So according to Pilot Institute the master googles rebroadcast the signal to the slaves? I doubt that but it would be very easy to test, just have the master and slave and start separating them at the same time flying the drone towards the slave set. If in fact the master is rebroadcasting you would start to loose the picture on slave set really fast considering all the obstacles at ground level. Anyone near Naples, FL wants to test it I am game.
DJI FPV Video Quality Problems With Second Goggles
- Thread starter Chaosrider@brilliantfrogs
- Start date
Dunno about that. The audience goggles getting their signal from the primary goggles is consistent with the somewhat fuzzy description that I got from DJI, and also consistent the reported occasional crummy video feed in the audience goggles.
I think it's a lousy, excessive-data-control driven architecture, but it's the best fit that I've seen for the data that I've collected from various sources.
IIRC, DJI said the the slave goggles (and apparently the master can have an unlimited number of slaves) should also be very close to the master goggles for best signal.
Which, since I sit while I fly, is unlikely to prove to be a problem.
I won't know until I get the second pair, and that probably won't be soon.
Thx,
MM-FPV!
I can confirm that the second pair must be close for the strongest signal. I notice a significant degrading of video on the audience set when not very close.
The more I look at this issue the more I'm convinced I don't know what the communications architecture is.
Supporting the supposition that the secondary goggles don't have a link to the primary goggles I've noticed
1) It doesn't seem to matter how close the primary and secondary are to each other,
2) When the secondary is turned on and connected an airspace warning appears that is identical to that seen in the primary. This occurs even if the warning was dismissed in the primary before the secondary is connected. If the secondary got the warning info from the primary then the primary would have to remember the warning to transmit it to the secondary.
3) In my experience there are several particular drone locations that will reliably cause secondary pixelation problems.
Supporting the supposition that the secondary is linked to the primary
1) The secondary won't connect and show the drone info unless the primary is connected to the drone.
Supporting the supposition that the secondary goggles don't have a link to the primary goggles I've noticed
1) It doesn't seem to matter how close the primary and secondary are to each other,
2) When the secondary is turned on and connected an airspace warning appears that is identical to that seen in the primary. This occurs even if the warning was dismissed in the primary before the secondary is connected. If the secondary got the warning info from the primary then the primary would have to remember the warning to transmit it to the secondary.
3) In my experience there are several particular drone locations that will reliably cause secondary pixelation problems.
Supporting the supposition that the secondary is linked to the primary
1) The secondary won't connect and show the drone info unless the primary is connected to the drone.
The clear majority of the reports that I've seen say that the two goggles must be close together to maintain signal quality.
DJI explicitly told me that was the case.
I consider this matter settled, unless someone can conclusively demonstrate that the audience goggles don't get their signal from the primary goggles.
Also, DJI is extremely (excessively?) linkage and control conscious. Having the audience goggles get their signal from the primary maintains tighter control.
And having just completed my firth DJI FPV flight, pushing the signal envelopes a little bit harder, my primary (so far only) goggles got pixelated on several occasions. It got my FULL attention the first time, but it recovers quickly. So, if the audience goggles pixelate from time to time, it's not going to ruin the FPV experience, as I had originally feared.
Thx
I have also been told explicitly by DJI that the link is between the primary and secondary. But, I have also been told explicitly by DJI that the link is between the secondary and the drone.
I did an experiment to see if the distance between the primary and secondary made any difference. Take a look at
Audience Mode Quality
You may have already looked at the comparison between primary and secondary back in post #11
Considering everything that so far has been said here, if the master does broadcast wouldn't that:
- increase video latency? would that be visible in the recordings from master and slave googles?
- shorten runtime of master googles?
Also, why would you get any pixelization on slave granted master is close to slave?
I wonder if anyone could try what I suggested in post #41? Would that give a definitive answer?
- increase video latency? would that be visible in the recordings from master and slave googles?
- shorten runtime of master googles?
Also, why would you get any pixelization on slave granted master is close to slave?
I wonder if anyone could try what I suggested in post #41? Would that give a definitive answer?
There could be some latency but it would hard to measure it. When I made the video comparing the secondary and primary it was apparent that the video recordings don't start at exactly the same time. They were already off by 2 or 3 seconds and required some adjusting in the editing software.
The runtime of the primary goggles may be shortened. But, here again, it may be hard to measure.
