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So any way to prevent video file split at 4gb?

Discussion in 'Pro/Adv Discussion' started by alirz, Jan 26, 2016.

  1. alirz

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    As the title says. Is there a way to avoid having video file sutomatically split once it hits 4GB file size. My SD card is in exfat format but that doesnt avoid the problem. Is it simply in the drone's firmware to start a new file at 4GB.

    problem is that even if i join the split files. There is like 1 sec of video missing at the join point.
     
  2. bbfpv

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    exFAT supports files > 4GB. If you truly think your card is exFAT and that the firmware is cutting off the files at 4GB, a simple test would be to stick the card in your computer and try copying a file > 4GB. If it doesn't work, then the card wasn't formatted using exFAT.
     
  3. ianwood

    ianwood Taco Wrangler
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    P3 cuts files at 4Gb regardless. No workaround.
     
  4. rockydog

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    I'm surprised you're losing a second between files...in FAT32 there's no loss of frames between the files.
     
  5. alirz

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    yeh i porbably should test with fat32...
    I formatted my card exfat in windows several weeks ago. Since then the DJI go always displays "suggest to format SD card" while its recording video.
    well, if exfat is not working around the 4gb limit, then i might as we go back to fat32 and as you said perhaps i wont have missing frames....
     
  6. alirz

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    well i had posted the same question on DJI's forum. Someone replied. I cant tell if he's a DJI rep or just a user.
    DJI Forum|Any way to prevent video file split at 4gb?

    His statement:

    Unfortunately, our video processor does split video files near the 4GB file limit of FAT32, even if using a 32GB or 64GB SD Card formatted as exFat (FAT64).
    I'm sure there is some write buffering while the new file is created but there can be a loss of frames if you're using slower write speed SD cards. As a best practice for now, we must understand this design and plan our shots accordingly. If possible, you can correct in post-processing as needed.
     
  7. Consultant

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    Can you please explain how this can be fixed in post processing? The problem is a loss of data. You cannot create frames in a motion video that you don't have. So therefore there will always be a skip. The only real "fix" would be to cut to a different scene before the skip in my opinion but that's not a fix for the problem.
     
  8. Drestin Black

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    Files are cut at 4 Gb to remain compatible with multiple operating systems.

    However, there is no gap between the files. The output is buffered and during the minuscule time it takes to close then open a new file, the data flow is buffered in memory, in the same buffer that is used during all video file output.

    If you have a gap it's the fault of whatever software you are using to join. The files I have joined are without a single missing frame.


    Sent from my iPad using PhantomPilots
     
  9. Consultant

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    I use Davinci Resolve which is used by major motion picture companies. Maybe the break in the files was during little movement in the shot so you didn't notice?

    I am sending you a link so you can download the raw files from the SD card from Dropbox. I very much look forward to seeing the edited video you create without the skip!

    Here's a snippet that came out of Davinci for comparison:



    It there is truly no lost frames, this would be FANTASTIC to learn!

    Also, what brand/model of SD card are you using? There was rumor that could make a difference but it has not been shown to be true.
     
  10. Consultant

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    Nope. I'm 100% sure it's not the video editing software. I loaded the MOV files from the SD card into PowerDirector 15 instead of Davinci Resolve and as I suspected there are indeed missing frames. Other users have reported DJI Support responded "This is normal." and have eluded to the fact other action cams have the same issue. However not all action cams have the issue so it IS fixable.

     
  11. tcope

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    The Phantom's firmware only writes in FAT. exFAT on SD cards is proprietary and requires a royalty payment. As such, it's not a 100% standard.
     
  12. Consultant

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    Good to know. Thanks. I could care less if DJI fixes the issue by supporting exFAT or fixing the firmware so it buffers properly. Either will fix the issue and I'm sure they can afford the royalties.
     
  13. Drestin Black

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    Hate to disagree brotha but:
    Phantom 3 and 4 (and Mavic) supported file systems are: FAT32 ( ≤ 32 GB ); exFAT ( > 32 GB

    ExFAT is proprietary and owned by MS who licenses it to MANY people, it is the defector standard to use on SD cards and must be used on SD cards >32 GB in capacity.

    If you use a card of capacity other than the max, 64 GB it's for stated in FAT, UNLESS it was already formatted in exFAT, in which case that format is retained when reformatting. 64 Gb cards ALWAYS format into ExFAT, or they couldn't hold 64 GB.

    Having said all that, let me address our missing frames issue, but I'll do that in the next post


    Sent from my iPad using PhantomPilots
     
  14. Drestin Black

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    I see it and it's huge! I have joined many files and not seen this. I can produce an example for you to see.

    Let me address this fully, combined with my reply to tcope above. Due to a bug in the PhantomPilots forum app I have to split my message here, I'm sorry, reply follows in next post.




    Sent from my iPad using PhantomPilots
     
  15. Drestin Black

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    ExFAT is very cool. It is everything FAT should have been. Not only for handling larger capacity but because it was designed for the particularities of SD cards/drives AND it can handle very high speed streaming of data with very low overhead. For example, it can pre allocate space to a file and bypass updating the actual FAT until idle. ExFAT is what you want if you are capturing streams of data such as streaming video at up to 60 mbs

    I am using a P4 with a 64 GB card using ExFAT, it's a class 10 card from Sandisk. No skipped frames.

    May I ask, what type of SD card (class), capacity, fat or ExFAT formatted, which drone and what capture spec (1920x1080@30 FPS for example)

    If you have a 32 Gb card formatted using FAT and capturing 4K video at 30 FPS, that could very well be overrunning both the device/os record speed and software buffers.


    Sent from my iPad using PhantomPilots
     
  16. Drestin Black

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    Here is one simple suggestion to try. Format your SD card on a Mac or (preferred) PC using ExFAT then put it into the drone and try again.


    Sent from my iPad using PhantomPilots
     
  17. Consultant

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    This just in from DJI Support:

    "I do understand that at certain point, there is a skipped frame when you are attempting record a video.

    The reason for having it set on this file saving orientation is because it is for file safety and security. Instead of having your video saved in a continuous frame, it is segmented every 4GB so that in an event of power surge or power failure, you will still have a file that you can recover compared to a total loss of the whole footage.

    We can forward your feedback to our Developers to further study this case and in future development it may be available in the succeeding firmware update though this is may not be the case. We are also crossing our fingers that they can accommodate most of our valued customer's feedback and suggestion."
     
  18. tcope

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    Let me be more clear. You can format the SD card FAT, FAT32 and exFAT. However, the _firmware_ only supports 4GB files. The _firmware_ is the limiting factor. Formatting has nothing to do with this. The firmware limits the file size to the lowest format possible which is FAT.
     
  19. kennedye

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    Are you using a fast enough SD card?
     
  20. Drestin Black

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    Inaccurate. Yes they sent that message to someone but I can promise you if you wanted to do that your do it far far smaller increments and not the universally accepted place to do it for OS compatibility lol that email is a line of crap.