Video Issues with Cendence and CrystalSky Master and Slave

[RoryG]

I'm having a major video issue with my Inspire 2 with Cendence master and slave and two CrystalSky 7" screens. Basically on one of the devices the video is broken up with a huge lag, although all controls are responsive. This doesn't happen every time, but more times than not. On the slave controller I can output the video via HDMI and it is perfect, even though the CrystalSky video is no use. Sometimes it's the master device that exhibits the issue, sometimes the slave - any ideas? The video looks like the old problem with DJI Go running in the background but that is not used on either CrystalSky. Both CrystalSkys are running the latest firmware. If I swap the screens over when it’s all up and running then the problem transfers to the other controller, so I would say definitely a CrystalSky issue.

 

[Donnie Frank]

When did the problem start?

Also, I'm unfamiliar with the Cendence set up. Just spitballin'... I would plug in an Android or iPad to tease out the source of the problem.

D

 

[RoryG]

When did the problem start?

Also, I'm unfamiliar with the Cendence set up. Just spitballin'... I would plug in an Android or iPad to tease out the source of the problem.

D

Thanks Donnie. I had changed the standard slave controller to a Cendence with CrystalSky, and used a CrystalSky on the master when the problem first appeared (before that I was using a Cendence with an iPad as the master). Using an iPad seems to cure it but I only have one screen mounting bracket to put an iPad on the Cendence. This morning I set it all up and the issue was still there, however I rebooted everything about 10 times and the problem didn't show up again, but we have a shoot tomorrow and guaranteed it will glitch on set! The other major change is using the X7 instead of the X5 - I haven't tried the X5 on the setup yet as our client specifically requested the X7. At first I thought it was RF interference from set cameras but it did it first thing today with nothing pushing out RF in the vicinity. I have tried playing around with the transmission settings but makes no difference.

If the worst comes to the worst I can put the cam op back on a standard controller with an iPad and I can use an iPad on the Cendence, however having replaceable batteries for the controllers and screens is the reason I bought the other Cendence and CrystalSky in the first place; we can change and charge and still fly, rather than having to charge the iPads and standard remote which brings us to a stop. The annoying thing is we tested this all out before the shoot and it seemed to work fine!

 

[Donnie Frank]

Thanks Donnie. I had changed the standard slave controller to a Cendence with CrystalSky, and used a CrystalSky on the master when the problem first appeared (before that I was using a Cendence with an iPad as the master). Using an iPad seems to cure it but I only have one screen mounting bracket to put an iPad on the Cendence. This morning I set it all up and the issue was still there, however I rebooted everything about 10 times and the problem didn't show up again, but we have a shoot tomorrow and guaranteed it will glitch on set!

Yep...Murphy's Law goes into overtime on set.

The other major change is using the X7 instead of the X5 - I haven't tried the X5 on the setup yet as our client specifically requested the X7.

Unfortunately, it looks like you may have broken one of my personal rules; Never change more than one thing. (Maybe you didn't, so forgive me if I'm wrong).

It sounds like you have a handle on the troubleshooting regimen by simply changing back to old devices. Obviously, you don't have time to flush all this out today. I don't think I need to tell you to just bring EVERYTHING to set so you can switch out your tablets if need be.

FWIW, I found goggles to be much better for me as a camera operator. Do you have goggles? I found the FatShark Dominator 2's did an excellent job. They get a direct feed off the HDMI port. So when all else failed, they worked. I wouldn't shoot without them. This allowed me to hand the iPad to the DP, which he could then use his coat as a shade or whatever for shooting in direct sunlight. It was actually a very good work flow. This was back when the Inspire 1 was the new kid on the block, so I concede things may have changed since then.

At first I thought it was RF interference from set cameras but it did it first thing today with nothing pushing out RF in the vicinity.

I find there is a LOT more RF issues these days than a mere 7 or 8 years ago when I was doing film work. Nowadays I use the RF histogram every shoot to find a clear channel. This has been absolutely paramount to insure successful flights.

As you can see in this screenshot, even with the 32-channel hack I often have a hard time finding a clear channel. So conducting on-site RF forensics before flying is an absolute must. I don't know what frequencies the Inspire 2 uses, so all of this may be moot.

If the worst comes to the worst I can put the cam op back on a standard controller with an iPad...

Does he have goggles? I swore by mine. My composition was very accurate with goggles. I had the DP keep an eye on the histogram for exposure. Again, it was a good work flow. The DP seemed comfortable with it.

...and I can use an iPad on the Cendence, however having replaceable batteries for the controllers and screens is the reason I bought the other Cendence and CrystalSky in the first place; we can change and charge and still fly, rather than having to charge the iPads and standard remote which brings us to a stop.

