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Frontal Leds affecting the video - A2s (Solved: video compression problem)

V.Delduque

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I saw this weird flicker in the shadows in this footage and I think the frontal leds are reflecting off the propelers (they're dark, but kinda reflective too). You can see it better from the waveform.


Has anyone found a way to avoid this? Is there a "night shooting mode" somewhere in the menu?

Thanks!
 
Do you have a strobe on the A2s?

The front LED's should turn OFF when shooting video or when taking a picture. I don't think the rear LED's would interfere with the camera.

Not sure what's blinking in the wave form.

Sometimes when the sun shines through the props, they will create a choppy shadow that can be picked up by the camera.

Perhaps that's the anomaly. 🤔
 
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Hi! Thanks for replying :)

No strobes.
Waveform: you can see the shadows popping up at a constant rate (1 quick flick /sec). Try this video:
 
Another wild guess.. a strobe marker on one the buildings for aircraft?

I don't see anything in the video but the waveform image seems to be picking something up.
 
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Youtube's compression shouldn't allow you to see, but it's very clear in the waveform and in the footage itself to me :(

I had the same problem flying over an open area too.

I did a test filmming a white wall so the camera could pick a green reflection from the rear leds. I could see that everytime the rear leds turned on or off (in the waveform it's easy to see the green levels popping up) I was abble to see that blinking thing too. Turn on: blink. Turn off: blink.

9 years working with cinema cameras and I can't figure this out 😂
 
I figured the problem!

Some cameras can record every frame in the video without compression or a constant one, in which every frame hold the same compression or no compression at all. Cheaper or basic cameras use something like Long GOP: for every X group of compressed frames, there's one key frame containing full information. That blink we were seeing every X amount of time is the keyframe, which holds more information than the other frames inbetween them: noise included. Thank blink is literally more information showing in the waveform and the shadows are more "affected" because of the noise.

There's nothing we can do unless DJI release All-Intra compression, but I don't think this drone can process it.

Thanks for your help :)
 
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I had the same problem on my M2P. In my case, I was forcing the exposure way down in order to blacken the foreground objects. Not sure if setting such expose really caused the problem, but I turned off the front lights and still had some response in time with the rear lights. I was shooting in 4k, 30fps, HLG transfer function. Here is the observation using the video scopes...

To correct it, I simply placed a color mask in the areas affected and turned down the exposure. The video I was producing that used this blacken foreground effect was this one...
 
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I had the same problem on my M2P. In my case, I was forcing the exposure way down in order to blacken the foreground objects. Not sure if setting such expose really caused the problem, but I turned off the front lights and still had some response in time with the rear lights. I was shooting in 4k, 30fps, HLG transfer function. Here is the observation using the video scopes...

To correct it, I simply placed a color mask in the areas affected and turned down the exposure. The video I was producing that used this blacken foreground effect was this one...
Nice shot!

Yeah, mine was kinda underexposed indeed.. I didn't wanted to clip too much of the sky.

I've tested the compression theory with my mirrorles by setting it to long gop instead of all intra and got the same effect (less, but still). It's been a while since the last time I saw this type of compression.
 
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