Hi all,

Trying this post again cause I changed my user name and I can't find the first one.

Anyway, I have a new Mavic Mini and there is a strange pulsing in the video that I shot today. It's using the EV function and locked exposure. It's like the video slightly darkens once per second throughout the whole thing. Is this a defect with the drone?

I checked another video I did a few days ago on full auto mode. The pulsing is there but much more subtle.

Here's a sample from today:

https://drive.google.com/open?id=1LWfh7xRotG22Y_zmmhLyIXVrQdyCPzci

Does it always happen or just where there is high contract between the snow and the trees?

I see it in the foliage. That's definitely something weird. Thanks for bringing it to DJI and our attention.

DAFlys Posted at 11-28 01:12
Does it always happen or just where there is high contract between the snow and the trees?

I've only flown it twice outside so it's hard to tell. Here's a sample from my other flight:

https://drive.google.com/file/d/1qPTrfoIY1DYf3LZPxMCKknbQJVCMngxf/view?usp=sharing

In this sample I don't really see the pulsing, even though it's a pretty contrasty scene as well.

Have you tried to lock the AE and see if it's still happen please?

CYLSTUDIO Posted at 11-28 04:39
Have you tried to lock the AE and see if it's still happen please?

If you read my original post you can see that in the first sample with the pulsing, exposure was locked.

vdefilippo Posted at 11-28 04:55
If you read my original post you can see that in the first sample with the pulsing, exposure was locked.

Ah....got it.  Damn, then that's not good.

Very weird I haven´t used locked exposure yet, may go out right now to test that on mine.

CYLSTUDIO Posted at 11-28 05:30
Ah....got it.  Damn, then that's not good.

No, not good at all. For my purposes, it renders the drone useless.

I've created another thread where I post my results, the link is here: https://forum.dji.com/forum.php?mod=viewthread&tid=203144
I guess is not a real Lock EV, is like turning "auto" off every second or so.

InspektorGadjet Posted at 11-28 11:01
I've created another thread where I post my results, the link is here: https://forum.dji.com/forum.php?mod=viewthread&tid=203144
I guess is not a real Lock EV, is like turning "auto" off every second or so.

I looked at your samples and I don't really see the pulsing. Certainly not as clearly as in mine. Do you see it in yours?

Seems it is the same thing as first Mavic Pro struggling

vdefilippo Posted at 11-28 14:42
I looked at your samples and I don't really see the pulsing. Certainly not as clearly as in mine. Do you see it in yours?

Yes it is deffinitely there, I guess there was some sort of compression, since they are 2.7K shoots and I cannot choose anything bigger than 720 and many artifacts, however, upon close inspection of the files in several screens I can confirm is there.

I have the same problem with pulsing in video. Pulse rate approximately 1 second.

Exposure was locked.

UltraONE Posted at 11-29 03:57
I have the same problem with pulsing in video. Pulse rate approximately 1 second.

Exposure was locked.

Let's hope support says something, I did a separate post indicating my issue, but so far Support hasn't said anything there.

I think I'll do a test with a shot switching from locked to unlocked exposure.

Okay, so I went out today for another flight. Here's a sample on full auto. I can clearly see the pulsing. Once you're looking for it, it's painfully obvious.
By the way, I noticed another issue. On my flight today, I must have forgotton to stop recording when I shut off the drone. The last mp4 file is now corrupt. On my Mavic Air, if you forget to stop recording when you shut off the drone, it still saves the file properly.

Hello DJI, are you reading this?

https://drive.google.com/open?id ... Mn1u2YGnsAOD_r8E1Ft

vdefilippo Posted at 12-4 09:59
Okay, so I went out today for another flight. Here's a sample on full auto. I can clearly see the pulsing. Once you're looking for it, it's painfully obvious.
By the way, I noticed another issue. On my flight today, I must have forgotton to stop recording when I shut off the drone. The last mp4 file is now corrupt. On my Mavic Air, if you forget to stop recording when you shut off the drone, it still saves the file properly.

Apparently this happened to other Mavics too in the past, and is not something DJI can fix.
Pavel answer in my post with a good explanation of what is causing this effect.
Link to my post: https://forum.dji.com/thread-203144-1-1.html

This is his message:

I believe what you are seeing is a known artifact of imperfect video coding caused by accumulated error in GOP sequence that becomes visible on next I frame (because the error vanishes suddenly). The "breathing" occurs in your video at slightly more than one second distance (take a loudly ticking clock to see for yourself) and this well correlates with the fact that I frames in this video occur every 30 frames (while the video is 25 fps). You can see frame types by running:
ffprobe.exe -select_streams v -show_frames -show_entries frame=pict_type -of csv DJI_0057_EV_LOCKED.MP4
(you will also see that there are only I and P frames and no B frames which is sad).

