Hi,

I'm having a problem that I'm not sure if it's just the low quality camera problem, an issue specific to my drone or something else. I'm using a really high quality SD card but the footage I take off the drone always looks so horribly compressed that any grading whatsoever to the footage results in horrible pixalation noise of the colours. I'm shooting in 4k in D-Log and to be honest I've not done much testing with other cards etc, so I was hoping to save myself some time is others are seeing the same problem or know exactly what's causing such terrible quality and noise.

As you can see from these screenshots I have hopefully attached, you can really see the pixelation artifacts i'm refering to in the water which move around like grain/noise when played. I have over graded this on purpose to try and show what I mean, but even in places where there is more detail and not so over-graded you can see the pixelation noise really noticably when playing the video.

I hope the files are attached - sorry if they're not - I'm a first time poster.

Any help would be much appreciated!

Thanks!!!

What program are you using to process these shots? Are these stills or grabs from a video clip?

These are just screen grabs that aren't processed as all, just screen shot from FCPX. I edit/grade in premiere, ae, and or final cut depending on what i'm editing and the problem is exactly the same throughout all software. What you see in the screen grabs is an exact representation of what I see in the video with that horrible, noisy breakup between the colours. More detailed shots hide it better, but it is still evidently there. Certainly anything with sky in the shot, or water has the artefacts present.

Visual Blimp Posted at 2016-11-19 06:51
These are just screen grabs that aren't processed as all, just screen shot from FCPX. I edit/grade i ...

Hi, Can you post some specs of the videos taken.

Right click the Video file then select properties then details - show its frame width, height and data rate/total bitrate,

Total bitrate should be roughly 60,000kbps = 60mb per second

if its less than that and you are shooting 4k then its probably a low quality micro SD

C_LUU Posted at 2016-11-19 01:00
Hi, Can you post some specs of the videos taken.

Right click the Video file then select properti ...

Hi, I've just checked and it seems to be recording at 60mps. I guess it must be a problem with the camera?

Visual Blimp Posted at 2016-11-20 04:28
Hi, I've just checked and it seems to be recording at 60mps. I guess it must be a problem with the  ...

I have  the same problem, HD And 2K look great,  but 4K And UHD are horrible.I'm à professional vidéo editor, il use avid 8.6 and résolve 12.5.

That's good to know I'm not the only one. Let me know if you find an answer! It's very frustrating. I'm still not sure if this is a problem with the drone or something that everyone has because of the low quality??

Visual Blimp Posted at 2016-11-20 20:04
That's good to know I'm not the only one. Let me know if you find an answer! It's very frustrating.  ...

"I'm shooting in 4k in D-Log"
Using D-Log is part of the issue, it looses smoothness in the midrange to gain detail at the top and bottom. The files are only 8 bit so it is easy to enhance the resulting midrange blockyness to be visible.  If you are not going to use the extended range of the D-Log then stick to Normal.

Also, 60Mb/s is not a high rate for 4K, there will be some compression artefacts visible if you look carefully at 4K resolution.  Might help to add some low level dither to blend the edges of the blocks before adjusting the images, the 1080 may look better because it has some dither but with the 4K having less bits/pixel, the 4K has lost any dither in the compression so the blocks have sharp edges making them visible.

C_LUU Posted at 2016-11-19 12:00
Hi, Can you post some specs of the videos taken.

Right click the Video file then select properti ...

'if its less than that and you are shooting 4k then its probably a low quality micro SD'

The SD card has no effect at all on the recorded quality, it either records or it doesn't.

Geebax Posted at 2016-11-20 16:58
'if its less than that and you are shooting 4k then its probably a low quality micro SD'

The SD c ...

In a perfect world yes, but as a lot users have found, including myself, there are many shortcomings with micro SD's

C_LUU Posted at 2016-11-21 16:24
In a perfect world yes, but as a lot users have found, including myself, there are many shortcomin ...

What have you found?
I ask because there are a lot of misconceptions about SD cards on this forum.

Geebax Posted at 2016-11-21 00:55
What have you found?
I ask because there are a lot of misconceptions about SD cards on this forum.
...

washed out video, missing frames, missing files, corrupt files, extremely pixilated videos, I have even had all the videos from gopro record with a really blue tinge for no reason at all, then revert to recording fine after formatting SD. I have a number of Lexar, Sandisk and Samsung micro sds that i float around, i only use the lexar ones for 4k or anything requiring high bitrate such as 1080p 120fps. I did notice that there is some new cards on market but havent had a look as the lexar 633 work well for me.

there must be some new developments as i am not aware of any cards able to record at 100mb/s (P4P)?

