CONCLUSION IS THIS: FASTER IS NOT BETTER BECAUSE THE MAX BITRATE IS 60000kbs.
ANY MICRO SD CARD ABLE TO SUSTAIN 8MB/S IS GOOD ENOUGH.



while i cant complain of the lexar 16GB mini sd card which came with the drone, i noticed the card itself is pretty slow: 10MB/s opposite to 90MB/s on pretty affordable mini sd card (Kingsotn has 60MB/s, Sandisk and Samsung have 90MB/s).
1. is there a setting to adjust the witing/transfer rate to the card's rated speed?
2. is there a way to make the camera aware, like a write test to allow the camera increase the speed on faster cards?
3. anyone using a faster sd card with noticeable improvement in picture quality?
i am using a 90MB/s write card, but the 4k videos are recorded at 8MB/s, same as with the original lexar.

UPDATE JAN 27:
I see that while people who answered are mostly using fast cards, fact is the P4 writes to the card at a very low speed.
I calculated under 8 MB/s, while the cards used by people who posted so far can be written at speeds of 60MB/s to 90MB/s.
Essentially my question to DJI is can the camera adjust to faster speeds instead of high compression, now that the cards allow it?
(faster writing speed on the card would greatly improve image quality , while high compression of data reduces the image quality)

The speed of writing to the card is determined by how fast  the camera writes - not the number on the card.
A faster card won't write faster in the Phantom.
A faster card won't magically make your picture quality any better - either your photos are good or they aren't.
The only benefit would be faster copying to your computer.

You have to be careful with the quoted speeds of SD cards.
The makers love to quote the read speed (because it's faster).
The 16GB Lexar card that DJI supply is not particularly slow.
It has a 95MB/s read speed, and its write speed is 25MB/s.

Mine was supplied with a 16g sandisk extreme.

fans5dc1fe48 Posted at 2017-1-24 03:36
Mine was supplied with a 16g sandisk extreme.

DJI have supplied a number of different brands.
I got a Panasonic.

There is more then just speed in matching cards to cameras. DJI uses U1 cards and Yuneec uses U3 cards. I do not know if DJI can use U3 cards. I have a trail camera that takes the slowest cards available, if you use a faster card the camera freezes after the first frame.

I have the Sandisk Ultra Pro 64GB and it handles everything I throw at it. I interchange it between my Chroma and P4 with no issues. I remove all files and data when switching birds.

fans31e679eb Posted at 2017-1-24 09:20
There is more then just speed in matching cards to cameras. DJI uses U1 cards and Yuneec uses U3 cards. I do not know if DJI can use U3 cards. I have a trail camera that takes the slowest cards available, if you use a faster card the camera freezes after the first frame.

I got a Panasonic 16gb U3 with my P4P from DJI.

I try insert a Lexar 200gb and not recognize. I use same sd in inspire 1 and working well.

fans800f605e Posted at 2017-1-27 09:21
I try insert a Lexar 200gb and not recognize. I use same sd in inspire 1 and working well.

far as i am concerned, capacities larger than 32GB are not recommended on P4. However, I use a 64GB and so far had no issues, although I have to say I havent got to fill it up yet. People also reported using 128GB without issues of capacity. only issues i am aware of are that some cards would freeze after starting to record, while some people say image is pixelated, but i guess that is due to live feed and not related to memory card.

I got a Sandisk Extreme with my P4 and a Sony with my P4P.
Regarding what cards to use, always stick with good brands.
As for the writing speeds, I think the camera of the craft writes at a maximum rate of 10MB/s, anyways I believe it won't matter to get faster speeds except for the speed advantage of copying the files from the card to your PC in which case the the Read speed of the card is the main factor.

Sorry. Mistake. I try use 200Gb Lexar not in P4 but in Inspire 2. In Inspire 1 work well.

The P4 specification recommends 64GB maximum:-

Supported SD Cards
Micro SD
Max capacity: 64 GB
Class 10 or UHS-1 rating required

Better to have lots of smaller memory cards I would have thought, rather than risk losing hours of video on one card should that card fail or get lost. And having several 16GB cards would mean less chance of being without one when needed. Change battery , change card.

