OK, this is weird. I have a clip of a high aerial, and a cloud's shadow is passing over the cornfield below. The shadow's movement across the landscape is jerky while the rest of the movement is smooth.  It sucks because I love the look of the moving cloud cover, but I can't use it like this!

All other video shot that day looks good - movement isn't choppy, landscape passing under the camera is smooth, details like rippling and water and leaves moving in the wind all look natural, nothing like this large shaded area moving in distinct jerks.
I shot it in D-log with an image size of 3840 x 2160 and frame rate 29.97.

I see the choppiness when I preview the original clip in Windows 7 Media Player, and at every stage in Adobe Premiere Pro, too. The link below is an edited export from Adobe.

Here is a link to the original file copied directly from the SD card. Download this and check it out.

https://drive.google.com/open?id=1Zsm15qQUGQj0tUOK0J0kJvVpUcA6D5Z1

If you just look at Google's preview playback, you'll see degraded quality from Google's processing. To see and work with the original, you really need to download the entire file to view on your system.

Is this the camera's compression that is treating the shadow area so differently from the rest of the image?
Unfortunately, it's not that easy a phenomenon to replicate! You need a partly cloudy, windy day, with big chunks of clouds scudding across the sky. But for now, maybe it is best to stick with 2.7 instead of 4k...?

Sorry No Idea why, but very interested in the answer.

Seeing other discussions of what might be the same thing. People are suggesting this stuttering only occurs at 4k, but not 2.7k.  Hmm.

https://forum.dji.com/thread-56116-1-1.html

Hi, there. Thank you for reaching out and we do apologize for the inconvenience. There is a possibility that the computer you are using can't render the quality of 4k and it causes the frame to drop. Can you please try to play the video file on a different pc with a high-end graphics to see if the problem will still persist. Also, if there is a possibility that you can try to shoot this in a lower resolution and check whether it will provide you the same issue for us to further help you with this one. Please keep us posted. Thank you for your kind and understanding. Cheers!

DJI Gamora Posted at 6-19 08:48
Hi, there. Thank you for reaching out and we do apologize for the inconvenience. There is a possibility that the computer you are using can't render the quality of 4k and it causes the frame to drop. Can you please try to play the video file on a different pc with a high-end graphics to see if the problem will still persist. Also, if there is a possibility that you can try to shoot this in a lower resolution and check whether it will provide you the same issue for us to further help you with this one. Please keep us posted. Thank you for your kind and understanding. Cheers!

The computer I'm using is a Windows 7 machine, with an Nvidia P4000 card in it, so it seems unlikely that it wouldn't be able to handle the 4k. And if frames were being dropped, then the portions of the video that don't include the cloud shadow would also appear jerky - but they don't. None of the other footage I shot that day has the same jerkiness.

Unfortunately, it would be difficult to recreate these weather conditions so I can test 2.7k against 4k! But if a partly cloudy day pops up anytime soon where clouds are racing across the sky, I'll try it!

danmckinney Posted at 6-19 08:58
The computer I'm using is a Windows 7 machine, with an Nvidia P4000 card in it, so it seems unlikely that it wouldn't be able to handle the 4k. And if frames were being dropped, then the portions of the video that don't include the cloud shadow would also appear jerky - but they don't. None of the other footage I shot that day has the same jerkiness.

Unfortunately, it would be difficult to recreate these weather conditions so I can test 2.7k against 4k! But if a partly cloudy day pops up anytime soon where clouds are racing across the sky, I'll try it!

Thanks for your prompt reply. I'm positive that in no time you will come across with that weather condition again and I hope you can capture the moment as soon as possible. Once you have that footage available, please feel free to post it here so that we can compare it to your old footage and see what is the main problem. You can post it via google-drive or Dropbox and provide the link here. Again, sorry for the trouble that it caused and we appreciate your continued support.

I'd say your computer is the problem here

AJC-W Posted at 6-19 12:30
I'd say your computer is the problem here

The clip I posted was exported with Premiere Pro at the same frame rate as the source file. If it was my computer not rendering the playback properly, why would the jerkiness still be visible in a rendered file uploaded to Vimeo?

Are you saying that my system is introducing this jerkiness not in playback, but in the rendering process?

I've been shooting and editing 1080 and 4k for years with this system, but have never seen anything quite like this. And while it's true that 4k is more difficult to work with & preview in Premier Pro while editing, rendered clips don't show any stopping or stuttering.

