Please select Into the mobile phone version | Continue to access the computer ver.
4K compression is bad
385 16 4-17 04:00
Uploading and Loding Picture ...(0/1)
o(^-^)o
andrei193
First Officer
Flight distance : 1007 ft
Romania
Offline

Hi DJI,
Can you tell me if this kind of image compression is to be expected from the Mini 2?
I use a sandisk 64 extreme card and when shooting in 2.7k this problem does not seem to appear.

this is the link to the video: https://drive.google.com/file/d/ ... j3/view?usp=sharing
this is the link to the screengrab: https://drive.google.com/file/d/ ... GC/view?usp=sharing
this is 100% crop:
100%crop.jpg

4-17 04:00
Use props
Ten182
lvl.1
Flight distance : 55640 ft

Italy
Offline

Just today I noticed a difference between 2.7k and 4k, i think the 4k looks better, now I'm trying to do some tests, but in none of the cases it looks so muuch pixelated like your case, I think it's a problem with your drone, but i don't have any suggestion, im sorry.
4-17 09:38
Use props
Tuxtard
Second Officer
Flight distance : 251719 ft
Serbia
Offline

This model generally has a problem with motion. There are quite few topics related to this issue, for instance:

https://forum.dji.com/forum.php?mod=viewthread&tid=240032
https://forum.dji.com/forum.php?mod=viewthread&tid=238722
https://forum.dji.com/forum.php?mod=viewthread&tid=238479
https://forum.dji.com/forum.php?mod=viewthread&tid=236479

But yours looks much worse. Is this footage zoomed in or enlarged in post?
4-19 08:04
Use props
andrei193
First Officer
Flight distance : 1007 ft
Romania
Offline

The picture wich is seen here is a 100% crop (zoomed). It doesn't always produce footage like this, only when flying close to the ground and there's a lot of green areas with detail. Switching to 2.7k resolves the problem. I think it's a compression problem that has to do with the camera and processor limitation.
4-19 08:09
Use props
Tuxtard
Second Officer
Flight distance : 251719 ft
Serbia
Offline

andrei193 Posted at 4-19 08:09
The picture wich is seen here is a 100% crop (zoomed). It doesn't always produce footage like this, only when flying close to the ground and there's a lot of green areas with detail. Switching to 2.7k resolves the problem. I think it's a compression problem that has to do with the camera and processor limitation.

Don't know what 100% crop is, but it is known that this drone has a problem with fast motion and surfaces like grass or gravel. Not sure if this problem is related to encoder, sensor or both, but since DJI is ignoring these topics I think that it is well known to them and not fixable. Only thing you can do in these circumstances is to use ND filters to convert this noisy mess into more acceptable blurry video.
4-19 10:43
Use props
Geebax
Captain
Australia
Offline

Tuxtard Posted at 4-19 10:43
Don't know what 100% crop is, but it is known that this drone has a problem with fast motion and surfaces like grass or gravel. Not sure if this problem is related to encoder, sensor or both, but since DJI is ignoring these topics I think that it is well known to them and not fixable. Only thing you can do in these circumstances is to use ND filters to convert this noisy mess into more acceptable blurry video.

"but it is known that this drone has a problem with fast motion and surfaces like grass or gravel."

Partly true. ALL the DJI drones have this problem. The OP has shot footage of a close-up vertical shot while flying quickly aver a grass lawn. No matter what camera you use (outside of pro cinema cameras), you will get a poor result from this type of shot. The maximum bit-rate of the camera is 100 Mb/s, which is too low to capture fast changing images like that. DJI could implement a faster bit-rate, but then you would not be able to use standard off-the-shelf SD cards to record the images. It would require expensive CFast cards or mini-SSD drives, and there is a space and weight penalty to using those devices.

The solution is to recognise the limitations of the camera and shoot accordingly. Avoid fast movement and scenes with excessive high detail. Fast movement over fine detail overloads the MPEG encoding processor, if you look at the end of that shot, it looks fine as soon as the fly-over ends.


