A Newb’s questions about video quality, frame rates, hosting platforms etc

Video and Photo Editing
1

I have seen various threads with queries like this but I can’t quite get it all in perspective.

So here I go.

I realise that auto settings (on my DJI Mini 2) can be bettered with some ore experience, some ND filters and some experimenting in ‘Pro’ mode.

But my understanding of that is, it gives you more flexibility in how you want the image to appear from an exposure aspect but that it allows you to adjust frames rates, shutter speed and ISO within a rule called the 180 rule which can make motion blur more natural.

I am yet to really understand the 180 rule and as such it is not particularly a question from me, especially as I don’t have any filters yet. I mention it more to show the experienced people here what I understand so far. So if it’s possible I’d like to park all that for another day and get back to the other things I’m noticing.

Firstly,

Flying in cine mode and being as gentle as I know how on the sticks in auto settings, I have tried 24, 25,30 FPS in 4K. Grabbing the footage from the SD card and into iMovie I believe I see the least jitter when panning horizons at 30 FPS. Thats contrary to most advice I’ve seen. As 24 FPS seems to be recommended for cinematic shooting, most advice comes from that concept but I think the reality is, just because I’m panning in cine mode as slowly as I can my footage does not truly qualify as Cinematic. Here I believe there is misconception in the 24 FPS advise. Does it sound reasonable that 30 FPS in 4K (in the absence of ND filters and ‘pro’ mode experience) might do a better job than 24 or 25?

Secondly,

Taking some nice footage in to my editing tool (iMovie only I’m afraid - suggestions welcome) the yaw movements look smooth enough. I can choose to export from there in many resolutions from 4K downward. Thats with 4K chosen, why choose less? And once complete Qucktime (Apples default player) increases the jitter of the panned horizon. So I’ve now moved from thinking the tiny bit of jitter I had was on a par with many bits of footage I see from experienced ‘Dronies’ to much more irritating jitter.

Hmmmm……Is that a fault of iMovie, QuickTime or both ?

So I decided to export one at 1080p and things generally improve.

Third,

I have uploaded to you tube (I would post here and I’m happy to provide a link to those interested but I have kept it private and the reason is simply that the backing track will almost certainly breach copy right and I wasn’t putting up there but decided I would test it. If I upload publicly I will have to choose something else in future.

Now the first thing is, 720p is the max resolution I can upload on my free account as far as I’m aware.

I have seen some posts recommending Vimeo so I’ll chest that out. But by now I’ve been through so much that I have lost sight of the amount of jitter. In fact to add to that some gimbal yaw in the down direction looks quite bad (I need to go back and check that I thought the original was OK and I certainly hope so).

My thoughts,

I’m getting to the point where I think I might be better off taking footage in 1080p?

That way I’ll have more SD card space, less reduction during processing (Which ends up in QuickTime) and less reduction if I upload to you tube. Should all that help the softwares mentioned deal with with the jitter or does it simply mean as I only start with 1080p quality from the drone, that the result will be worse than if I started with 4K?

Or put another way, do you only truly benefit from 4K by taking the settings out of auto mode, slapping on filters, having top notch editing software with strong processing performance and paid subscriptions for higher quality uploads to You tube or competitors?

Having got that far I know it will also depend on what the viewers screen is capable of.

I’m happy enough to not put super fuel into a ford fiesta but I’d also like to know if I’m missing the point and could gain more from 4K. Could there be something wrong with the drone?

Please pm me if you want the link to the 9 minutes of footage.

And thank you if you made it to the end of this very long read.

3 Likes
2

As far as I’m aware there isn’t a resolution limit on Youtube - I certainly don’t pay for my account ( Goldie644 ) and regularly upload videos in 4K60 - it just takes Youtube a bit longer to process so it publishes lower resolution options first while still processing the HD/4K versions

With my Mini 2 I generally video in 2.7K60 - as you’ve already noticed yawing at 30fps creates very noticeable issues, though oddly panning up or down isn’t so bad - probably something to do with the way the image is scanned by the sensor. 2.7K is a very good halfway step between 1080p and 4K.

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@MartG1960
Thanks,
Thats interesting about you tube resolution! I’ll watch and wait. The best I’ll get for this now is 1080p.
Another good point about 2.7K60, I didn’t think of that and for sure it will be the next logical step down from 4K.
I’ve just taken a look at ‘A flight over the Wyre’ and no such issue there then :+1: Excellent I’m going back for more in a moment.
How do you get from SD card to you tube?

4

I always use 2.7k at 60fps. Far more options in post editing. Who’s going to notice anyway, care even?

SD card into card reader, straight into the back of the iMac. Import into Filmora X for editing and then export either directly to YouTube or to the Mac and then YouTube.

Phil

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5

Ha ha yes …well I guess no one if there aren’t jittery panning bits.

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Pop the SD card out, card reader to transfer it to PC, edit with Adobe Elements, then upload to Youtube.

BTW The ‘Flight over Wyre’ video was shot with an Air 2 at 4K60

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Just to note, as I have uploaded a fair few non-drone videos to YT over the years, the video compression will hit the quality a bit but still look very good. It’s why some people offer a download via their own websites for quality comparisons, especially of video or photographic work.

Also with regards private videos and backtracks, YT when processing will still check for copyright audio and mute the audio if necessary on most occasion, even if it’s set to Private.
Plenty of copyright-free audio out there to use.