To me, the fact that the cloud shadow moves in jerks across the frame while the other movement is smooth suggests that it's an artifact of the camera's compression process.
I'll upload the raw file so people can look for themselves.

danmckinney Posted at 6-20 03:15
The clip I posted was exported with Premiere Pro at the same frame rate as the source file. If it was my computer not rendering the playback properly, why would the jerkiness still be visible in a rendered file uploaded to Vimeo?

Are you saying that my system is introducing this jerkiness not in playback, but in the rendering process?

May be take the SD card to a friend or family members house who use say an iMAC with Final Cut and gauge the difference. If the issue persists then you know for sure that it is the drone and may be caused by the compression. Until then it will just be a guessing game which is why I presume you opened the thread with several questions and no definitive answers.

AJC-W Posted at 6-19 12:30
I'd say your computer is the problem here

uploading the file now - I'll post the link once it's up, and I would really appreciate it if you could take a look and tell me if you see the same thing!!

https://drive.google.com/open?id ... UOK0J0kJvVpUcA6D5Z1

You can download the original file here. Let me know what you see! Is the cloud shadow moving in jerks across the frame while the rest of the scene is moving smoothly?
This is the entire 1:20 file - what I posted earlier on Vimeo was an edited clip of a few seconds. With the full-length file you can more easily contrast the jerky shadow movement at the start of the file with the smooth movement of the landscape in the last half of the file.

Let me know what you see!

AJC-W Posted at 6-19 12:30
I'd say your computer is the problem here

I this was the problem, the background would be also jerky... and it is not... only the cloud shadow....

danmckinney Posted at 6-20 03:48
https://drive.google.com/open?id=1Zsm15qQUGQj0tUOK0J0kJvVpUcA6D5Z1

You can download the original file here. Let me know what you see! Is the cloud shadow moving in jerks across the frame while the rest of the scene is moving smoothly? That's what I think I'm seeing...

Try importing the files again from the micro SD card to another PC/Mac - sharing the link to the existing import/edit will just show the same result that you see. It's not just the motion of the clouds but the whole footage looks poorly rendered with limited details. It could also be your micro sd card no having fast enough read/write speeds.

AJC-W Posted at 6-20 04:19
Try importing the files again from the micro SD card to another PC/Mac - sharing the link to the existing import/edit will just show the same result that you see. It's not just the motion of the clouds but the whole footage looks poorly rendered with limited details. It could also be your micro sd card no having fast enough read/write speeds.

This is not an edit. This is the original file copied directly from the SD card and uploaded, intact, to my Google drive. It is bit for bit identical to the file on the SD card.

Download it and check it out.

ro_flyer Posted at 6-20 04:18
I this was the problem, the background would be also jerky... and it is not... only the cloud shadow....

The motion of the trees swaying in the wind is also jerky and the resolution is massively compromised - this looks like 240p rather than 4K.

AJC-W Posted at 6-20 04:22
The motion of the trees swaying in the wind is also jerky and the resolution is massively compromised - this looks like 240p rather than 4K.

Did you download it to view it? Or did you look at the Google Drive rendering? You need to download the file.
Google compresses the file for playback - it's not going to be the same as downloading it and viewing the original resolution. Also, as it was shot in D-log, it will look a bit washed-out.

danmckinney Posted at 6-20 04:21
This is not an edit. This is the original file copied directly from the SD card and uploaded, intact, to my Google drive. It is bit for bit identical to the file on the SD card.

Download it and check it out.

That's why I said import/edit i.e. the import if not edited. As I said, this is either the limitations of your computer or your micro SD card or a fault with your drone. I have seen hundreds of Mavic Pro videos (including those of my own with that drone) and have never had these issues.

danmckinney Posted at 6-20 04:24
Did you download it to view it? Or did you look at the Google Drive rendering? You need to download the file.
Google compresses the file for playback - it's not going to be the same as downloading it and viewing the original resolution. Also, as it was shot in D-log, it will look a bit washed-out.

Unfortunately my Mac advises that it cant detect viruses for the google download so I'll have to pass on that one.

AJC-W Posted at 6-20 04:25
That's why I said import/edit i.e. the import if not edited. As I said, this is either the limitations of your computer or your micro SD card or a fault with your drone. I have seen hundreds of Mavic Pro videos (including those of my own with that drone) and have never had these issues.

If you download this file and view it on your system and see the same thing, then we know it's not anything to do with my system, yes?

So, when you download and view it, do you see the cloud jerkiness? And does the rest of the movement look smooth?

If you see the artifact on your end, then we can safely assume that the flaw exists within the file itself, not my system. Am I wrong?

danmckinney Posted at 6-20 04:31
If you download this file and view it on your system and see the same thing, then we know it's not anything to do with my system, yes?

