So I took my P4 to a remote location (a walk about 10 km each way), filmed what I thought was amazing footage, checked the cached footage on my iPhone (and yes it was all there), but when I got home, I discovered that NO footage was recorded to the SD card!!! Something strange did happen when I was recording. I received the "SD Card is full" message, and I thought it was odd because I still had 20 GB of free space left on the 32 GB card, and I had only flown for about 10 minutes. The card is a Sandisk Class 10, UHS-1 (32 GB).

I'm just wondering whether the SD card is corrupt? It managed to successfully record about 10 GB of footage the day before with no problems at all. This is a VERY frustrating problem, and frankly I am absolutely livid, given all the effort I invested to get the shots I wanted.

Another thing I guess is worth mentioning, is that it took many attempts to calibrate the compasses, as the App complained of high levels of interference. I had all my wifi and phone signal disabled, and the RC was nowhere near the P4. I just wonder whether something in the area not only caused compass problems, but also caused SD card problems?

Did you close off the recording before powering down the Phantom?
If that's the problem, put the card back in and power cycle the Phantom

labroides@yahoo Posted at 2016-4-16 15:41
Did you close off the recording before powering down the Phantom?
If that's the problem, put the car ...

Yes, I always power down the Phantom first. I did lose RC signal at one point, which triggered RTH, but I wouldn't have thought that would cause video recording problems. I'm also pretty sure I accessed the actual files on the P4 (when you press that Play button in the App), rather than the video that was just cached to the iPhone, and the videos were all there. It's as if they have just vanished without a trace before I arrived home!

NickTony Posted at 2016-4-16 01:46
Yes, I always power down the Phantom first. I did lose RC signal at one point, which triggered RTH ...

did you try putting the card back in the p3 and starting the drone up?   may beable to repair the video if it corrupted it by some chance durring shut down.

if not gonna have to google up SD card recovery programs

quickpoint Posted at 2016-4-16 15:51
did you try putting the card back in the p3 and starting the drone up?   may beable to repair the  ...

I just scanned with one data recovery program. It found absolutely nothing. I will some more programs now.

NickTony Posted at 2016-4-16 15:46
Yes, I always power down the Phantom first. I did lose RC signal at one point, which triggered RTH ...

Just try what Labroides said, put the card back in the Phantom and power it up. After 30 seconds or so, you can shut it down and remove the card to check if there is any video files on there.

There are other issues that can cause the 'card full' message. One think to ask is what resolution you were shooting at? I only use Sandisk Extreme or Extreme Pro series cards, because they are fast enough for 4K work. To shoot 4K, the camera needs a card that is able to write at 60 megabits per second. The Class 10 rating is misused by manufacturers and it is not the best way to specify the speed required.

There is also another subtle issue that can trip you up, and that is copying files off the SD card and then deleting them, or using the cut command. If you do this repeatedly, the card will start to slow down in its write speed because of fragmentation on the card. The best technique is to copy all the files off your card at the end of a session, then immediately re-format the card in the camera on the Phantom, using the format command in the Go App. This clears the file allocation table and makes it easier and quicker for the camera to write information.

With regard to the compass problem, it is not radio interference the App is complaining about, it is magnetic or metal objects near the aircraft. These affect the compass badly. Do not, for example, perform the compass routine over a concrete driveway, do it on some grass, well away from any metal object, particularly cars. Also, make sure you take any metal objects out of your pockets. Once you have a good compass calibration, leave it, it is a fallacy about having to calibrate the compass all the time. I have only ever done mine once in 6 months.

NickTony Posted at 2016-4-16 15:55
I just scanned with one data recovery program. It found absolutely nothing. I will some more progr ...

And other programs will not find anything either. When you get the message 'SD card full' it really means it, as in nothing will be recorded.

Geebax Posted at 2016-4-16 15:57
Just try what Labroides said, put the card back in the Phantom and power it up. After 30 seconds or ...

Thanks for the tips.

I reinserted the card into the Phantom, powered it on, waited 30 seconds, powered it down, inserted the card into the computer, and there is still nothing on there except the footage I recorded yesterday.

I was shooting at 4K resolution. According to the P4 manual, a Class 10, UHS-1 card is required. This is exactly what I was using. I see nothing in the manual about a particular MB/s, as I assume all cards that meet the above criteria would be fast enough. If this is not the case, then why does DJI not specify a certain write speed?

I have yet to delete any files on the card, so cutting rather than copying is irrelevant (and I never do that anyway). I always format my cards once they are full and their contents are transferred to my hard drive. However as this card was nowhere near full, I saw no need to do that. The whole point of me getting a 32 GB card was to cut back on the number of times I would need to copy the card, then format it for another flight.