Labroides Posted at 2017-1-23 19:45
The speed of writing to the card is determined by how fast  the camera writes - not the number on the card.
A faster card won't write faster in the Phantom.
A faster card won't magically make your picture quality any better - either your photos are good or they aren't.

what i meant is just plain simple: the drone writes at 8MB/s while the card can be written at 90MB/s. if the drone would write faster (say at 80 MB/s) then the image quality would improve dramatically. magically, if you prefer. by a factor of 10. question was is the drone capable at writing faster or not?

WindSoul Posted at 2017-1-28 13:03
what i meant is just plain simple: the drone writes at 8MB/s while the card can be written at 90MB/s. if the drone would write faster (say at 80 MB/s) then the image quality would improve dramatically. magically, if you prefer. by a factor of 10. question was is the drone capable at writing faster or not?

I thought I answered these questions plain and simple back in post #2
I'll try to make it even clearer .....

The Phantom doesn't write any faster if you put the fastest, most expensive card in it.
and
The card is a digital device - it just writes a series of zeros and ones.
There is no way that the speed of the card can make any difference to image quality.

Labroides Posted at 2017-1-28 14:11
I thought I answered these questions plain and simple back in post #2
I'll try to make it even clearer .....

I think what WindSoul is not fully articulating, is that a lower compression ratio on the video would result in better quality, but would require a higher writing speed. He explained this better in another thread.

I know on the P3, you can't control the compression of the video going to the card, though you can control the compression going over the Lightbridge to your mobile device, not sure if the P4 has settings for compression.   Unless the drone has a huge video buffer to capture an entire recording session, it would need a higher speed card to keep up with the writes to the card for the live video.  I doubt that's only 10MB/s
Looking at my video files, none are any bigger than 4.1GB which I believe is the file size limitation of EXFat.  The video lengths of the files that are around 4GB vary from 9 minutes to 21 minutes so obviously the bit rate does vary and so then the compression as well.  I suppose then the drone does buffer the entire video to memory before transferring to the card and card speed could affect how fast the drone completes the transfer.

DanMan32 Posted at 2017-1-28 18:53
I know on the P3, you can't control the compression of the video going to the card, though you can control the compression going over the Lightbridge to your mobile device, not sure if the P4 has settings for compression.   Unless the drone has a huge video buffer to capture an entire recording session, it would need a higher speed card to keep up with the writes to the card for the live video.  I doubt that's only 10MB/s
Looking at my video files, none are any bigger than 4.1GB which I believe is the file size limitation of EXFat.  The video lengths of the files that are around 4GB vary from 9 minutes to 21 minutes so obviously the bit rate does vary and so then the compression as well.  I suppose then the drone does buffer the entire video to memory before transferring to the card and card speed could affect how fast the drone completes the transfer.

There is no video buffer at all in the aircraft. Actually, it is near impossible to provide a buffer for video, you can do it for still shots, and they usually do. The size of the still buffer determines how many shots can be taken in a burst sequence.

But for video, if the card or transmission system cannot keep up with the video stream coming out of the vision processor, having a buffer will never help, because it has no way of catching up. It makes sense when you think about it.

The average speed of the video stream in a P3 Standards is 40 Megabits/second, the P3 Pro and the P4 is 60 Mb/s, and the P4 Pro is 100 Mb/s. Therefore card speed is an issue. DJI started out recommending a Class 10 card when they released the P3 Standard, but since then that specification has become too slow, particularly now the P4P runs at 100 Mb/s.

DanMan32 Posted at 2017-1-28 18:53
I know on the P3, you can't control the compression of the video going to the card, though you can control the compression going over the Lightbridge to your mobile device, not sure if the P4 has settings for compression.   Unless the drone has a huge video buffer to capture an entire recording session, it would need a higher speed card to keep up with the writes to the card for the live video.  I doubt that's only 10MB/s
Looking at my video files, none are any bigger than 4.1GB which I believe is the file size limitation of EXFat.  The video lengths of the files that are around 4GB vary from 9 minutes to 21 minutes so obviously the bit rate does vary and so then the compression as well.  I suppose then the drone does buffer the entire video to memory before transferring to the card and card speed could affect how fast the drone completes the transfer.

the live feed is not really that critical, you only need to be able to understand what you see. but the compression rate determines the write speed on the card- assuming the card supports it.
if you download a video file from card to pc and go to check the details of the video, you can see a bit rate of around 60000kbs, which means under 8MB/s. for a 4k video that is indicative of a compression rate of actually more than 80:1.
however, considering that the current cards can support write speed of 90MB/s, imagine the jump in quality if the compression rate decreased 10 times.

