Mavic Pro: why DJI doesn't fix this huge flickering/compression problem?

[deadwing]

By the way I got in contact with DJI suggesting a future update where we can choose between 'smaller file size' (as it is now so smaller resolution is smaller file/bandwidth) OR Maximum Quality, where the Mavic uses 60mbps as the encoding bandwidth quality at ALL resolutions.

That way someone could choose to encode al lower resolution to get more frame/by/frame quality or higher ones if they like it more, but would give us much more choice.

Is there a way we can ask for it and so if they receive from more customers maybe they'll do it quickly? Is far from difficult to do, actually I think for them would be straightforward to do it.

 

[Pathogen]

also considering that shooting in 2.7k or even higher would help anyway as I have then to convert it 1080.

I was actually going to suggest shooting at 4K, because then you get +60megabit recordings.

 

[Kilrah]

And more color information due to the way h.264 works with 4:2:0 chroma subsampling. Shooting 1080 that information is lost, shooting 4K the same relative amount if info is lost in a frame but since the frame is 4x bigger once resized to 1080 you get a fully defined image to work on.

 

[deadwing]

Shooting at 4k from all my tests is much worse, as 60mbps are way not enough for any decent 4k footage recording. And 1080 is equally a waste as it's as well using too small bandwidth. As I said from my first tests, shooting at 4k is good for simple scenery or far objects, but for more demanding scenes, or more expert eye or usage that is not Youtube on a computer screen, it's just not working. Basically to obtain footage where the GOP is not flickering you have to go -3 sharpness if in 4k, while in 2k you can go with a -2 (that is much better in details).

Obviously if someone needs the 4k output then tey have no choice (but I think in that situation you need something more 'pro' than a Mavic). But if the in the end you film for HD and/or internet, as many others said the best real quality is at 2k with Mavic, and from my findings is true and even better quality is at 24fps.

And sharpness -1 for simple scenery and -2 for more complex one.

And I agree that shooting 1080 on Mavic is unreasonably poor quality, it seems they used a very 'mathematical' approach cutting 35% of bandwidth down for each resolution, and the middle one (2k) that is a sort of sweet spot.

I think would be a half revolution if they could simply enable a 'Full Quality' mode that allows us to use 60mbps no matter what resolution we use, it would mean much more choice and for example amazingly clean 1080 footage and a much better 2k...they said they'll suggest it to their team, but I highly doubt anything will happen unless we all ask for it

 

[deadwing]

I think I forgot to include the Youtube proof...I already posted original footage directly from Mavic showing the flicker, then I posted another footage shooting at 2k with sharpness -2 at 30fps showing no flickering whatsoever (filming in 4k or bringing sharpness to -1 made flicker appear again).

As I said doing more tests I saw that shooting at 24fps allows almost always to recover a step up of sharpness, below is 2k at 24fps with sharpness -1...no flickering in the shadows or pulsing details etc despite the demanding scene (all detailed greenery, half of which moving and half almost still, strong lights and shadows nearby etc.):

Filming in 4k is possible at 24fps without flickering but keeping sharpness at -2, that means that actually the 2k with sharpness at -1 is more sharp! Filming in 2k and bringing sharpness up to +0 makes as well flickering appear again.

So the choice for me will be 2k with -2 sharpness if I need 30fps (almost never luckily), and 2k with sharpness at -1 when I can shoot at 24fps (almost always!), and using the ND32 makes it easy to keep shutter at 1/50 or 1/60 and makes the 24fps natively ready for film.

If you have similar scenery to film try yourself and post here results, as I said the classic countless 'high and slow and far away' scenes that everyone does with the Mavic are more forgiving (but to me much less interesting), but if you try shooting similar scene and set of mine, you should start seeing clearly where the sharpness/GOP problem appears and what are the settings to obtain the best filmic/cinematic quality.

PS: if you check the number of videos I did between my first post and this one, you can see I was in that field for a very long time...I think I did the most scientific and repeatable (and picky!) test I could do...and I feel I finally got to know the Mavic limits and how to get the best out of it for some professional usage.

 

[Pathogen]

Well deadwing you have inspired me to do some maths now, thanks for that.

btw when you speak of flickering are you talking about aliasing?

Also, when I switched from -1 sharpness to +1 sharpness, I swore I noticed that suddenly the foliage didn't looked grotesquely smeared any more. Am I mistaken?

EDIT MATHS:

...resolution..pixels....bits.......bits/pixel(pre).
4K.4096x2160...8847360...60000000....6.8
3K.2720x1530...4161600...45000000...10.8
2K.1920x1080...2073600...25000000...12.1
1K..1280x720....921600...8300000.....9.0

So 1920x1080 offers the highest bitrate per pixel, while obviously 4096x2160 offers highest bits per inch. Since I have no use for 4K as a final product, and only require 2K at the very highest, I am now wondering if there is any reason at all to record in 4K except for having the option to do digital zoom/pan/frame in post, although that is a huge reason on its own.

 

[Oglo]

Deadwing your effort is greatly appreciated.

I went through similar long winded tests on my Osmo and tried cataloging the results. It certainly was time consuming. I have also tried many settings on the Mavic and totally follow your logic/methodology.
I was eventually sold on 2.7k with +1, 0, 0. with no colour profile. I was shooting lots of foliage & grass at 0,0,0. and couldn't believe the "grotesque" smearing. (I had picked 2.7k to match Osmo footage on my timelines).
I monitor shots on a couple of high quality (consumer)UHD screens, and a couple of Dell hi-spec'd HD screens. I decided to re-look at 4k (UHD) and have now decided that it does give me better detail so locked in 4k 1,0,0 norm (no colour profile).
It does look "crisp" because of the sharpening but I find that as most of my finished products are HD, the final re-sizing down (and associated anti-aliasing) takes care of the over crispness but also gives an amazing "full of detail" feel. I prefer this to the smeary look. This is all subjective obviously.
I too would like to be able to choose a quality setting as the GOP problem rears it's ugly head as you have outlined. As you correctly identified the strobing seems to appear on fast moving areas where the algorithm struggles to keep up. Interesting to watch the effect on high detail grass from when it's static showing lots of image detail to when its moving, (done at high shutter rates so that motion blur isnt a factor) showing the inadequacies of the compression and GOP effect. I suspect that DJI has no control over the compression settings as these are dictated by the h.264 encoding chip they use - on the Osmo I think it was a Texas Instruments chip with everything baked in.

One part of your process that doesn't work for me in my observations is the use of dlog or cine-like. With a 4.2.0 sensor and a heavy compression (less than 60mbps) trying to increase dynamic range with an already 'dynamic range limited' format is asking too much of it. My limited tests bore this out on my footage. As stated by many other more "pro" people than I, absolutely maximising and monitoring the exposure (via the histogram) is the single most important tool for maximising dynamic range.
I shoot in 25fps. Edit&grade in Davinci Resolve .

Once again Deadwing, thank you for your insights, please do continue to keep us updated, they are a valuable contribution here.
☺

 

[deadwing]

Cheers guys, i'm glad to see everyone is concerned (with slightly different and personal preferences) about these drones sensors...to be honest, knowing a thing or two about compression, I do think they could solve very simply enabling the max bandwidth available (60mbps) for all resolutions, a so called HD mode, as in that way everyone could simply choose the best compromise between single frames quality and resolution.

Anyway to reply to Pathogen, flickering I talk about is not aliasing, is the GOP artifacts and so called inter frame flicker (that happens about 3 times each second), that's very evident as when Mavic uses sharpening it can use it only on the key frames (one every 8!), and so it means the more you sharpen (or the more details you want to get natively) the worse it is, as the other frames cannot get those details in complex scenes (for the limited bandwidth), hence the 'flickering' on details and shadows.

The smearing you guys talk about I think is there not because we don't use sharpness, but because the small sensor of the Mavic really cannot get details (in the shadows in particular). Now using sharpening is the way to overcome it, but while doing it on the Mavic means doing it every 8 frames, if I do it instead in production working on a uniform (although less sharp) footage then it means I can have much better control of sharpness because in edit we can apply sharpness to ALL the frames. This means that to work we need the most uniform original video, the 'raw' one (just to say), and that means disabling completely any sharpening done by the Mavic (that is limited understandably) and instead do it in post.

By the way...the famous video of The Film Poets showing smearing and +1 sharpening as a solution...I don't think everyone realises that they actually sell profiles for Neat Video to reduce flickering with sharpness +1 (incidentally what they suggest to use..)

Mavic De-Flicker Preset & Profile for Neat Video - ISO 100

And here in a non public video they tell you that THERE'S FLICKER at +1, and they sell the profiles (!) to get rid of it...#justsaying

I do think my approach is instead more RAW footage approach...don't point at getting the sharpest/final footage from the Mavic as it uses digital sharpening to overcome its limitations..try instead to get the most UNIFORM and neutral material and adjust it in production, where you can apply better sharpness. For me it means 2k -1 sharpness at 24fps, but results can change for everyone based on how much their eyes see the defects (I see it now in almost every Mavic footage online), and on the shooting situation.

And about Neat Video....if you look around on Youtube at tutorials how to use to remove flicker...the final result is so 'smoothed out' with a clear heavy denoise that is worse than the flickering it was tryng to adjust, in my opinion

 

[Oglo]

Great. I'm going to re-look at my footage keeping in mind all you've pointed out.
Thanks.

 

[deadwing]

Great. I'm going to re-look at my footage keeping in mind all you've pointed out.
Thanks.

Well if your eye cannot detect any problem be happy as it means is all right for you

Personally I'm used to tweak encoders to the last bit for professional blu-ray publications so that flickering was the first thing I noticed in mine, and checking Youtube footage with attention and in HD I started noticing the same problem everywhere apart from heavily denoised or very simple videos (notice that 90% of them are just from high up in the sky where little to none fine detail is moving randomly on screen).

I wish we had RAW but is not possible on such small and 'cheap' device, BUT I found eventually that following the rules or raw postprocessing works best: to get as plain and dynamic footage as possible (dlog works perfectly if you expose correctly in the last third of histogram), and most of all that is better to get a soft image and sharpen it carefully later than getting a digitally sharpened image to denoise it later.

Simply because denoising is a destructive process in itself (no matter what), sharpening is the opposite as it tries only to add information (although it can be overdone as well!). And computers are much better at guessing what to add to make human eye perceive something as sharp than deleting information.

Also (but this is more personal) I think the best footage is cinematic, and cinematic footage is never sharpened, is rather soft usually as it's more pleasant to the human eye...sharpening is like high frequencies in music..when speakers or headphones have too much 'details' or 'high frequencies' (same concept as fine sharpening) they are fatiguing, and in fact the most professional ones are usually defined as 'warm' and 'natural'.

The Mavic has a sensor with its limits, is small and so it needs lots of light in the shadows (or it is smeared), but that is easy to achieve with an ND filter, using dlog and exposing always for the last third of the histogram (without burning highlights). All this in 2k -1 sharpening at 24fps produces in my opinion and tests footage that only needs grading and no denoising/deflickering or what not

If anyone else wants to try similar footage to mine and see what they can perceive in terms of ideal resolution and settings, would be nice to compare

And if we can think at a way to ask DJI to implement a 'high quality' setting to have the full 60mbps at any resolution would be fantastic!

 

[deadwing]

Talking about others' videos, this was always one I particularly like as it's very simple and well made (although we don't know what sharpening settings were used but I assume 0 from what I see):

After minute 1:19 you can see the full 4k, 2k and HD...and the 4k is clearly pulsating and flickering on the details (even more evident if watched in a small window!), while the 2k doesn't show this at all, and the HD (as we sadly know) is just crap

Another I always loved was this one:

and again just see at the water and then overall image of the opening scene...in this one the flickering is even more evident in terms of shadows/lights (and how the details of waves 'flicker' as well as they move from one key frame to the other and are instead averaged in the middle 8 frames!). Here is more a shadows/light flicker because is not a well and uniformly lit scene as the previous video (that presented another challenge, the green foliage/trees).

 

[raybanner]

I did all the tests you are just doing long time ago. The GOP issue was annoying me to a state, where i wanted to stop using the mavic. I tried a lot of settings and settled with 2.7k and +1 on sharpness and working with neat video.

I did this small comparison a while ago. No neat video used in this demo. 4k = more flickering/pulsing.

 

[deadwing]

I did all the tests you are just doing long time ago. The GOP issue was annoying me to a state, where i wanted to stop using the mavic. I tried a lot of settings and settled with 2.7k and +1 on sharpness and working with neat video.

I did this small comparison a while ago. No neat video used in this demo. 4k = more flickering/pulsing.

Yes thanks for your video, infact is one of the very few (if any else) I saw at start and that was confirming what I suspected!

I totally agree with you, the annoying part is that if DJI would give us 60mbps in 2k we would probably solve good part of this problem!

Yes using 2k with sharpness +1 and Neat Video gives me similar results to using -1 without Neat Video...I did compare these two a lot, all the times I go from -1 to +1 NV I think "maybe is a bit sharper", but when I go then back to native -1 one I always think "aah much more natural and pleasant".

So I suppose is a matter of personal preference between these two as they are similar, probably for me the other problem is that I can't stand how slow is NV and so I end up disabling any sharpening in Mavic and enabling a tad of very small scale (0.5 to 1 radius) edge sharpening if needed, that is almost istantaneous.

Again thanks for your video, is PERFECT showing the compression flicker problem

 

[prometeo]

Hello all

I had a Chat with Arnel in DJI. Explained the problem we discussed here.
I was clear the methods I'm using to make the Mavic's footage OK (Neat Video, Film Poets, all Manual, By case settings...) Showed D-Log film with 8 frames flickering.
He suggested sending an email to the service department with the problem I describe.
They sent me an RMA. The Mavic is on its way to Los Cerritos.
PS: I don't have high expectations of this trip to the mothership, but surely I hope at least it serves to get closer to software update fixes that compensate for the reality on the Mavic's camera.

 

[Pathogen]

Anyway to reply to Pathogen, flickering I talk about is not aliasing, is the GOP artifacts and so called inter frame flicker (that happens about 3 times each second)

Ah yes I see it now. Without testing as I have no +1 sharp footage handy, is this something a temporal smoother could deal with usefully?

 

[Raymondo]

Difficult to tell from your first video. There is a lot of compression blocking, possibly due to the upload recompressing. This clip I shot was a test for camera movement in a short film drama. Excuse the jerky flight as it was the first take. However, I couldn't see the same symptoms that you have. I shoot at 25fps, 50th shutter (for PAL display) and -1 sharpness.

 

[Raymondo]

BTW the move will be following a couple of actors and a dog.

 

[Pathogen]

However, I couldn't see the same symptoms that you have.

What we are looking at is the 8 frame GOP artifact. Frame step through a DJI recording and notice that every 8th frame, 'something' happens. It is something that a lot of people would have to have pointed out (like me) to ever notice. People that work with video professionally tend to see things nobody else notices. I learned that when repeatedly explaining bad telecine removal examples to folks. While people don't notice consciously, on a subconscious level I think it gives them the feeling that what they are looking at is not professional.

4k 1,0,0 norm (no colour profile)...most of my finished products are HD

I am seeing things this way as well, and would go so far as to say, the Mavic is not 4K video camera as it currently exists, but can produce fantastic 2K video. Thank-you also by the way for the exposure advice. I assume it gets easier with practice?

 

[fnf]

Yes thanks for your video, infact is one of the very few (if any else) I saw at start and that was confirming what I suspected!

I totally agree with you, the annoying part is that if DJI would give us 60mbps in 2k we would probably solve good part of this problem!

Yes using 2k with sharpness +1 and Neat Video gives me similar results to using -1 without Neat Video...I did compare these two a lot, all the times I go from -1 to +1 NV I think "maybe is a bit sharper", but when I go then back to native -1 one I always think "aah much more natural and pleasant".

So I suppose is a matter of personal preference between these two as they are similar, probably for me the other problem is that I can't stand how slow is NV and so I end up disabling any sharpening in Mavic and enabling a tad of very small scale (0.5 to 1 radius) edge sharpening if needed, that is almost istantaneous.

Again thanks for your video, is PERFECT showing the compression flicker problem

I'm an experienced photographer but have just recently dipped my toes into aerial videography so I won't dispute your knowledge but am stating my opinions.

As many others, I've chosen 2.7K@30fps D-Log +1, 0, 0 as a ideal setting for the Mavic. The colour and saturation are set to 0 because I read that the low bit-rate, coupled with the 8-bit YUV 4:2:0 encoding makes it very hard to stretch the histogram in post because the subtle tonal changes will be compressed to the same value, leading to banding in areas of similar tones e.g., the sky.
The usual practice of shooting at low saturation/contrast to preserve as much dynamic range in log footage or to match the JPEG histogram as close as possible to the RAW capture therefore doesn't apply very well to the Mavic it seems.

In terms of the sharpness setting, I could say that I have seen the flickering issue at +1 on some of my footage that has large moving clouds or the ocean waves. I do not have this issue that often though, there is no problem shooting sunrise/sunset scenes with high contrast as long as the scene doesn't have areas with subtle tonal changes.
In my personal tests, I have found that +1 gives me the best image quality, anything above that doesn't make much of a difference, anything below that makes the footage a complete mush, despite that there was plenty of light.

For this reason, I'm inclined to believe that the Mavic applies noise reduction on any sharpness setting at and below 0, which is an irreversible process. I have uploaded framegrabs of the test videos here: Dropbox - Mavic Pro sharpness settings comparison . They were shot at 24fps and 30fps at all sharpness settings.

Here is a photo combining the 3 sharpness settings at 0, +1 and -2 @24fps for comparison:


Here it is enlarged 2.5x:


The loss of details at sharpness settings 0 and -2 is apparent, I have tried to sharpen these but I found it impossible to recover the details.

 

[Oglo]

fnf your sharpness tests match with my observations, viewing video footage on large UHD screens, and within Davinci viewing on HD screens.
As Deadwing has been mentioning, we are all trying to get the cleanest high resolution look without the dreaded GOP strobes. One seems to work against the other in some situations. He rightly surmised when viewing those lovely high slow moving shots the compression pulsing artifacts don't show.
It's a hard one to know what to lock in on. I've had a lifetime of concentrating on creative content but also having to put huge effort into quality control. I was hoping that finally in this high tech era we could just concentrate on the content and the quality issues would be a thing of the past - not there yet unfortunately. It still amazes me what we can get out of something that fits in my hand - I used to have crews of 15 or so and trucks, helicopters, heavy 35mm cameras to get the same quality.
☺