The video with waterfall that you gave a link to is 30 fps and the "breathing" there occurs exactly each second while the I frames distance is again 30 frames so this supports my guess.

Unfortunately, video encoding in low-power CPUs (Mavic Mini has Ambarella H22) is usually performed by certain hardware, not software, so I would not count on firmware fix in the future.

I had the same problem today with video from my DJI Osmo Pocket.  Were you able to get a solution or resolution to your problem?  is there a way to correct the pulsing brightness problem in iMovie?

fanse9dd47ac Posted at 1-12 18:38
I had the same problem today with video from my DJI Osmo Pocket.  Were you able to get a solution or resolution to your problem?  is there a way to correct the pulsing brightness problem in iMovie?

I contacted DJI support. They looked at my video samples and had me update the firmware and do a couple of calibrations. That didn't work, so they asked me to send the drone in for repair. I don't have any news from them yet about that because it's still in transit.

vdefilippo Posted at 2019-12-4 09:59
Okay, so I went out today for another flight. Here's a sample on full auto. I can clearly see the pulsing. Once you're looking for it, it's painfully obvious.
By the way, I noticed another issue. On my flight today, I must have forgotton to stop recording when I shut off the drone. The last mp4 file is now corrupt. On my Mavic Air, if you forget to stop recording when you shut off the drone, it still saves the file properly.

That still happens on the latest firmware.  If you shut the Mini down while it is recording a video, that whole video is then unreadable, at least with what I have.

So you need to be super careful to shut off the video recording before powering the drone off.  I hope DJI can fix that in a future update.  They could make it stop recording and then properly close the file and then power down.  Its a shame to lose a whole video just because you switched the drone off.

Sigmo Posted at 1-12 19:43
That still happens on the latest firmware.  If you shut the Mini down while it is recording a video, that whole video is then unreadable, at least with what I have.

So you need to be super careful to shut off the video recording before powering the drone off.  I hope DJI can fix that in a future update.  They could make it stop recording and then properly close the file and then power down.  Its a shame to lose a whole video just because you switched the drone off.

That really sucks. On my Mavic Air, it saves the file properly if you shut down while recording. I hope they fix this with a firmware update.

I think it’s very hard to see, I’ve seen focus pumping before but this is hardly noticeable, it’s usually caused in high contrast scenes as Dafly said .

Sigmo Posted at 1-12 19:43
That still happens on the latest firmware.  If you shut the Mini down while it is recording a video, that whole video is then unreadable, at least with what I have.

So you need to be super careful to shut off the video recording before powering the drone off.  I hope DJI can fix that in a future update.  They could make it stop recording and then properly close the file and then power down.  Its a shame to lose a whole video just because you switched the drone off.

This may be off topic but to comment on your issue with the corrupted video, see this web site for a free utility program "djifix" to recover the video. The author has recently added the Mini to the compatibility list as of January 2020 .
http://djifix.live555.com/

GaryDoug Posted at 2-9 15:36
This may be off topic but to comment on your issue with the corrupted video, see this web site for a free utility program "djifix" to recover the video. The author has recently added the Mini to the compatibility list as of January 2020 .
http://djifix.live555.com/

Thanks. I'll check that out!

So, I got my drone back from DJI repair. It seems they just replace the mainboard and sent it back. I've had a chance to fly it a few times and, unfortunately, it seems the same. I can still identify the pulsing in pretty much every video. Depending on the scene, it's sometimes more, sometimes less evident but once you know what you are looking for, you can see it.

With a brand new motherboard, I can only conclude that this is "normal' for the Mavic Mini. Which sucks, because it really degrades the video quality.

Just realised this thread's been around for a while, but I wanted to jump in. I was doing some night videography meant for the BBC News yesterday using my Mavic Pro 2 and ran into the same problem: there's this pulsing happening every second. Has anyone come across a solution to this?

fans60851e64 Posted at 11-16 15:40
Just realised this thread's been around for a while, but I wanted to jump in. I was doing some night videography meant for the BBC News yesterday using my Mavic Pro 2 and ran into the same problem: there's this pulsing happening every second. Has anyone come across a solution to this?

See post 19 for what I think is the correct answer to this problem. Basically, can't be fixed.

https://forum.dji.com/forum.php? ... 092&pid=2023089