Image Lag

[Ken R]

Does anybody know what the lag time is between the Mavic 2 Pro drone and the controller? I assume it is not realtime, but maybe I am wrong??

 

[zeusfl]

The system was still able to transmit up to 1080p and it had a range of approximately 4.3 miles. It did have a latency of between 160 and 220 milliseconds and the reason for that being so wide was it depended if you were using a smartphone or you were using the plus RC from DJI.

DJI OcuSync 2.0: What is This FPV Transmission System?

In this guide we break down DJI OcuSync, showing you the difference bettwen it and DJI Lightbridge and a few charts of compatibility with DJI Goggles.

djibestdrones.com

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[zeusfl]

Last Updated: April 29, 2020
What Is DJI Ocusync And How Does It Work?
When DJI released the Mavic Pro they decided to change the transmission system that communicates between the remote control and the drone.
The new system is called OcuSync and it has some impressive capabilities worth looking at.
Of course, it also has some differences and downsides to the other transmission technology in the DJI Lightbridge family.

OcuSync Special Capabilities
DJI had some cool ideas when they were designing OcuSync, because they had plans for the DJI Goggles and DJI RE Goggles.
OcuSync was developed with the capability of supporting multiple outputs easily.
The Mavic Pro can be connected to

• 2 controllers
• Multiple DJI Goggles

OcuSync 2.0 Specs (2018)
Occusync 2.0 was released with the Mavic 2.0 model in August 2018. There have been some nice improvements in the technology which I will summarise below:
Video Resolution
Ocusync 2.0 has an upgraded resolution of 1080p for all distances.
Maximum Transmission Distance
10 km (FCC), 6 km (CE), 6 km (SRRC), 6 km (MIC)
Video Download Speed
Video downloads at 40Mb/s just like the Ocusync 1.0.
Live View Video Quality
Resolution/Framerate: 720p@30fps, 1080@p30fps
Transmission Modes
The Mavic 2.0 with Ocusync 2.0 can use either 2.4 GHz and 5.8 GHz which gives it more flexibility when there is a lot of interference in transmission.
It auto-switches between these two frequencies. So, the system is even more robust.
Latency
Latency is also 120-130ms, which is not really an improvement, but we can't have it all, right?
OcuSync 1.0 Specs
Let's go a little deeper and have a look at what the specs are of the Ocusync 1.0 system, which was used on all versions of the Mavic previous to the Mavic 2.0 (Mavic Pro, Mavic Pro Platinum).
Video Resolution
Ocusync can transmit video at 720p or 1080p (at short distances).
It depends on the situation, but in general OcuSync will use 1080p for close range transmission and 720p for long-range transmission. Which makes sense, as it is harder to transmit so much data at longer distances.
Video Download Speed
When things are running well, at a shorter distance and low interference, you can get photo and video downloads at 40Mb/s.
Transmission Modes
THE DJI Mavic Pro using OcuSync starts by scanning for any local interference and then makes a decision between three transmission channels: 20MHz mode, the 10MHz mode, and the lowest priority 1.4MHz mode.
During flight it will then automatically switch between channels (within the chosen mode) if it notices any interference.
So, the system is very robust.
Latency
A big issue with any transmission system is the latency. Which is the amount of delay you experience.
The DJI team have done a great job with the new OcuSync and achieved these values:

• 5ms for remote controller transmission commands
• 10ms for video data
• 130ms for videos

Note: 160ms-170ms from the Mavic’s camera to your device screen under ideal conditions.
Transmission Distance
OcuSync has a great transmission distance and I have seen a lot of videos on Youtube where people have flown these distances.
OcuSync has a range of up to 4.3 miles (7 km).

 

[Not A Speck Of Cereal]

By real-time, do you mean instantaneous? Because no camera that I know of is that quick (they all have some lag, even a pro DSLR).

That said, this camera probably has more lag than most pro cameras. Add to that the wireless signal distance with potential for interference, it's safe to say that that the shutter actuation is not so quick that you could use it for critical stuff (like pro sports).

As for taking the next shot, I always wait for the DJI GO Camera button to stop with it's animated circle indicating that it's still working on the shot you just took. This is especially true with AEB and burst modes (you'd think they took them all rapidly and then the wait is just write times, but I've screwed some up by moving the aircraft before the "write" animation of the shutter button is finished. So I wait.

Chris

 

[Ken R]

Those numbers are better than I expected. Thanks for the info!!

Ken