4-19 16:16
Use props
dji_MODDER
Captain
Flight distance : 11588 ft
Netherlands
Offline

link to your video shows a 1080p recording not a 2.7k
4-19 22:24
Use props
ozoffi
Second Officer
Flight distance : 30459 ft
Austria
Offline

"In these circumstances, all you can do is use ND filters to convert this noisy mess into more acceptable blurry video."
Casting out the devil with the devil's clover...
4-19 22:28
Use props
Tuxtard
Second Officer
Flight distance : 251719 ft
Serbia
Offline

dji_MODDER Posted at 4-19 22:24
link to your video shows a 1080p recording not a 2.7k

GDrive streams only in 1080p. For full resolution you have to download it.
4-20 01:51
Use props
andrei193
First Officer
Flight distance : 1007 ft
Romania
Offline

Thanks everyone for your input! I figured this is a limitation of the product. I am quite satisfied with how 2.7k performs. Unfortunately, the gimbal issue post I made turns out that it does not behave normaly after contacting DJI and I have sent it for a replacement.
4-20 02:32
Use props
ABeardedItalian
First Officer
Flight distance : 1034633 ft
United States
Offline

Geebax Posted at 4-19 16:16
"but it is known that this drone has a problem with fast motion and surfaces like grass or gravel."

Partly true. ALL the DJI drones have this problem. The OP has shot footage of a close-up vertical shot while flying quickly aver a grass lawn. No matter what camera you use (outside of pro cinema cameras), you will get a poor result from this type of shot. The maximum bit-rate of the camera is 100 Mb/s, which is too low to capture fast changing images like that. DJI could implement a faster bit-rate, but then you would not be able to use standard off-the-shelf SD cards to record the images. It would require expensive CFast cards or mini-SSD drives, and there is a space and weight penalty to using those devices.

Just being that guy, but with a UHS-II sdcard/microsd you can capture @4k 10bit at 400mbit. So... if DJI supported UHS-II and or standard sdcards they could provide a 4x bitrate improvement.

Back to the topic at hand, this should help those understand why grass and things can cause digital distortion.
4-20 04:06
Use props
Tuxtard
Second Officer
Flight distance : 251719 ft
Serbia
Offline

ABeardedItalian Posted at 4-20 04:06
Just being that guy, but with a UHS-II sdcard/microsd you can capture @4k 10bit at 400mbit. So... if DJI supported UHS-II and or standard sdcards they could provide a 4x bitrate improvement.

Back to the topic at hand, this should help those understand why grass and things can cause digital distortion.

Thanks for the clarification, but I am not sure that this is 100% related to Mini 2 issue as the problem is way more noticable here compared to other models.
4-20 12:27
Use props
Tuxtard
Second Officer
Flight distance : 251719 ft
Serbia
Offline

andrei193 Posted at 4-20 02:32
Thanks everyone for your input! I figured this is a limitation of the product. I am quite satisfied with how 2.7k performs. Unfortunately, the gimbal issue post I made turns out that it does not behave normaly after contacting DJI and I have sent it for a replacement.

Please tell us if the 4k quality is the same or better on the replacement.
4-20 12:29
Use props
dji_MODDER
Captain
Flight distance : 11588 ft
Netherlands
Offline

Tuxtard Posted at 4-20 01:51
GDrive streams only in 1080p. For full resolution you have to download it.

Thanks for the call
4-20 22:24
Use props
Montfrooij
Captain
Flight distance : 1981040 ft
Netherlands
Offline

I actually only shoot 2.7K.
I don't see much difference between 4 - 2.7 to justify the extra filesize and render times.
4-21 00:38
Use props
ABeardedItalian
First Officer
Flight distance : 1034633 ft
United States
Offline

Tuxtard Posted at 4-20 12:27
Thanks for the clarification, but I am not sure that this is 100% related to Mini 2 issue as the problem is way more noticable here compared to other models.

You are correct and part of that is the bit rate is limited to 100 on the mini 2, the larger mavic pro/air2's shoot at 140+ and do a better job dealing with situations like this.

I was simply pointing out that you don't need Cf Express or SSD's to capture a higher bitrate, If Fuji can record 10bit HDR at 400Mbit to those UHS-ii cards then why would you need something larger? DJI could update support for UHS-II but is unlikely, but then you could record at a 4x bitrate the current mini 2 supports.
4-21 03:26
Use props
Huginn Kenningar
Second Officer
Flight distance : 8970814 ft
Spain
Offline

With high shutter speed, high frequency objects (grass, terrain) etc, may produce those artifacts.

It's a little mobile phone camera sensor, so I doubt it's even recording at real 4K, counting every pixel, every frame.

This doesn't happen in the Air2S for exampe, but it's a proper sensor, with a more powerful CPU onboard and also using H265 at 150mbps instead of H264 100mbps
4-21 17:00
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules