Mavo LF : banding / distorted footage

[Gualbert]

Hi Martin, welcome to the forum. I mentioned the low ISO and HS to Steven previously but after testing that myself now it is clear is bears no influence on the banding issue. I have to agree with you that, although the banding is less visible in 6K, it is still noticeable unfortunately. I wouldn’t worry too much as my experience with KineTeam they usually address and correct issues once they have been validated. In the other hand, it is only affecting pseudo-monochromatic chunks of the picture, like the flat flat surfaces and the shallow DoF areas. It is a very weird thing, looks similar to when you compress an image and the portions that are made of the same colour get the stereotypical banding from compression to represent the shades gradation. Anyhow, I think we should keep sharing the info with the KineTeam, also may help if posting in the Kine Service Facebook page (not the standard non-official as that other one has like ~10K users and most of them are trolls that don’t even own a camera).

[Adam Werton]

It shouldnt have anything to do with how you shot it. What’s your current firmware version?

And i know it sounds weird, but can you use something to convert it again into Prores?

Or if you dont mind send me a copy of the original footage and i’ll see if i can fix it.

[Adam Werton]

As long as your shadow isnt crazily noised, it’s not the FPN issue they talked about. I took a look at their footage a while back, you can definitely see something is wrong with it, it’s got crazy wavy noises even under direct sunlight. Jerome sent the camera back to china and recalibrated them and it was solved.

[Steven]

Hi Adam, I received my camera with firmware 6.2 installed & never touched it until today I installed some new firmware Kinefinity send me.

You can find some original footage in earlier posts (dropbox links). My cam is at use atm, tomorrow I’ll run some more tests and let ya’ll know what happend.

[Gualbert]

Adam, this is nothing the new firmware will do something about. As I said in previous post I updated to the latest as I was on 6202 and that didn’t do anything for banding. From my perspective I don’t see it as a deal breaker but I am not a film maker. The issue is when you apply Neutral Kine LUT and export in a format let’s say H.264 the banding becomes unbearably noticeable. Again, please read the earlier post so you can understand when it happens and how to notice it. It doesn’t happen in all situations. There are also some examples Steven was kind enough to upload. I downloaded his clips and played with them in Davinci, the one with the seminar is probably the worst with very noticeable banding. I have also been able to duplicate this issue. I haven’t brought this to the KineCameras facebook as there are like ~10K users there and most of them are trolls or don’t own the camera. But this is definitely something Kine needs to check and address at some point. As I have mentioned before, it’s impact is worse the higher the downsampling is (i.e. FF 3K is the worse of them all). At the beginning I thought it could be just the way the downsampling was performed but 6K also has the issue, almost imperceptible but it’s there nevertheless.

[Gualbert]

…forgot to mention in response to your earlier comment, we know that this is not FPN as I mentioned before. It is banding, in fact it looks like gradation banding on single color surfaces due to compression. No idea if you still have your T4K or if you traded for MLF, but if you can get your hands on a MLF I can tell you exactly how to duplicate the issue. Cheers!

[Steven]

Some quick notes before I start testing today:

* regarding the firmware, they send me some unreleased new firmware 6.203. We’ll see what happens.

* So Gaulbert, if you were able to simulate the banding, does this mean that every Mavo has this issue ?

* Should I put the test I did earlier (6k step by step aperture online @ dropbox) so we can see at what aperture setting it’s unnoticeable ?

 

[Gualbert]

Actually Steven, there is a favor you can help with as my Mac is very old and cannot handle 6K files in Resolve. If you have the time here is the test I would like to see. Try to replicate the issue in cDNG instead of ProRes, once you get a wall surface where you feel pretty confident you can duplicate the issue then switch to cDNG without changing anything else, record 4-6 secs then try and see if you can notice banding after you colour correct and export your 4-6 secs into H.264. I have noticed that even my ProRes 6k has some banding after exporting to H.264 in Resolve… Like the clip you shared with the seminar speaker (but that one was 3K)…

[Steven]

Ok Gaulbert, let me see what I can do next. I already did this one before you replied, at 1st I thought it was gone but when I changed the shot & used some shallow unsharp part of my desk I saw it appearing on my Kinemon. So I suppose it’ll be present on these 2. I changed aperture settings one step to check at what aperture settings it disappears. (so far we can conclude, these banding effect appears at flat white/yellow toned unsharp parts of an image) … I’m not sure if this unreleased firmware install had any influence (feel free to check my test footage in the dropbox folder below).

https://www.dropbox.com/sh/63vdgl2ur8kx502/AAAa0qbrc1dtnzP3Od9ZRhiFa?dl=0

TBC

[Gualbert]

Cool! In the meantime can you check this one? Please let me know if you can still see banding in this clip (your original seminar clip): https://www.dropbox.com/s/t8v2renmrp0p4bh/steven_hevc.mov?dl=0

 

[Steven]

Wow Gaulbert nice ! I can’t see any banding anymore, how did you proces this ? Did all this magic happen in Davinci Resolve ? Thanks man, at least I can send you all my footage when I return from South America next month 😉

[Gualbert]

Damn it really? I will feel so stupid if this is really the “issue”… 🙁 I have spent so much time on this and all I got is a lousy hypothesis… seems like it is the compression… I didn’t do anything to your clip other than add a serial node. Second node added the Neutral KineM. first node adjusted mild colour temp and highlight to taste, nothing else… then the real thing was while exporting, I used HEVC not H.264, seems like unless you export using same ProRes or HEVC the banding becomes apparent for some strange reason… Sorry I cannot explain this further as I am trying to understand it myself. At least you will have a “work around” for your big gig in 10 days… Still, I would like to understand the “science” behind the “perceived” banding…

[Steven]

– FINAL UPDATE – just got some closure from Kinefinity. The banding issue is actually a known issue of the Prores422 codec and has nothing to do with Kinefinity. If you want to avoid it you should shoot at Prores4444 (or ofc KineRaw). We’ve done a test at ProRes 4444 6K and the banding was only visible on the KineMon not on a big monitor. Everything seems smooth as it should be, the result can be found here https://www.dropbox.com/sh/b5zz9u4g4mvy9rt/AADPP7GO9kMDv-exCGEIGW7wa?dl=0

 

Here’s some info about the ProRes422 banding problem in skies, white walls & skin tones http://www.reduser.net/forum/archive/index.php/t-25238.html

[Gualbert]

Interesting! Well, now we also know how to mitigate the banding, just export HEVC 10-Bits 😉

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