Nigel_ Posted at 2016-11-20 20:50
"I'm shooting in 4k in D-Log"
Using D-Log is part of the issue, it looses smoothness in the midran ...

Thanks Nigel, This is what I was worried about. Do you think that it's not an issue with the camera then, and everyone will get a similar issue to this because of using 8bit D-Log.

C_LUU Posted at 2016-11-21 17:04
washed out video, missing frames, missing files, corrupt files, extremely pixilated videos, I have ...

The Sandisk Extreme Pro can record 95 Megabytes per second, way fast enough to handle 100 Megabit video. I note that the new Inspire 2 requires miniature SSDs in order to handle the new RAW video modes, it can take two of them plugged in near the batteries.

"washed out video, missing frames, missing files, corrupt files, extremely pixilated videos, I have even had all the videos from gopro record with a really blue tinge for no reason at all, then revert to recording fine after formatting SD. "

In the Phantom, the sensor feeds into a video processing chip, and that chip outputs a scaled down 720p stream to feed back to the RC unit, and the same chip has a complete SD card interface built into it. The digital stream that is recorded has been processed in the vision processor and encoded in H.264, and is then recorded on the SD card. Any problems, such as I have underlined above, are quality issues and are not affected by the quality or speed or otherwise of the SD card. The card is presented with a stream of digital information which it either does or does not record.

Missing frames for example, cannot occur in an MPEG stream. If you are seeing missing frames, it is a problem in the system that is decoding, or replaying the MPEG information, not the system recording it.

If anything goes wrong during the recording, the card simply stops recording, and there can be many reasons for that. The most common one is using a card that does not have the speed rating required, or continuing to record on the SD card after many sequences of copying or deleting of files. Most people do not realise that there are hidden folders and files on the card, and even though you delete the video files, the hidden folders are getting larger and larger, eventually impacting on the ability to record properly.

The best practice is to copy your files off the card after a flying session, then immediately format the card in the aircraft. When you format, all the hidden files are erased and the card is in pristine condition to write again.

C_LUU Posted at 2016-11-21 06:04
washed out video, missing frames, missing files, corrupt files, extremely pixilated videos, I have ...

" there must be some new developments as i am not aware of any cards able to record at 100mb/s (P4P)?"

Any U3 rated card is by definition able to record at twice that speed, the majority of U1 rated and the older Class 10 rated cards will also work at those speeds, it is only a little over the Class 10 rating.

An SD card can't cause "washed out video",  however it is possible but unlikely that the camera could cause it through a fault in the camera that is triggered by the speed of the card.

Geebax Posted at 2016-11-21 09:05
The Sandisk Extreme Pro can record 95 Megabytes per second, way fast enough to handle 100 Megabit v ...

Thanks Geebax. So do you think the colour blocking is because the image processor in my drone is faulty and not processing the image from the sensor correctly? Or am I simply asking too much from the H264 Log file?

Visual Blimp Posted at 2016-11-22 01:47
Thanks Geebax. So do you think the colour blocking is because the image processor in my drone is f ...

My guess is that it is a combination of two things, the use of D-Log and the processing that is being applied. I would suggest trying to use normal non-log output and see what results you get, as Nigel says, it can be troublesome due to the border-line quality the camera produces in log.

Visual Blimp Posted at 2016-11-21 09:02
Thanks Nigel, This is what I was worried about. Do you think that it's not an issue with the camer ...

Yes, I think everyone would get the same issue if using D-Log in those conditions and making the same adjustments in editing.

In general when using 8 bit recordings, it is best to get the exposure, contrast and saturation as close as possible to the desired end result when recording, that way any small adjustments you make in the editor will not show up the imperfections in the compression.  Keep the sharpness setting low as more sharpness uses up the available bitrate and so results in more blockyness, you can add sharpness as the last step in the editor without causing issues.

Only use D-Log with 8 bit video when it is necessary and you can't achieve the same result using the exposure and contrast controls, normally it is not necessary.  With 10 bit video it would be much more useful, but we only have 8 bit on the Phantom and at 4K the compression artefacts are close to being visible even before editing - you don't want to make big adjustments in the editor, especially if you are going to leave it in 4K rather than output 1080 FHD from the editor.

Thanks for your help guys. After plenty more testing I think one of the major factors contributing to the issues I was seeing was using the 'Vibrance' adjustment in After Effects rather than the Saturation setting. I guess this again comes back to 8 bit issue where the Vibrancy adjustment is just trying to pull the colours apart more than the video can support. I have been doing as you suggest though, and trying to only use log when I need the extra range and it does help a lot!

Thanks!!

Mark