I’ve made some progress understanding factors beyond Litchi software that affect video quality. Turns out that Windows, the computer it’s running on, and the display device all play a role in jerks and other undesirable video artifacts. This is in addition to the other obvious factors, like the drone you’re flying, the DJI yaw and gimbal rates and smoothness settings, the DJI Fly-set camera resolution and frame rate settings, and, yes, the Litchi mission you have designed.
Cutting to the chase a bit, I’ve gotten a very good reference 4K/30 fps video created by a simple, but stressing Litchi waypoint mission, and I’ve watched that video using various combinations of equipment that affect the quality, as displayed. My equipment is as follows:
(1) DJI Mini2 drone with a SanDisk Extreme 32Gb
(2) Two Windows 11 laptops:
Lenovo “Gaming Laptop” with an nVidia GeForce GTX 1660TI card
LG Core i5 with Intel Iris Xe graphics.
(4) Four displays:
LG 77" 4K OLED TV, 2 years old
LG 43" 4K LED, (new, and just $259 these days)
Samsung 65" 4K Q8 Searies, 4 years old
Samsung 24" 1080p, about 8years old.
(5) An old inferior generic HDMI cable, and a nice new one that made a difference.
Basically, all the 4K displays with either laptop rendered perfectly, AS LONG AS WINDOWS 11 WAS CONFIGURED CORRECTLY.
Perhaps you perceive a bit of frustration I had when I learned that the default settings for W11 are designed to save energy in the laptops, and not to maximize video performance. And W11 does not automatically detect proper settings over HDMI for TVs–you must do that manually.
I can fill in some details on this subject if anyone is interested…
So,
I’m curious what the correct settings for Windows 11 (or 10) are.
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Let me first point out that I got the very best results on my 4K TVs if I set my Mini’s camera to 4K, 30 fps, the highest resolution and frame rate it could be set to. Anything else at lower resolution gave artifacts no matter what frame rate I tried. And if you take the microSD card out of the drone and put it in a USB adaptor, and then insert that directly into any of the 4K TVs I have, they played perfectly. The old 1080p TV was pretty awful. And if I loaded the file onto my Asustor NAS, then any of the media servers running on the NAS played over my LAN/WiFi-connected TVs perfectly.
My surprise came when I tried to play the same file on my computers, connected to the TVs by HDMI. I saw significant artifacts that looked a bit like a jerky flight, but I knew better. I changed the default app for .MP4 files to “Movies & TV” instead of “Media Player” and things seemed a little better, but not perfect (Settings>>Apps>>Default Apps>>Movies&TV and scroll to .MP4). Also, in Settings>>Apps>>Video Playback, make sure “process video…to enhance it…” is on. I think I was getting occasional “frame drops” during playback, probably due to graphics processing overload.
The solution for my LG using just Intel Iris graphics was to turn off the LG screen and just run the TV (Right click anywhere on the desktop>>Display Settings and change to “Display on Screen 2 only”), The Lenovo with nVidia graphics was a lot more complicated. Basically, right click the screen>>Display Settings and select the TV display. Then scroll down and visit each and every topic and make the obvious changes. Be sure "Movies & TV>>Options is set to “High Performance” and save it.
Big subject, and I didn’t cover it all, but hope this is a good start for you.
While, I suppose, default applications is technically a windows setting, I was expecting to hear something about an actual setting.
You mentioned frame rate. One cause of “jerky” video is a mismatch between the video’s frame rate and the refresh rate of the playback device. If, for example, your video has a frame rate of 24 FPS and your computer monitor has a refresh rate of 60 Hz, mapping 24 FPS to 60 Hz will results in some frames being duplicated which results in less than smooth video playback. If the desired playback device is a computer monitor or TV, most of these have a refresh rate of 60 Hz (or greater). Therefore, 30 or 60 FPS video will be the best choice for recording. Using either 25 or 50 FPS was necessary when older analog displays were used to display the video in countries that have 50 Hz electricity. Modern monitors are not locked to the frequency of the provided electricity.
The default video applications that come bundled with Windows are not always the “best” playback applications. VLC Media Player is probably the most popular application for playing video files in most any format. Switching from a default Windows movie player to VLC Media Player has improved playback for many.
You didn’t mention it but the video codec used can have the largest impact on playability of the video. The newer drones include the ability to encode the video file using the H.265 codec. While being more efficient in compression, the H.265 codec requires more CPU (for software decoding) or more GPU (for hardware decoding). If you are experiencing playback problem, this is one of the first things you should check and perhaps revert to using H.264 instead.
Having to send your video signal to the TV only and turn off the computer display suggests that your GPU is not sufficient for playing a video of that size on two monitors at once.
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Sorry I didn’t provide any details on this. There were two default settings, in particular, which I changed. Under (right click on screen)>>Display Settings>>Graphics>>Movies&TV, I change performance from “Let Windows decide(power savings” to “High Performance (not recommended)”. And under Advanced display, I set the refresh rate to 60 Hz. My second screen is a LD 4K TV which has a 60 Hz. rate. My reason for doing all this is in this thread:
[Mobil Rig for Droning](https://forum.flylitchi.com/t/mobil-rig-for-
droning/13457)
Yes, my target TV has only a 60 Hz. refresh rate, and that why I configured my Mini to record at 4K 30 fps, the fastest rate it will do with 4K.
Yes, I suspected the LG native graphics on board the CPU was struggling a bit, and that’s why I did the experiment. So I think you’re exactly right on this.
I don’t know much about this topic, and I don’t know what the Mini 2 uses. But the TV seems happy with whatever codec it uses.
I down loaded VLC to both of my laptops, and I did not get good results, at least with the out-of-the-box settings. The Movies & TV app still seems to be the best if I’m streaming from a computer. My simplest solution is to simply run the micro SD card directly plugged into the TV in my mobil rig,
Thanks very much for your insights…
That is an awesome mobile rig. That would be very useful when you have to travel some distance and want to make sure your footage is adequate before heading home. Very impressive!
Out of curiosity did you try doing a render of the video and then see how it plays?
Saw this a bit with 4K a few years back, then with 6K would see the stutter a bit more, until render using your preferred video editor and playback was smooth, even in Win 10 among other devices.
I have not tried to re-render the reference video, but I’ll try that in a few days. The video plays “perfectly” from USB inputs to the media servers built into all my 4K TVs, and it plays perfectly with two different media servers on my NAS, over both LAN and WiFi 5G connections to the TVs. By perfect, I mean very minor artifacts left over from the best that a DJI Mini+ can do with yaw jerkiness.
I think the dropped frames I’m seeing are related to limitations of the video processing in my laptops, connected over HDMI to my TVs in various tests. Tweaking the video parameters in both the laptops have helped a lot.
I’m getting pretty good at differentiating between dropped frames vs. yaw jerkiness from the drone. Frame drops happen mostly when the scene is changing a lot, like in a fast yaw turn, or when flying past a tree with many leaves, or flying over rooftops with shingles. Probably due to minimal compression for those types of scenes. Drone yaw jerkiness only shows up in turns–straight-ahead videos are always very smooth.
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