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GoPro cuts 4K video in two

Discussion in 'Photos and Video' started by dronie, Dec 3, 2014.

  1. dronie

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    Hi,

    I use the HERO4 Black - on a Phantom 2 with Zenmuse H3-3D gimbal - and often shoot in 4K/25.

    But the GoPro cuts the video file in two:
    a) I see this even for a short shot (fx. 14 minutes)
    b) The GoPro is recording prior to take-off, and not touched until stopped after landing.
    c) The SD card is fast enough (Lexar Class 10, 633x (95 MB/s bought from gopro.com)

    This could be an issue if the file is split with dropped frames (which I don't know happens). I thought the video clip length could be minimum as long as the flight of one Phantom battery 15-20 minutes.

    Is this normal - or how can I make sure to get only one file?
    Also, do you know if the GoPro drops a frame or two when spliting the file?

    Thanks.
     
  2. dronie

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    GoPro Support just called me back on this issue so I just wanted to provide the answer myself ;-)

    1) The camera splits up the files automatically and it's a normal procedure - called Chaptering - for a couple of reasons, but one benefit is that if the SD-card gets corrupted, there's a good chance that only the last chapter is lost.

    2) It splits up in chaptering depending on file size, so a 1080p file could be up to 20 min long, and a 4K less.

    3) They where not able to say exactly how big a file could be (or how long) before the file gets split.

    4) It's not possible to change the Chaptering behaviour (i.e. change when it splits files)

    5) There is no dropped frames, so stitching two chapters together in an editor will not cause any issues

    I haven't tested the last claim (no. 5) though, but if you have, please share your experience here.
     
  3. QYV

    QYV

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    You're probably running into a file size limit for the file system of your SD card. If it's a 32GB or smaller card, it's probably FAT32 file system which has a 4GB file size limit. As the gopro is recording, when it hits 4GB it simply creates another file and keeps going.

    64GB cards tend to format with exFAT which can support files over 4GB, and the gopro itself will indeed format a 64GB SD card with exFAT according to this article: http://gopro.com/support/articles/exfat ... patibility
     
  4. traeger23

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    I've seen this happen on the Black 3+ shooting in 2.7K Cine, with clips that ran longer than 15 minutes or so. I never ran into any issues with dropped frames when sequencing the two files together in Premiere. It modifies the name of the second file so that it ends in the same last four digits, so, for example, if the first file is GOPR00123.MP4, the automatically generated second file will be GP010123.MP4. If it stretches into a third file, it names it GP020123.MP4, and so on.

    The initial files all seem to be right around the 4GB file size limit, which was mentioned earlier. I think this is a compatibility issue with Windows systems that might have the 4GB FAT size limit, but I'm not even remotely positive of that. In any case, you can reconstitute a full-length video clip with no dropped frames from the chaptered source files.
     
  5. dronie

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    " In any case, you can reconstitute a full-length video clip with no dropped frames from the chaptered source files."

    Then it's no problem - that was my only concern. And splitting the file up also makes is easier to leave out unwanted footage when picking stuff to transcode to ProRes and thus saving some time.