Yep....that is one heckuva carrot. We managed to do 10-hour days on single controller charges (master/slave). We had spare iPads to switch out and I had a spare battery for my goggles. I think controllers now use a lot more power than the older ones.

The annoying thing is we tested this all out before the shoot and it seemed to work fine!

Yeah...Murphy's Law... I think if you operate and kit up as if everything is going to fail, you will be okay....<;^)

Honestly, I don't miss those 10-hour days on set. I LIKED the film industry. I didn't love it. Now I do mostly mapping and some construction progress videos. A LOT less pressure....<;^)

Best of luck.

D

 

[RoryG]

Yep...Murphy's Law goes into overtime on set.





Unfortunately, it looks like you may have broken one of my personal rules; Never change more than one thing. (Maybe you didn't, so forgive me if I'm wrong).

It sounds like you have a handle on the troubleshooting regimen by simply changing back to old devices. Obviously, you don't have time to flush all this out today. I don't think I need to tell you to just bring EVERYTHING to set so you can switch out your tablets if need be.

FWIW, I found goggles to be much better for me as a camera operator. Do you have goggles? I found the FatShark Dominator 2's did an excellent job. They get a direct feed off the HDMI port. So when all else failed, they worked. I wouldn't shoot without them. This allowed me to hand the iPad to the DP, which he could then use his coat as a shade or whatever for shooting in direct sunlight. It was actually a very good work flow. This was back when the Inspire 1 was the new kid on the block, so I concede things may have changed since then.







I find there is a LOT more RF issues these days than a mere 7 or 8 years ago when I was doing film work. Nowadays I use the RF histogram every shoot to find a clear channel. This has been absolutely paramount to insure successful flights.

As you can see in this screenshot, even with the 32-channel hack I often have a hard time finding a clear channel. So conducting on-site RF forensics before flying is an absolute must. I don't know what frequencies the Inspire 2 uses, so all of this may be moot.
View attachment 33605






Does he have goggles? I swore by mine. My composition was very accurate with goggles. I had the DP keep an eye on the histogram for exposure. Again, it was a good work flow. The DP seemed comfortable with it.





Yep....that is one heckuva carrot. We managed to do 10-hour days on single controller charges (master/slave). We had spare iPads to switch out and I had a spare battery for my goggles. I think controllers now use a lot more power than the older ones.





Yeah...Murphy's Law... I think if you operate and kit up as if everything is going to fail, you will be okay....<;^)

Honestly, I don't miss those 10-hour days on set. I LIKED the film industry. I didn't love it. Now I do mostly mapping and some construction progress videos. A LOT less pressure....<;^)

Best of luck.

D

Hi Donnie, thanks for the detailed reply. The cam op uses a high brightness Atomos monitor / recorder that the director / DP can also view, and we record on it for immediate playback after each take. We don’t have any googles but it’s an interesting idea!

We have all the backup kit so can quickly put it back the way it was (as we did on Friday), but I really want to get this setup working. Like you I don’t like making multiple changes at the same time, however I think this is definitely a CrystalSky issue rather than anything to do with the X7. What makes it so frustrating is i comes and goes (which does point at RF interference), however yesterday all the channels were pretty clear.

I hear you with the 10 hour days on set! Many hours spent doing nothing then the drone team is called and it’s all go for the shots. We often work with the 2nd unit or even as a drone splinter unit (usually for car stuff and GVs) which is far more enjoyable than the main unit!

We’re called for 10:30 this morning so fingers crossed it will all work like it did yesterday.

Cheers,

Rory

 

[Donnie Frank]

Hi Donnie, thanks for the detailed reply. The cam op uses a high brightness Atomos monitor / recorder that the director / DP can also view, and we record on it for immediate playback after each take.

We kind of had that ability (you can playback via the iPad via the Inspire 1), but the drone has to be powered up. So we never really used playback very often.

We don’t have any googles but it’s an interesting idea!

I'm telling ya, it was a great way to shoot. No sun issues. It's like you're in your own world. "Immersive" as they say. If I had to move around, I would get a PA to hold my shoulder to guide me around during that shot. But that kind of scenario happened MAYBE 1% of the time. I can count on one hand how many times I had to move around with the PIC. The PIC did all the moving.

We have all the backup kit...

I figured you would. Nobody shows up to set unprepared. You get one pass, MAYBE two if you're lucky...LOL....

...so can quickly put it back the way it was (as we did on Friday), but I really want to get this setup working.

It sounds like a good rig. Please let me know how your shoot went.

Like you I don’t like making multiple changes at the same time, however I think this is definitely a CrystalSky issue rather than anything to do with the X7. What makes it so frustrating is i comes and goes (which does point at RF interference), however yesterday all the channels were pretty clear.