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8

I’ve used GoPro cameras for a couple of years, on a car and a bike, and moving footage from these cameras looks jittery when crunched by YouTube. I found that 2.7k 60 was a good setting to get rid of most of the jitters.

So when I bought my Drone a couple of months ago, that’s the resolution I use.
4K is obviously going to be better, but it’s a nightmare to edit and the space it takes up just isn’t worth it for what I do.

It depends on how long your video is and how much editing is needed, and how well specified your PC is.

Viewers like the scenery, and the story a video tells, most don’t even notice what we notice and worry about.

2 Likes
9

Re the frame rate, I always had “jitter” on pans using 24fps or 25fps. Changed to 30fps and the “jitter” went away. Put it down to the playback refresh rate of the computer being 60hz.

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10

Me too, I noticed the juddering whatever the playback device.
I just cant get the results I want with 24/25fps, I switched to 30fps and made a big difference to me.

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11

Thanks Rafter for sharing your finding, being consistent with mine.

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@Fad_Flyer, I’ve never flown a DJI drone but I’ll pass on a couple of observations, for what they’re worth, based on my Autel Evo and digital imaging experience.

The big issue, imho, is the capability of current SD card technology to faithfully record whatever you ask it to. I believe that the technology is stretched even at 4K/30fps and that anything above that results in degradation of the footage.

When you consider how much data is being recorded at 4K/60fps or 6K or 8K, it should need a supercomputer to capture it faithfully and no battery powered drone can hope to do so – even though the industry wants us to upgrade, spend more and leads us to believe that we can achieve the impossible.

Even at 1080p, the drone relies on compression algorithms to capture everything with minimal loss of data. But you still don’t end up with the quality of image that the sensor is optically capable of.

Until the next generation of memory cards comes along, I stick to 2K max for my drone video - and I usually upload it to Youtube at 1080p because that’s all the majority of folk can play.

Panning/yawing is especially difficult to process within the drone since compression algorithms work best when the pixel changes between one frame and the next are minimal. By panning, we force excessive frame-to-frame pixel changes down the pipe and that can lead to dropped frames/judder. You can minimise this risk by panning as slowly as you can. (Even Hollywood digital studio cameras have to follow rules to obtain smooth pans – the pro operators reckon it should take at least 7 seconds for an object to move from one side of the screen to the other in a pan.) And if memory cards have to drop data in order to capture 4K at 60fps then you may actually lose more in a 60fps pan than a 30fps one.

To minimise Youtube’s processing curse, you need to eliminate all unnecessary processing steps before you upload your video. If you edit or colour grade, be sure to save your video at the highest possible quality before uploading it. In iMovie, save your video using File->Quality->Best (ProRes) or Custom and then upload the resulting very large file to Youtube. If you introduce an unnecessary processing/compression stage by saving in any other format then Youtube will compound your artifacts with its own and the the result on screen will be sub-optimal.

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@evonne
Thank you for taking the time to reply in such depth.
As they say, every day is a school day and for me, filming and photography take some acquired knowledge especially when you are also negotiating drone rules, obstacles and skill for manoeuvres that are all new territory.
The SD card I have came recommended by DJI but I get that. it will have limitations like the ones you point out.
I have this from a reputable store
sd

On that basis and they fact that 1080p is still very capable and accepted especially on smaller screens I will give the drone and the card less donkey work to do and see what happens.
I also haven’t got slow panning nailed particularly well so indeed their is that to factor in.
I’ll also be mindful of your thoughts to upload the highest res to You Tube even though the source footage will have been captured at a lower res.
Thanks again.

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That card is as good as any, the key parameters being U3 and V30 - and assuming your drone’s bitrate is 100Mbps or greater (6-8K drones now typically boast 120Mbps). But this chart indicates that this card is stretched at 4K. So if you’re not happy with your 4K footage, you might try shooting in HEVC (H.265) instead of the standard H.264 since H.265 produces similar quality to H.264 but at significantly smaller file sizes.

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15

A very brief comment concerning the basis for judgement over the quality of the images captured by our drones.

As @evonne says, it’s a bit of a miracle to get domestic computers (and mini computers like drones) to record and display 4K footage at all - compromises (i.e. compression) have to be made. Therefore, before checking the quality of the drone’s ability to pan smoothly, or your card’s ability to handle the data, it may be worthwhile to export your footage at a lower resolution (for example, 4K → HD, or HD → SD) and see if this plays smoothly on your computer? If so, it might suggest that your computer is responsible for the juddering/stuttering in presenting the film to you, rather than an inherent problem with the recording, the resolution or the drone?

[Compression is an absolute requirement for digital storage and display. One 4K frame of 3840x2160 pixels, each requiring 4 bytes of colour and transparency information, would require 829440000 bytes (790Mb) for one second of a 4K movie at 25fps, and one minute would require 46G of storage, and a small supercomputer to display it in real time. However, my 128G SanDisk card, which is just like @Fad_Flyer’s, takes ~1G for a 60s drone shot from a Mavic Air, and my 4GHz computer can play it in real time.
Hoping I haven’t made some obvious calculation errors here!]

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I’ve only done a couple of lfights with the Mini 2 and had found whilst the original 4K/29.97fps files played smoothly on the computer, the edited files - exported to the same spec. - were unacceptably jittery.

The solution was to export at 59.94fps (using Corel VideoStudio) and the footage is now excellent and looks fantastic played on the TV as well.

The higher export frame rate made very little difference to the file size; 180Mb only became 186Mb, as there is no extra picture infromation.

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