If you read my second paragraph of my last post, I did indeed analyze the details of the video files transferred from the SD cards, and the bit rate was different for two files yet same resolution/frame rate.  Therefore the compression is variable.   I found that ExFAT can handle files above 4GB, the limit being 16 Exabytes, which doesn't make sense since the volume limitation is 128 Petabytes.

It is not impossible for the AC to have a video buffer.   RAM is cheap so a 2-10GB buffer in RAM would not be unheard of.   Do recall that the manual says if you think you lost the last video because you powered off/pulled the card out too soon, to put the card back in and power on the AC within 24 hours of shooting.   Being they indicate to power on within 24 hours, the RAM buffer probably  has an internal battery or multi-farad capacitor backup.

DanMan32 Posted at 2017-1-29 15:34
If you read my second paragraph of my last post, I did indeed analyze the details of the video files transferred from the SD cards, and the bit rate was different for two files yet same resolution/frame rate.  Therefore the compression is variable.   I found that ExFAT can handle files above 4GB, the limit being 16 Exabytes, which doesn't make sense since the volume limitation is 128 Petabytes.

It is not impossible for the AC to have a video buffer.   RAM is cheap so a 2-10GB buffer in RAM would not be unheard of.   Do recall that the manual says if you think you lost the last video because you powered off/pulled the card out too soon, to put the card back in and power on the AC within 24 hours of shooting.   Being they indicate to power on within 24 hours, the RAM buffer probably  has an internal battery or multi-farad capacitor backup.

"Do recall that the manual says if you think you lost the last video because you powered off/pulled the card out too soon, to put the card back in and power on the AC within 24 hours of shooting.   Being they indicate to power on within 24 hours, the RAM buffer probably  has an internal battery or multi-farad capacitor backup."

That's because a sudden power down while recording means that the file cannot be properly closed down. It was the case if the card were placed back into aircraft and powered up then the firmware would close down the file correctly making it viewable.

Now I'm terrible for just shutting down my Phantom 4 without stopping the recording. But I've noticed on the P4 (All latest firmware/software) that when I switch off battery it can take several seconds to shut down (with the switch LED flashing). I have assumed that because I've always been able to view my video files, that the system will automatically close video file on SD card before powering down battery.

You can determine if the issue is indeed a case of closing the file or if it is stored in a buffer by running chkdsk.  If it indicates unallocated chains in FAT and the chain is big enough to account for the video size, then you may be correct.   However even in that case the SD table would have to be cached.

AlecW Posted at 2017-1-29 16:05
I'm bad at that too, in fact I can't remember ever turning off video before shutting down the phantom.  I've got several minutes of exciting video of me walking back to the house and sitting the equipment on the kitchen table

" I've got several minutes of exciting video of me walking back to the house and sitting the equipment on the kitchen table "

Similar here heading back to take off point (The P4 'box'). I'm usually just glad that it's back in one piece.
I've had several 'Alfred Hitchc0ck' moments where you see a shadow clasping the P4 from the sky

EDIT:- That was close the system software wouldn't allow me to post that film directors name

DanMan32 Posted at 2017-1-29 15:34
If you read my second paragraph of my last post, I did indeed analyze the details of the video files transferred from the SD cards, and the bit rate was different for two files yet same resolution/frame rate.  Therefore the compression is variable.   I found that ExFAT can handle files above 4GB, the limit being 16 Exabytes, which doesn't make sense since the volume limitation is 128 Petabytes.