I agree with what you said about compass calibration. I never calibrate it unless I am told to do so. It is so rare for me to be asked to calibrate, so I was a little surprised when it did. When I did try, it took many attempts. When I think about it, the only thing that could have caused issues was my wallet in my  pocket which I didn't remove (which did not contain any coins, only credit cards, and the only thing metal was a single zip inside).

Geebax Posted at 2016-4-16 16:03
And other programs will not find anything either. When you get the message 'SD card full' it reall ...

That message only appeared after about 10 minutes of flying. I don't think you read my message properly. I never said that the "SD Card full" message appeared at the start!

NickTony Posted at 2016-4-16 16:22
Thanks for the tips.

I reinserted the card into the Phantom, powered it on, waited 30 seconds, p ...

I missed the bit about the compass issue.
When you get a compass error it's usually your compass telling you it has detected an error ... not that there is something wrong with the compass.
The most common cause is putting the Phantom close to steel and reinforced concrete is the most frequent offender.
Simply moving to another location is the solution and recalibrating close to the offending steel is a no-no.

With the SD card issue, it's a good idea to copy your images and videos rather than risking them every time you fly.
I use a bunch of 16 GB cards and swap them every flight so that whatever I just shot is safe.

Geebax Posted at 2016-4-16 13:57
Just try what Labroides said, put the card back in the Phantom and power it up. After 30 seconds or ...

Generally you are right about the write speeds of the card and is something I've been preaching forever to no avail but now here. Even at full 4K or UHD @ full frame rate even though it says it needs like a 50mbps constant or higher rate, that will work fine but won't hold that against you since you know it.

You do need to be away from metal, not radio interference etc when calibrating the "compass". An electronic "compass" is really called an wlectromagnemeter and we have two of them and two IMUs that work together. What the electeomagnemeter does is it measures the magnets in the Earth so the bird can act as a compass. The Internal Measuring Unit or IMU uses these calculations and the gyrometets and such in the phone and the bird for purposes of knowing what it has to do to go where you want it.

As for the card, you cannot fragment an SSD or a flash card which is essentially the same as an SSD. Now what you are wrong about is that the simple act of erasing and re-erasing will fragment it. That's not true. What happens with solid state memory is that it cannot erase like an HDD or regular drive because it writes and if it needs the space in front of it.

If it already has space, it goes directly to that empty space. If you had a card that you were writing over, it would erase the next block and then write over the empty space. In order to prevent this from happening, you can set your SSD or sometimes your flash cards to "trim" mode but you have to set it yourself.

Also, setting the format of the card to exfat instead of the more compatible Fat32 which was invented with the zero (exfat was made in 2006) to help correct the problems with FAT32 while being almost as compatible. No more 4 gig limits and an auto-trim mode. If you can format exfat over Fat32, do it.

On phone and can't see other issues but had some weird issues like that today myself. I was getting terrible reception, bad wind, and the GPS wasn't working great.

That reminds me, don't listen to the replier about calibrating. Whenever you move to a location that is not the last location you were at, CALIBRATE THE COMPASS! Don't know where people are pulling the BS that it doesn't matter because they've been doing it for a year.

Great but on year 1.2, don't tell us when you start spinning and fly away when you're not looking for a sec.

Nobody expects a flyaway.

IMU you should change with the weather simply so you don't have to wait.

Best of luck!

adamcohn95 Posted at 2016-4-16 16:54
Generally you are right about the write speeds of the card and is something I've been preaching fo ...

"Don't know where people are pulling the BS"

Maybe because it isn't BS but is something that's been proved effective by hundreds of experienced flyers over the last couple of years.

adamcohn95 Posted at 2016-4-16 02:54
Generally you are right about the write speeds of the card and is something I've been preaching fo ...

Thanks for your input.
Well it appears as if my lost files have been found and are recoverable (which a preview version of a card recovery program has revealed). Now all I have to do is find another program that isn't expecting me to pay $50 for the full version.

NickTony Posted at 2016-4-16 17:08
Thanks for your input.
Well it appears as if my lost files have been found and are recoverable (whi ...

Are you sure they are the files you lost? Those recovery programs often throw up a bunch of files that were erased some time ago. You then pay the money and find they are not the ones you wanted. Recovery programs are not difficult applications, you should not have to pay money for them.

adamcohn95 Posted at 2016-4-16 16:54
Generally you are right about the write speeds of the card and is something I've been preaching fo ...

