Please select Into the mobile phone version | Continue to access the computer ver.
Phantom 4 Pro camera is really 4K?
366 25 2017-9-13 21:21:48
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

I have a Phantom 4 pro a few months ago already, but almost since the beginning I was not too much impressed with the quality obtained, specially with the 4K videos, now I think that could be due to a technical feature that I wish to be very very wrong about it.

In these 3 100% crops are something in common: signals of interpolation or deinterlacing, as you can see in the stairs like artifacts on each diagonal and line captured by the P4P camera, this kind of artifacts can be found on deinterlaced footage converted to progressive or in FullHD upscaled to 4k:
crop1.png crop2.png crop3.png

so... P4P camera is really 4K? I have another 4K cameras and none of their footage presents this kind of artifacts.

These are the details of the video where the crops were taken:
https://www.dropbox.com/s/ovstiwrj3cchjhr/video_details.jpg?dl=0

2017-9-13 21:21:48
Use props
PaulSouthport
Second Officer
Flight distance : 352040
United Kingdom
Online

Is the video from the SD card or the mobile device?


EDIT: ignore that, I missed the dimensions on the clip
2017-9-13 22:26:25
Use props
method007
Second Officer
Flight distance : 5333
United States
Offline

Yup, it's 4K.  It's just not the best.  
2017-9-14 06:43:00
Use props
Capt Whitefoot
lvl.4
United States
Offline

I'm not sure what the situation is with your P4P, but with mine, it shoots exceptional 4k.  It makes 1080p look way lower quality.
2017-9-14 07:16:54
Use props
Nigel_
First Officer
Flight distance : 83281
United Kingdom
Offline

It doesn't have a 4K image sensor, the sensor is bigger than 4K but not a nice 2x so a perfect scaling is not possible.

Most of your image looks like decent 4K though, maybe a little out of focus on the closer bits of the bridge.

I wonder if the issue you are seeing is a result of stabilisation trying to remove vibrations?
Are your propellers well balanced or do they vibrate a lot?
2017-9-14 07:59:34
Use props
SM-17
lvl.4
Flight distance : 41427
Malta
Offline

What sharpness settings are you using?
2017-9-14 08:29:51
Use props
gt3rs
lvl.3
Flight distance : 85361
Switzerland
Offline

up to 4k 30fps the quality is quite good and better than most small sensor cameras e.g. gopro, mavic, phones but above 30fps p4p is doing line skipping so it introduces aliaising and you loose vertical resolution.... try filming at home without flying a test chart or news paper at 4k 30 and 60 and compare.
2017-9-14 12:10:25
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

Nigel_ Posted at 2017-9-14 07:59
It doesn't have a 4K image sensor, the sensor is bigger than 4K but not a nice 2x so a perfect scaling is not possible.

Most of your image looks like decent 4K though, maybe a little out of focus on the closer bits of the bridge.

Well I was sure the conditions were as stable as P4P can offer, and in this matter it does a very good job, it seems like line skipping or a kind of de-interlacing.
2017-9-14 20:57:49
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

gt3rs Posted at 2017-9-14 12:10
up to 4k 30fps the quality is quite good and better than most small sensor cameras e.g. gopro, mavic, phones but above 30fps p4p is doing line skipping so it introduces aliaising and you loose vertical resolution.... try filming at home without flying a test chart or news paper at 4k 30 and 60 and compare.

Thanks a lot for your comment, and well, I think you are right, I've compared with another 4K@30fps footage and I couldn't found the same issue, so certainly is line skipping, perhaps to achieve the higher frame rate, thus, the conclusion could be that P4P is not a real 4K/UHD at 60fps, that is a quite bad news because must of the cases people shoot at 60fps for slow motion where the artifacts became even more visible. This is a huge negative point for P4P.
2017-9-14 21:08:00
Use props
Geebax
Captain
Australia
Offline

fansde3bbad0 Posted at 2017-9-14 21:08
Thanks a lot for your comment, and well, I think you are right, I've compared with another 4K@30fps footage and I couldn't found the same issue, so certainly is line skipping, perhaps to achieve the higher frame rate, thus, the conclusion could be that P4P is not a real 4K/UHD at 60fps, that is a quite bad news because must of the cases people shoot at 60fps for slow motion where the artifacts became even more visible. This is a huge negative point for P4P.

It is not line skipping. To do that the sensor must have a vertical resolution at least equal to twice the target vertical resolution, otheriwse you would see horendous aberrations in the picture. The answer is shown in the properties window of the OP's grab. Look at the properties.
2017-9-14 21:52:54
Use props
Montfrooij
First Officer
Netherlands
Online

Nigel_ Posted at 2017-9-14 07:59
It doesn't have a 4K image sensor, the sensor is bigger than 4K but not a nice 2x so a perfect scaling is not possible.