It is not impossible for the AC to have a video buffer.   RAM is cheap so a 2-10GB buffer in RAM would not be unheard of.   Do recall that the manual says if you think you lost the last video because you powered off/pulled the card out too soon, to put the card back in and power on the AC within 24 hours of shooting.   Being they indicate to power on within 24 hours, the RAM buffer probably  has an internal battery or multi-farad capacitor backup.

Please, there is no buffer, period. If you know anything about recording video, it is not possible to have a buffer for an open-ended video event. It is OK for stills because the approximate file size of a still is known, but for video that is not the case. Any buffer would eventually be over-run by the process. It has got nothing to do with the cost of RAM.

And the file issue is simply that the process records a stream to the card, and when you finish recording, it has to finalise the recording and terminate the file. If that process is not done, the file does not even appear on the card, so it is possible to over-write it the next time you press record. However if you place the SD card back in the aircraft, or leave it there, and power cycle the aircraft, the file will be finalised and able to be seen and read.

Sure it can buffer, as long as it has enough RAM to do it just as there needs to be enough storage on the SD card to hold the video file.  RAM and SD card are essentially the same thing with RAM being much faster.
After all there is a limit to how much video you can possibly record based on max possible flight time, and the size of storage you need just multiply by max bitrate.
Even a small SSD storage could be used, although in that case you would have an indefinite period of time to recover.
Now if you were doing a live stream of indeterminate period of time, then you could get a buffer overrun if your end storage could not keep up.   But even live stream on a PC is buffered by a few minutes in RAM.

DanMan32 Posted at 2017-1-29 15:34
If you read my second paragraph of my last post, I did indeed analyze the details of the video files transferred from the SD cards, and the bit rate was different for two files yet same resolution/frame rate.  Therefore the compression is variable.   I found that ExFAT can handle files above 4GB, the limit being 16 Exabytes, which doesn't make sense since the volume limitation is 128 Petabytes.

It is not impossible for the AC to have a video buffer.   RAM is cheap so a 2-10GB buffer in RAM would not be unheard of.   Do recall that the manual says if you think you lost the last video because you powered off/pulled the card out too soon, to put the card back in and power on the AC within 24 hours of shooting.   Being they indicate to power on within 24 hours, the RAM buffer probably  has an internal battery or multi-farad capacitor backup.

bitrate is the only indication of compression in a file. far as i could see there are no files with bitrate above 60000kbs. that is a meager 8MB/s. whether there is a transfer buffer or not is DJI secret and therefore irrelevant. I asked a simple question: is there a way to increase the bitrate, yes or no? keep it simple sunny.
but since youre after the technicalities, let me put it on special order for you: do they use USB3 for the micro sd or are they using the USB2? obviously the USB3 is more than able to sustain high transfer rates, while USB2 would be the bottleneck.

WindSoul Posted at 2017-1-29 18:22
bitrate is the only indication of compression in a file. far as i could see there are no files with bitrate above 60000kbs. that is a meager 8MB/s. whether there is a transfer buffer or not is DJI secret and therefore irrelevant. I asked a simple question: is there a way to increase the bitrate, yes or no? keep it simple sunny.
but since youre after the technicalities, let me put it on special order for you: do they use USB3 for the micro sd or are they using the USB2? obviously the USB3 is more than able to sustain high transfer rates, while USB2 would be the bottleneck.

'but since youre after the technicalities, let me put it on special order for you: do they use USB3 for the micro sd or are they using the USB2? obviously the USB3 is more than able to sustain high transfer rates, while USB2 would be the bottleneck.'

The DJI aircraft do not use USB anything for storage, the SD card interface is built into the vision processing chip and does not get strangled though a serial interface.

And No, there is no way to increase the bitrate, it is determined again by the vision processing chip, which is not a DJI product. It is a third party device designed to handle all the vision processing, streaming, SD card interface etc.

I have not looked inside the P4 or P4Pro, but the P3 aircraft used the Ambarella chip, which you can look up on-line if you want to know its capabilities.

I did forget to divide by 10 (rough conversion between bits and bytes).
My point about buffering to RAM first is on account that I don't think the compression/bit-rate is determined until after the video is completed and then transferred to the card.
However the bitrate/compression could be dynamic and variable where the information given in the file detail is an average.