'That reminds me, don't listen to the replier about calibrating. Whenever you move to a location that is not the last location you were at, CALIBRATE THE COMPASS! Don't know where people are pulling the BS that it doesn't matter because they've been doing it for a year.'

Don't listen to this guy, the issue of compass calibration is something he does not understand. The only reason to re-calibrate is because of differences in the magnetic field of the earth from place to place, and it does not actually change that much, only a degree or two here and there, and that will not affect the operation of your aircraft to any significant degree.

Experienced flyers know it is not necessary to calibrate in each new place, but if you do, you increase the chances of getting a bad compass calibration that could cause erratic operation of your aircraft.

adamcohn95 Posted at 2016-4-16 16:54
Generally you are right about the write speeds of the card and is something I've been preaching fo ...

'Also, setting the format of the card to exfat instead of the more compatible Fat32 which was invented with the zero (exfat was made in 2006) to help correct the problems with FAT32 while being almost as compatible. No more 4 gig limits and an auto-trim mode. If you can format exfat over Fat32, do it.'

Another falsehood. You can format the SD card to exFAT but the camera will still split the video files at the 4GB boundary, and it does not utilise the auto-trim function. Perhaps you might like to check your facts before you post this misleading information.

adamcohn95 Posted at 2016-4-16 16:54
Generally you are right about the write speeds of the card and is something I've been preaching fo ...

'As for the card, you cannot fragment an SSD or a flash card which is essentially the same as an SSD. Now what you are wrong about is that the simple act of erasing and re-erasing will fragment it. That's not true. What happens with solid state memory is that it cannot erase like an HDD or regular drive because it writes and if it needs the space in front of it.'

Oh dear. There you go again. Yes, you can get fragmented files in an SD card. Granted, it does not suffer the penalty of having to consume time moving the heads from one place to another, as happens on a spinning disk, but there is processing overhead in the process that has to read the file allocation table and determine where the next block of data can be written. In a system like the gimbal of the Phantom, all of that is taken care of by a proprietary chip, and it is not particularly sophisticated. Added to that, the chip has very little buffering for writing to the card, and this is where the problem arises. If it can read the card and determine that successive blocks are contiguous, it can write faster than if it has to look up each block beforehand. An SD card has the ability to page wtite, where it can write large blocks faster and more efficiently.

If the card is on the border of not being fast enough, the added overhead of FAT lookup can cause it to overrun the buffer and fail to write. More sophisticated devices then elect to drop frames in order to deal with the problem, but the chip used in the Phantom does not, it simply gives up writing and squeals an error.

BTW, this issue of slow writing caused by fragmentation has been properly documented and is well know to people in the electronic cinema camera community, and has been proven by proper testing.

My hope for recovery was a false alarm. I am just going to have to accept that the files did not actually get recorded properly (one recovery program "recovered" some SWF files, each several GBs in size, and changing the extension to MOV did not help any programs to play them back). I do believe it's because my SD card was not able to write fast enough. Checking the packaging, it says it is only "up to 48 MB/s", and it mentions that it is good enough for 1080p video, but there is no mention of 4K. Whereas the SD card that comes with the P4, the 633x Lexar, can write faster than 90 MB/s.

It is still interesting though that the 32 GB card was able to write some 4K footage when it was mostly empty, but once it filled up to about a third of its capacity, it was unable to write any more 4K footage properly.

So I'm just going to have to buy some better SD cards, hike back to the location some time in the near future, and start all over again (and the weather today was perfect!)

NickTony Posted at 2016-4-16 18:50
My hope for recovery was a false alarm. I am just going to have to accept that the files did not act ...

Yeah, sorry about your lost footage. I hope you can shoot it again to your satisfaction. Not to harp on the message too much, that is a classic case of the card being almost fast enough, but not quite. Once is gets a bit full, the extra overhead just tipped it over the edge.

I would suggest you get yourself a couple of 16GB Sandisk Extreme or Extreme Pro cards, they are rated fast enough for the job. And it also means you don't have all your eggs in the one basket.

Geebax Posted at 2016-4-16 20:05
Yeah, sorry about your lost footage. I hope you can shoot it again to your satisfaction. Not to ha ...

Yes I will order some now. I guess the two 16 GB (instead of one 32 GB) is probably the way to go, even though this costs a bit more.

NickTony Posted at 2016-4-16 02:22
Thanks for the tips.

I reinserted the card into the Phantom, powered it on, waited 30 seconds, p ...

