) and my 4K TV.

I've checked my settings for video and it is set to auto, which I believe does not allow the shutter speed to be changed. The style is set to standard, all 0s. What settings should I try to eliminate this effect in that particular scene?

DanMan32 · Jan 1, 2020

Are you referring to prop shadow? With sun at the right angle, the props chop up the sun causing a pulsed shadow. That combined with the shutter speed and frame rate and you get shadow bars.

You can reduce the effect of prop shadow by getting the shutter speed down so that it's around 2x frame rate. You would ideally accomplish that with appropriate ND filter. With Pro you can also adjust aperture though that has its limits.

ff22 · Jan 1, 2020

The question may be about moire affect? Where certain patterns or repeating lines shimmer?

Budy · Jan 1, 2020

Hi All, thanks for the replies.

I'm not sure if this can be called moire. It's like staircase effect on the edges. If you've played a 3D game with low or no antialiasing you will notice this effect. I try to zoom in on the problematic area below. You can see that the edge of the roof which is almost horizontal is kinda "wavy" and not smooth. It's particularly problematic if the angle is like this. You can compare it to other edges of the roof with larger angle do not exhibit this effect. Once I turn and thus view them in a different angle, the effect disappear. I hope it's clear enough, I'm sorry if I make you guys guessing what I meant earlier

new2mavic · Jan 1, 2020

This is due to straight lines changing to stepped lines after sampling by the image sensor. The closer the lines to being horizontal, the fewer the number of steps hence more visible. This effect can be reduced by blurring the image appropriately. Antialiasing in 3D games is basically blurring the image or increasing the resolution of graphic rendering. Blurring is the purpose of antialiasing filters in front of digital camera image sensors. You can introduce blurring in post processing or choosing a slower shutter speed ( in shutter-prioirty mode, not auto ) Alternatively you can increase the fineness of image sampleing by shooting in 4K.

Budy · Jan 1, 2020

Thanks, I'll try to shoot in 4K and/or playing with the shutter speed. I try to avoid doing post if possible. Maybe I should tweak the sharpness setting also? Was hoping there's some camera settings I can adjust which is effective to minimize this effect

What kinda surprise me however, I don't recall seeing this artifact when shooting with the P3P 1080p60, so I'm a bit concerned with the result I get here with the M2Z. It looks great indeed, but with this kind of scene, it's just so irritating to watch

new2mavic · Jan 1, 2020

I just played with my Mavic 2 Pro and found that the aliasing problem in your video was due to the frame rate instead of anything else :

1080p 30 fps shutter speed 1/50 sec

1080p 60 fps shutter speed 1/50 sec

It seems that the sampling is a lot coarser in the 60fps video. May be the video is interlaced ?

Budy · Jan 1, 2020

Thanks for testing this. The 60fps one looks pretty bad and there's a clear difference in quality compared to the 30fps one. I guess the only solution is to avoid 60fps? A shame really. I can't find evidence that it's interlaced, ffmpeg seems to confirm also that it's progressive.

Sleepy · Jan 5, 2020

Was that video posted from your phone or is it actually from the drone itself? Looks like a lot of noise in it to be from the drone.

Budy · Jan 6, 2020

That video is from the drone itself. I've since tried recording in 4K30 and later converting to 1080p60, much better. I wish I don't have to do post but the native 1080p60 recording is just flawed

Blakjac · Jan 23, 2020

I had this problem as well, but after rendering the video in post it went away. I shoot 4k at 24 fps.

Budy · Jan 24, 2020

Glad I'm not the only one experiencing this effect. Yup 4K30 is much better. 1080p60 is also great unless with a scene like the above.

kawartha · Jan 24, 2020

In camera settings set sharpness to -1 or lower to reduce moire when you have a lot of parallel lines in your shot. Also 30 fps helps as well. Shutter at 2X framerate is preferred but the first 2 help the most. You can also blur in post but that gets messy.