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Excessive Camera Latency

(Doug) #1

I was operating Blue ROV 2 in my pool and the latency for the camera increased to over 1 second. So I tried just rebooting system to see if made any difference. It did not. I then tried my Microsoft computer vs my Mac and while on deck sitting still appeared to go back to normal 1/4 second roughly. I put in pull and a minute later latency was back over a second.

I was discussing with my friend about video compression and how sitting still vs. moving impacts the memory and processor speed. I have a pebble-etc finish pool with small multi colored pebble finish. Between that and streaks of sunlight scattering about like crazy with wave ripples, could this be overloading processor and increasing latency?

(undersearobotics.com) #2

@dtrail - What version ArduSub and QGround Control are you using? I got a report from another user that he’s experiencing much greater latency (from 200 msec using an older version to 1-2 sec per frame using the latest versions) after updating to the latest versions of ArduSub and QGC.
He is also using Windows 10.

@rjehangir - Any suggestions/feedback? Could this be related to the new video record to file feature?

(Doug) #3

ArduSub 3.5.0 Both Computers

Ground Head c728d58fa 2017-06-25 Windows 10 (No record Function)

Ground Head 75490d3 2017-06-15 MacBook Pro (has Record Function but not set up to use.)

Did another test on Windows computer and on deck with only movement of my foot to test response seemed normal approx 200 ms. Than put in front of pool with constant ripples of waves caused by spill over of hot tub for few minutes in testing response to tilt latency increased to a second or so.

I then rebooted macbook and started QGround with nothing else. Was running out of daylight but couldn’t get it to have longer latency looking at pool after five minutes all about 200 ms. Shutting down for the night.


(Jacob) #4

There are various things that can cause this. Doug there aren’t any issues in the version you posted that I am aware of that would cause this. If we can zero in on the problem, then we can fix it. It would be best if we could come up with a set of steps to reproduce it consistently, but that might not be possible. It looks like you may be on to something with the resource usage on your mac. Try using the system monitor to see the cpu and ram usage to see if that is the cause.


(Doug) #5

I might appear first thing I need to do is reboot computer and open QGround only to see if that helps. I would like to know if the camera is using a codec prior to transmitting. I will use activity monitor for every dive going forward.

Note my MacBook has 16 GB Ram which I would think would be more than sufficient. Is there any recommendations on processor speeds and RAM?

(Jacob) #6

@dtrail The camera and video stream use H.264 compression.

Adequate hardware depends on the CPU line, OS, and other processes running, but in general I think that a quadcore i5 or i7 >=2GHz with 8GB RAM should be comfortable running QGC. I think your macbook should be fine to run QGC. Let me know if you keep running into this issue with a lot of stuff going on in the frame, I haven’t personally done a lot of testing in this scenario.


(Jacob) #7

@paul-unterweiser There is a known issue causing lag on some windows machines. You can get a different QGC to correct that here (Doug is using this one currently on his windows machine). Bo has also posted some tips in that thread that can be the cause of lag.

(Ion Hernandez) #8

We use one laptop with i3 2GHz Ram and W10 and goes good. The same with W7 no video. The version ofQGC has some months, I don’t know the version

(undersearobotics.com) #9

@jwalser - Thanks! I’ll give that a try and pass it along.

(David Ardis) #10

I am using a Panasonic Toughpad running windows 8 and have discovered that there is a lag in video if the toughpad is not plugged into exteral power. Hope this is helpful to someone

David Ardis

(Marcus) #11

It might be worth checking, I found the caps on the bare ends of one of the conductors was loose, and this was causing lagging video. I trimmed them off, tinned the ends and it works great.