I use an U3 Class 10 Sandisk Extreme Pro 64GB, and I still take the videos off of the SD card daily. It literally takes minutes, so why wait until you get a full SD card and then something like this happens? Just be more diligent in the future about removing what's on the SD card more often.

NickTony Posted at 2016-4-16 01:46
Yes, I always power down the Phantom first. I did lose RC signal at one point, which triggered RTH ...

Your supposed to stop recording and exit out of FPV view BEFORE you turn off the aircraft or the video will 1. not record to your SD card, or 2. not show up in your flight logs in the app (the video log). Yesterday, after I launched, 10 seconds after i pressed record, my app and tablet crashed, so I decided to bring it down and land it back. This original 10 seconds of footage was not recorded because I landed and powered down the aircraft before the app could come back up on the tablet. If your really powering down your Phantom before you stop video, you won't get video. Test it out.

FatedFilmsNC Posted at 2016-4-16 20:56
Your supposed to stop recording and exit out of FPV view BEFORE you turn off the aircraft or the v ...

I never power down the drone until I have stopped recording video. I'm not quite sure where you got the impression I did otherwise. But it's good to know what to do in the event that my app crashes. :-)

FatedFilmsNC Posted at 2016-4-16 18:38
I use an U3 Class 10 Sandisk Extreme Pro 64GB, and I still take the videos off of the SD card dail ...

I was having frequent video glitches on both the iPad and on the video written onto the SD card while using the 16GB card that came with the P4. It would freeze and resume seconds later. I then replaced the card with a 64GB Sandisk Extreme Pro and made a full test run with a lot of quick movements to try to duplicate the problem. I switched to sport mode to really test it and the video stream to the iPad never glitched at any distance or maneuver and when I downloaded the video to my PC it was flawless. I HIGHLY RECOMMEND THIS CARD.. I only wish I had it in my P4 this afternoon when I was trying to shoot some cool footage that we traveled to get.

motocam Posted at 2016-4-17 14:12
I was having frequent video glitches on both the iPad and on the video written onto the SD card wh ...

I recently purchased some more Lexar cards, but decided to get the 32GB ones as they actually have double the write speed than the 16GB version. I haven't yet had any glitches (that I can recall) with the 16GB one, but it's good to know it's a possibility.

UPDATE: I was using the data recovery program to scan the WRONG SD Card! For some bizarre reason I thought I had used the 32GB Sandisk card (which I scanned last night), but in fact I was using the 16GB Sandisk card instead. So now some (not all unfortunately) of the 4K footage I thought I had lost has now been recovered!

Which software did you use for recovery?

Geebax Posted at 2016-4-15 23:37
'That reminds me, don't listen to the replier about calibrating. Whenever you move to a location that is not the last location you were at, CALIBRATE THE COMPASS! Don't know where people are pulling the BS that it doesn't matter because they've been doing it for a year.'

Don't listen to this guy, the issue of compass calibration is something he does not understand. The only reason to re-calibrate is because of differences in the magnetic field of the earth from place to place, and it does not actually change that much, only a degree or two here and there, and that will not affect the operation of your aircraft to any significant degree.

Exactly... I have been flying pro for about 3 years and can count on one hand (actually 2 hands and feet for my P3A...) the number of times I have had to recalibrate my P4P, Spark and now Mavic Air... And often times if I ever get that message it is because I am trying to launch directly next to my truck... if I move 10 ft away the notice goes away... like the myth about balancing props... geez... have you ever seen those videos of guys who chop off an inch from a prop... video looks fine with no wobbles or any indication of anything being wrong... with an inch missing from a prop... and people are worrying about their props being .05 gram heavy on one side... and the cubans killed Kennedy -   

FatedFilmsNC Posted at 2016-4-16 02:56
Your supposed to stop recording and exit out of FPV view BEFORE you turn off the aircraft or the video will 1. not record to your SD card, or 2. not show up in your flight logs in the app (the video log). Yesterday, after I launched, 10 seconds after i pressed record, my app and tablet crashed, so I decided to bring it down and land it back. This original 10 seconds of footage was not recorded because I landed and powered down the aircraft before the app could come back up on the tablet. If your really powering down your Phantom before you stop video, you won't get video. Test it out.

It's not that it won't record to your card... it records as it flies... the issue is that it won't "close" the file... so putting the card back in and power cycling the bird and app will do that for you... when it happened to me in my early days of flying (more than once I fear to say...) I also used to record 10 sec of video - just to force the issue... "insert sd card, power up bird/app, it closes previous file. I record new file, stop recording new file, power off"
Aloha