Most of your image looks like decent 4K though, maybe a little out of focus on the closer bits of the bridge.

You might be on the right track with the stabilization and the scaling down.
2017-9-15 01:16:52
Use props
Montfrooij
First Officer
Netherlands
Online

Geebax Posted at 2017-9-14 21:52
It is not line skipping. To do that the sensor must have a vertical resolution at least equal to twice the target vertical resolution, otheriwse you would see horendous aberrations in the picture. The answer is shown in the properties window of the OP's grab. Look at the properties.

I'm missing it I guess.
2017-9-15 01:18:27
Use props
DJI Diana
Administrator
Japan
Offline

If you could upload an original 4k video from the SD card to the Dropbox, then provide me a link to download it, I'll forward it to our engineer for analysis.
2017-9-15 01:26:46
Use props
Sebb
lvl.4
Flight distance : 49107
Germany
Offline

The P4p sensor is the same as in the Sony RX100m4, so we know a fair bit about it. So YES, it is true 4K. Quite good 4K, actually!

However, the main point to keep in mind is: you cannot compare a video still to a JPEG photo, in case that is what you did...  it will always look considerably less sharp  (that goes for practically all cameras)

Why?

image processors use shortcuts to handle the massive amount of image data coming off sensors.
1. Pixel binning / line skipping = not all pixels are used to compile the image. P4p has 20MP sensor and will only use a portion of the total 20mio pixels to create an 8MP = 4K image frame. this results in significant loss of sharpness, moire and aliasing (compared to a native 8MP photo).
2. Chroma Subsampling = color information from 4 pixels are combined and averaged into 1. that results in noticeable loss in clarity.

bottomline.. on basically every camera, video frames will look nowhere near as good as photos off the same sensor, even at same resolution.
what other 4K cameras do you have / are you comparing?

disclaimer: half-baked amateur talking here . ..


2017-9-15 01:56:56
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

Sebb Posted at 2017-9-15 01:56
The P4p sensor is the same as in the Sony RX100m4, so we know a fair bit about it. So YES, it is true 4K. Quite good 4K, actually!

However, the main point to keep in mind is: you cannot compare a video still to a JPEG photo, in case that is what you did...  it will always look considerably less sharp  (that goes for practically all cameras)

One of the reasons I decided for P4P was just Sony is using the same sensor.

The crops were extracted from a 4k@60fps video, aren't stills, they were encoded carefully to avoid another artifacts different to the mentioned one in this post, the issue is clearly regular, is not due to compression, or something similar, we can see an ordered pattern just one scanline after another, like the ones we can see in a de-interlaced or line-skipped video frame.

I can confirm the issue is only present in 4k@60fps videos not in 4k@30fps, so must be something associated with the framerate.
2017-9-16 13:34:16
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

DJI Diana Posted at 2017-9-15 01:26
If you could upload an original 4k video from the SD card to the Dropbox, then provide me a link to download it, I'll forward it to our engineer for analysis.

Hi,

Well, the video I use for the crops is quite long and big, so I uploaded a couple of short ones where the issue can be noted too:


Video Link:
http://3dlogical.com/_temp/dji/DJI_0061.MOV

You can note the issue on the white lines over the field


Video Link:
http://3dlogical.com/_temp/dji/DJI_0018.MOV

You can note the issue looking at the mountains silhouette.

These videos are unprocessed, unedited, untouched

2017-9-16 14:11:18
Use props
lannes
lvl.4
Australia
Online

Could it be something to do with SD Card write speed ?
2017-9-16 22:40:47
Use props
Geebax
Captain
Australia
Offline

lannes Posted at 2017-9-16 22:40
Could it be something to do with SD Card write speed ?

The SD card has nothing whatsoever to do with the image quality. It is a digital recording, not analog.
2017-9-16 23:10:34
Use props
Geebax
Captain
Australia
Offline

fansde3bbad0 Posted at 2017-9-16 14:11
Hi,

Well, the video I use for the crops is quite long and big, so I uploaded a couple of short ones where the issue can be noted too:

'These videos are unprocessed, unedited, untouched'

The videos might be, but the crops certainly are not. You cannot expect to crop an image like that without creating distortions. The short clip you linked to looks perfect, why are you pixel-peeping?
2017-9-16 23:17:36
Use props
Sebb
lvl.4
Flight distance : 49107
Germany
Offline

fansde3bbad0 Posted at 2017-9-16 13:34
One of the reasons I decided for P4P was just Sony is using the same sensor.