So, when you download and view it, do you see the cloud jerkiness? And does the rest of the movement look smooth?

As I previously stated my Mac advises that it cant detect viruses if I do the download so apologies but I'm not running that risk. I wish you luck.

AJC-W Posted at 6-20 04:32
As I previously stated my Mac advises that it cant detect viruses if I do the download so apologies but I'm not running that risk. I wish you luck.

Well, it's not a virus. Any files over a certain size, Google won't scan, so the warning you see is posted by Google saying that they haven't scanned it.  But I assure you it's the file from the card. Can I DropBox it to you? I;d love to get another pair of eyes on this!

I checked the dowloaded file on a high end computer. And it shows the weird effects. Its not the common jerkyness, its just strange. My guess, too, would  be compression artifact. Think of the low contrast of the shadow, where the compression might fail.

DrohneSG Posted at 6-20 05:06
I checked the dowloaded file on a high end computer. And it shows the weird effects. Its not the common jerkyness, its just strange. My guess, too, would  be compression artifact. Think of the low contrast of the shadow, where the compression might fail.

Right!  Good to know my brain-and-or-eyeballs are simply fried from too much time editing. As I pointed out, another thread has observed similar cloud effects when shooting at 4K. I will try 2.7K next time the opportunity for cloud shadows arises!

danmckinney Posted at 6-20 05:13
Right!  Good to know my brain-and-or-eyeballs are simply fried from too much time editing. As I pointed out, another thread has observed similar cloud effects when shooting at 4K. I will try 2.7K next time the opportunity for cloud shadows arises!

Please let us know the results

ro_flyer Posted at 6-20 15:52
Please let us know the results

So, yesterday the rain stopped long enough for me to get back out and shoot 2.7k .  Same settings as before EXCEPT I switched to MP4 instead of MOV. But that change shouldn't make a difference - right? The compression algorithm is the same for both? H264

This time the cloud shadow moved much more smoothly!! Below is a link to a processed version (D-log LUT applied), but the raw file also moved smoothly. I can post the raw file a bit later for anyone who's interested.

And I'll need to follow up with another 4K cloud chaser to see if I can replicate that original jerkiness. If we see the jerkiness in the 4K but not the 2.7K, we'll know the culprit is the compression algorithm used at 4K - right?

Thanks for keeping us updated regarding this issue, mate!!

Only just saw your post ... :-) This is a known issue with the Mavic Pro camera codec doing temporal compression on areas of the frame with relatively low contrast - which are only updated every 8th frame. FYI a thread I started on the same subject https://forum.dji.com/thread-134524-1-1.html I found setting the frame rate to 25 fps and the shutter to 1/50 (PAL standard) solved the problem - but you'll need to also use an ND filter to control the exposure having manually set frame rate and shutter speed. As you are on the US TV standard that would be 30fps and 1/60th shutter speed plus ND filter. I use ND 32 most of the time  - and D-Log as I grade all my footage in the edit.

Lamplighter55 Posted at 6-22 08:03
Only just saw your post ... :-) This is a known issue with the Mavic Pro camera codec doing temporal compression on areas of the frame with relatively low contrast - which are only updated every 8th frame. FYI a thread I started on the same subject https://forum.dji.com/thread-134524-1-1.html I found setting the frame rate to 25 fps and the shutter to 1/50 (PAL standard) solved the problem - but you'll need to also use an ND filter to control the exposure having manually set frame rate and shutter speed. As you are on the US TV standard that would be 30fps and 1/60th shutter speed plus ND filter. I use ND 32 most of the time  - and D-Log as I grade all my footage in the edit.

Great info!! I was just about to inspect the file and see how many frames the cloud was frozen. Thank you for this!!

danmckinney Posted at 6-22 19:04
Great info!! I was just about to inspect the file and see how many frames the cloud was frozen. Thank you for this!!

You're welcome!  I forgot to add that basically don't use 'auto' mode for exposure. Frame rate and shutter speed are both on 'manual' setting.  Good luck for your next flights.

Will pick up some ND / polarizing filters today, bypass auto exposure and set frame rate to 30 and shutter speed to 1/60, and try it out at the same property late in the day. I had been advised in the past to keep my shutter speed at roughly twice what the frame rate was, but was told that it had to do with frames being dropped or skipped. By keeping shutter speed & frame rate at  even multiples, you can avoid skipped frames?

I can't quite say I understand the concept - is that indeed correct?