The test you suggested presents some logistical problems for me. But, I'm forming up with my flying buddy this morning and we might be able to figure out something.
I've been thinking about how can both scenarios can be true. One way is that the secondary video feed comes from the drone to the primary goggles via a sub channel that is not error corrected. Then from the primary to the secondary. But, an obvious question is why have the sub channel in the first place.
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It can't dissociate between "primary goggles send whole video stream to audience goggles" and "audience goggles get the video from the aircraft, but along must come a side channel with decryption keys allowing to decode it from the master goggles"
Finally managed to fly some yesterday. Not much progress was made on determining what influences the audience pixelation problem. It was worse than usual. I tried two experiments where the primary goggles were placed on a plastic chair and I used the audience goggles to fly.
The first was to separate the primary and audience by about 300 feet then try flying the drone back and forth between the two locations. The only thing I noticed was that the pixelation got momentarily worse coincident with the abrupt attitude changes. Didn't seem to depend on how close the drone was to the audience goggles.
The second experiment was to fly the drone out about 1500 feet and then lower it close to the ground. This particular location has always been a reliable way to cause the audience pixelation. Yesterday the pixelation was uniformly worse than usual so I can't really say it got worse during this test. But, here also, it seems the pixelation would get worse when an abrupt attitude change would occur.
I'm going to try, once again, the theory that pixelation is correlated with increased fan speed.
Audience Mode Quality
The first was to separate the primary and audience by about 300 feet then try flying the drone back and forth between the two locations. The only thing I noticed was that the pixelation got momentarily worse coincident with the abrupt attitude changes. Didn't seem to depend on how close the drone was to the audience goggles.
The second experiment was to fly the drone out about 1500 feet and then lower it close to the ground. This particular location has always been a reliable way to cause the audience pixelation. Yesterday the pixelation was uniformly worse than usual so I can't really say it got worse during this test. But, here also, it seems the pixelation would get worse when an abrupt attitude change would occur.
I'm going to try, once again, the theory that pixelation is correlated with increased fan speed.
Audience Mode Quality
MrScharfenberger
New Member
I bought the 2nd set of goggles and have used them a good number of times now. Video quality does indeed kind of suck. I have searched for solutions and have found none so far. Looks like it's just the way it is. I do like the idea of broadcasting my phone to my smart TV so others can see. I'm going to set that up. Thanks for the idea.
With all that said I have noticed that going slow with less turns, climbs & dives really help video quality. If you just let it sit and hover video quality is pretty much perfect. It's when you start ripping around that video quality starts to really suck bad.
With all that said I have noticed that going slow with less turns, climbs & dives really help video quality. If you just let it sit and hover video quality is pretty much perfect. It's when you start ripping around that video quality starts to really suck bad.
I've noticed something like that just with the regular single set of goggles. If I'm just sort of wandering around checking out the rocks, I get much better video range than if I'm zipping along at Warp 6.
If it's 1500 ft away and just hovering, the video quality is nice and stable. If I'm zipping and twisting around at that distance, the video signal will frequently pixelate, and sometimes disconnect entirely, triggering an RTH.
I sure wish I could find out what it is about the system configuration that causes that to be far worse with the second set of goggles. It doesn't have to be that way, but sadly, it's pretty clear that it *is* that way.
MrScharfenberger
New Member
It could just be where you are and you have a lot of interference. To be honest my main set of goggles are pretty much flawless unless I get a lot of objects in between my goggles & drone. Then it will pixilate. But...if I have clear line of sight I can fly that sucker thousands & thousands of feet away and be as quick and twisty as I want and my controller goggles picture is still pretty much perfect. In fact I'm often amazed at just how good the main set of goggles is. F'n crazy good if you ask me. At least that's been my experience. I was up in Minnesota in the middle of nowhere 2 weeks ago and flew the thing more than 10,000 feet away. Zero signal issues.
Disable Broadcast mode if you're not going to have someone with the 2nd set of goggles, having it on is enough to mess the transmission.
I agree on the primary goggles, they are awesome!
There are lots of rocks and ridges in the area, and when I'm zippy around at Warp 6, I'm usually pretty close to them. I'll pay a little more attention to when the pixilation starts, and run some tests to get a better handle on how much movement impacts the video quality.
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