The crops were extracted from a 4k@60fps video, aren't stills, they were encoded carefully to avoid another artifacts different to the mentioned one in this post, the issue is clearly regular, is not due to compression, or something similar, we can see an ordered pattern just one scanline after another, like the ones we can see in a de-interlaced or line-skipped video frame.

yes of course high framerates always results in significantly decreased image clarity.
4K60 on P4pro is usable but nowhere near 4K30.
4 days ago
Use props
DJI Diana
Administrator
Japan
Offline

fansde3bbad0 Posted at 2017-9-16 14:11
Hi,

Well, the video I use for the crops is quite long and big, so I uploaded a couple of short ones where the issue can be noted too:

Thanks, I've forwarded them to our engineers, will keep you updated.
4 days ago
Use props
charlesetischer
lvl.1
Canada
Offline

The sensor of P4P has about 5470 pixels horizontally and the 4K video is down-scaled from the 5.4K RAW, thus making it sharper and less noisy than directly cropping a 4K window on the sensor.

Unlike 4K 30fps which has square pixels, the 4K 60fps footage is generated from 5.4K RAW with rectangular logical pixels. This technique allows to make full use of the same area of the sensor as that in 4K 30fps mode and keep the full FOV, without sacrificing dynamic range (compared to 4K windowed readout). It is beyond the performance limit of the sensor to readout 5.4K square pixels at a rate of 60fps.
4 days ago
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

Geebax Posted at 2017-9-16 23:17
'These videos are unprocessed, unedited, untouched'

The videos might be, but the crops certainly are not. You cannot expect to crop an image like that without creating distortions. The short clip you linked to looks perfect, why are you pixel-peeping?

You must have in mind what 100% crop means, they are unscaled 320x320, undistorted, unprocessed images extracted directly from a video frame, and uncompressed because were stored in PNG, so there are no chances to incorporate distortion of any kind from anywhere, any artifact that you could see in those crops actually exists in the video. To obtain unaltered crops of a video I use AfterEffects or Photoshop TimeLine, the video frame is saved directly from a selected frame on the timeline in PNG format, cropped and stored in PNG again, there is no chance that in such as process some distortion, compression artifact or visual contamination be incorporated. But with the video links I provided you can do the crops by yourself and see what I'm seen by your own.
4 days ago
Use props
fansde3bbad0
lvl.1
Flight distance : 52988
Colombia
Offline

fansde3bbad0 Posted at 2017-9-18 08:27
You must have in mind what 100% crop means, they are unscaled 320x320, undistorted, unprocessed images extracted directly from a video frame, and uncompressed because were stored in PNG, so there are no chances to incorporate distortion of any kind from anywhere, any artifact that you could see in those crops actually exists in the video. To obtain unaltered crops of a video I use AfterEffects or Photoshop TimeLine, the video frame is saved directly from a selected frame on the timeline in PNG format, cropped and stored in PNG again, there is no chance that in such as process some distortion, compression artifact or visual contamination be incorporated. But with the video links I provided you can do the crops by yourself and see what I'm seen by your own.

This is a screen recording showing the process I did to extract 100% crops and compare the differences between 4K@60fps and 4K@30fps of the same subject with the same lighting and ambient conditions, I drop here the links of the videos used for the analysis and the 100% crops extracted from them just made at my house:

Process:
http://3dlogical.com/_temp/dji/ProcessCapture.mp4

4K video at 60fps:
http://3dlogical.com/_temp/dji/DJI_0344.MOV

4K video at 30fps:
http://3dlogical.com/_temp/dji/DJI_0345.MOV

100% Crop 1 at 60fps:
http://3dlogical.com/_temp/dji/Crop@60fps.png

100% Crop 2 at 30fps:
http://3dlogical.com/_temp/dji/Crop@30fps.png

So I hope this is much more clear and generate less confusion  about the cropping and extracting process..
4 days ago
Use props
R&L Aerial
Captain
Flight distance : 90861
  • >>>
United States
Offline

You may have a defective unit, my p4 advanced shots great 4k
4 days ago
Use props
DJI Diana
Administrator
Japan
Offline

fansde3bbad0 Posted at 2017-9-16 14:11
Hi,

Well, the video I use for the crops is quite long and big, so I uploaded a couple of short ones where the issue can be noted too:

Hi, our engineers replied you in the post 22#, please check it.
4 days ago
Use props
You need to log in before you can reply Login | Register now

Credit Rules

Close

DJI RecommendsPrevious /1 Next