I did some research and I was actually kind of shocked to find out the Inspire 2 uses the same Microwave frequencies as DJI's non-Enterprise/Professional drones. I honestly thought DJI would've moved their Pro/Enterprise drones out of that RF soup. I guess not.

Here's something that might help. There's a Windows app I started using called WiFi Analyzer. This not only analyzes microwaves but also analyzes the 5Ghz environment. It can only be installed through the MS store...maddening. I HATE creating accounts...but I digress....



Unfortunately, it is a Windows-only app, but I use it a LOT. I know you probably don't have time to babysit a Windows tablet on set, but assuming you have a third to manage batteries and data, maybe he can kind of keep an eye on the WiFi situation. This may help you troubleshoot your issues.

What I haven't quite reconciled is how DJI parses out 2.4 GHz into 8 channels. A typical router has 11 channels (as you can see in the screenshot above). Regarding DJI, here's the best answer I got from ChatGPT:

"The 2.4 GHz frequency band is divided into 14 channels, but only 8 channels are typically used by DJI drones. These 8 channels are spaced 5 MHz apart, and they are numbered from 1 to 8. Each channel has a specific center frequency that is used for communication between the drone and remote controller."

I had to jailbreak ChatGPT to get a real (albeit, incomplete) answer:




Either the 32 channel hack nets 12 more channels on both sides of the microwave spectrum, OR it divides the same spectrum into small slices (for a total of 24 more channels). My research is incomplete at this point. I can only hope it's the former - that the 20 MHz separation continues up and down both sides of the spectrum.

At any rate, this information combined with the WiFi Analyzer should help paint a clearer picture as you try to tease out your possible WiFi issues.

I hear you with the 10 hour days on set!

We had to actually rewrite our contract to discourage TWELVE hour days. You reach a point where no amount of money is worth 12 hours. As I recall, we billed out $4500 for an 8-hour day, which included kit rental. Me and my business partner paid a "battery b****" 500 bucks for the day. We then billed $500/hour for anything over 8 starting @ 8H 1M and then $1000/hour for anything over 10. We just tossed that in there because neither of us wanted to work more than 10. I think we got into "Golden Hour" ONE time (well...our version of Golden Hour....LOL....). It was good money. I know nowadays guys are billing way higher than that. But our investment at the time was a pair of Inspire 1's with X3 and X5 cameras. When the industry started migrating towards RAW, we knew we were at a crossroads to either further commit with a sizeable kit investment or move on. By that time we'd been doing film a couple years and we were both kind of ready to move on. Mapping actually pays better without having to deal with those flakes and their flakey schedules...LOL.... I'm sure I don't have to tell you about it.

Many hours spent doing nothing then the drone team is called and it’s all go for the shots.

We worked with this one director/DP (we'll call him Bill) shooting a couple different series. This guy would have "Drone day." We pretty much shot the entire day, back-to-back shots, ALL DAY. Brutal. This one day he says, "I'm going to have you working with the VFX guy today." Keep in mind that Bill was a director, NOT a real DP. So I said to him, "You know we're shooting compressed footage" (h.264 back then). He shrugs like he has no idea what I'm talking about. So we get with the VFX guy and I mention that we were shooting h.264. And he immediately gets pissed off. I explain to him that I tried to explain to production that this would happen. I framed as production was not willing to pay for RAW (which we actually didn't have that capability, but I didn't tell him that). He kind of nodded and "got it." We shot with that guy for HOURS and not a single shred made it into the pilot. It was the pilot for "Tremors," which never even made it to air. Our shots were of the Graboid's POV. That footage never saw the light of day.

We often work with the 2nd unit or even as a drone splinter unit (usually for car stuff and GVs) which is far more enjoyable than the main unit!

Agreed. 2nd Unit is more relaxed but the catering isn't nearly as good....<;^)

Ironically, I worked 1st unit exclusively for a couple years as a Set Lighting Technician (IATSE Local 480 out of Santa Fe) before quitting the Union and moving on to drone work. From there, as you eluded to, we went to 2nd Unit and/or a "Drone Unit" or whatever that was called...LOL....

We’re called for 10:30 this morning so fingers crossed it will all work like it did yesterday.

Good luck. It will be interesting to see if you're able to tease this out. Hopefully, maybe some of the tools and information I've given here will help you out.

I have an undergrad degree in Computer Science, so I have some Cisco networking classes under my belt. It's amazing how much these drones (and even my sound company) rely on networking, and how little most pilots (and audio engineers) know about it. One of my best buddies used to be Alice Cooper's FOH engineer. I STILL get calls from him out on shows when he has wireless issues. Good times.

Good luck!

D