My longest recording is 21:34 with a file size of 4.1GB but I have other files a few megs bigger but only 9 minutes long.  It is as if the system is making sure the file is within the 4GB limit normally imposed on FAT32.
Seems if you keep your individual recordings at or below 9 minutes at a clip, you stand a better chance of higher bitrates and less compression.  No guarantees though.

DanMan32 Posted at 2017-1-29 19:23
I did forget to divide by 10 (rough conversion between bits and bytes).
My point about buffering to RAM first is on account that I don't think the compression/bit-rate is determined until after the video is completed and then transferred to the card.
However the bitrate/compression could be dynamic and variable where the information given in the file detail is an average.

'I did forget to divide by 10 (rough conversion between bits and bytes).'

Actually, it is 8.

'My point about buffering to RAM first is on account that I don't think the compression/bit-rate is determined until after the video is completed and then transferred to the card.'

Again, totally wrong. The compression is performed inside the vision processing chip. There is no RAM buffer (again). You really have no idea about MPEG compression and how it is achieved. It is done in a hardware MPEG coder inside the vision processing chip, and the average bit rate is hardware determined.

So what is the verdict? Any difference in video quality between 80 and 90MB/s when recording in 4K?

fans843702c8 Posted at 2017-8-21 00:06
So what is the verdict? Any difference in video quality between 80 and 90MB/s when recording in 4K?

Read post #2 again

Forgive me but the posts were getting a little technical for me.

I disagree with the conclusion, Faster is always better, I purchased this Micro SD Card http://amzn.to/2x51IGc Yes it is overkill for the Drone however what the huge benefit is that the transfer time from memory card to computer is greatly reduced. I can transfer 20GB of footage in a few mins, some not as fast cards take 10+ mins.  for the small amount of money extra its much better getting a faster card http://amzn.to/2x51IGc

Bradders Posted at 2017-8-21 00:22
I disagree with the conclusion, Faster is always better, I purchased this Micro SD Card http://amzn.to/2x51IGc Yes it is overkill for the Drone however what the huge benefit is that the transfer time from memory card to computer is greatly reduced. I can transfer 20GB of footage in a few mins, some not as fast cards take 10+ mins.  for the small amount of money extra its much better getting a faster card http://amzn.to/2x51IGc

That's a good point you make.

With the transfer over a USB3 port being substantially faster than that of USB2 (in theory 10x faster). So a faster memory card on a USB3 port can make a real difference. The biggest step of course is making sure that it's the USB3 port on computer being used, most computers having a mix of both types. The USB3 being marked with a blue coloured plastic tab in socket or plug.

Edit:- Based upon what is a minimum required for the aircraft to record successfully, then the original conclusions were not wrong. Buying 'The best of the best' memory can be very expensive compaired to what is actually needed (which is not what you did).

Aardvark Posted at 2017-8-21 00:34
That's a good point you make.

With the transfer over a USB3 port being substantially faster than that of USB2 (in theory 10x faster). So a faster memory card on a USB3 port can make a real difference. The biggest step of course is making sure that it's the USB3 port on computer being used, most computers having a mix of both types. The USB3 being marked with a blue coloured plastic tab in socket or plug.

Thank you, Yes a Faster is better as transfer times are significantly improved, If your a MacBook owner any Mac 2013 or newer is USB3.0 so with a SD Card reeder or inbuilt reader you will see the full speeds and get the advantage of the high speed memory card.

You say the card is really expensive, but when I spent £1000+ on a drone, £20 is not much for a good memory card considering recording is the primary purpose of the drone. http://amzn.to/2x7axz0

Bradders Posted at 2017-8-21 13:22
Thank you, Yes a Faster is better as transfer times are significantly improved, If your a MacBook owner any Mac 2013 or newer is USB3.0 so with a SD Card reeder or inbuilt reader you will see the full speeds and get the advantage of the high speed memory card.

You say the card is really expensive, but when I spent £1000+ on a drone, £20 is not much for a good memory card considering recording is the primary purpose of the drone. http://amzn.to/2x7axz0

My bit in brackets excluded you from buying the most expensive.

Here's a good example though of the lengths to which one could go.