Strange mp4 problem

Discussion in 'Digital Video' started by portreathbeach, Jul 1, 2012.

  1. portreathbeach macrumors member

    Joined:
    Feb 19, 2011
    #1
    I have been converting mkv files with Handbrake to mp4 (or mv4) for iTunes so I can use them with my Apple TV. Everything works pretty well apart from a few......

    Some of the mp4 files have a strange problem. They play fine on my desktop, but when they are copied to my Qnap NAS, they cannot be played and QuickTime doesn't recognise it as a valid file format. If I then copy the mp4 back to my Desktop from the Qnap, it still doesn't play!!!

    What can be going wrong when I am just simply copying from my Mac to my NAS?

    I also copied a couple of movies from youtube, both downloaded as mp4 files and only one of them can be copied to the NAS device and played, the other has the same error!!!
     
  2. MisterMe macrumors G4

    MisterMe

    Joined:
    Jul 17, 2002
    Location:
    USA
    #2
    Sounds like you are copying the "._" files rather than the actual video files.
     
  3. portreathbeach thread starter macrumors member

    Joined:
    Feb 19, 2011
    #3
    I am definitely copying the correct files. They are between 700Mb and 4Gb in size. It's strange, as it only does it with some of the files. I copy to the NAS, it is unplayable. On the ones that don't work when copied to the NAS, I use Subler to repackage the original mp4 file on my Mac and export to the NAS and it works fine.

    Can't understand why it is only some of the mp4 files and not all of them.
     
  4. HobeSoundDarryl macrumors 603

    HobeSoundDarryl

    Joined:
    Feb 8, 2004
    Location:
    Hobe Sound, FL (20 miles north of Palm Beach)
    #4
    How is the Qnap formatted? What file system?

    Are the files that are failing when copied back, would they happen to be bigger than 4GB files (and are the ones that are working when copied back <4GB file sizes)?

    If it's not file sizes, can you identify any other commonalities for the problematic files? Odd file names? Anything else?
     
  5. portreathbeach thread starter macrumors member

    Joined:
    Feb 19, 2011
    #5
    I have had the Qnap for 3 or 4 years, can't remember what the disks are formatted too, but they are in mirroring mode. I have never had any problems with files over 4Gb on the drive or any other problems in the past.

    It can't be a file size problem, as a couple of the mp4 files that were causing the problem are between 500-700Mb in size.

    All of my files are encoded with Handbrake on 'High Profile' setting. So all the video outputs are the same mp4 and audio has AC3 passthru and remuxed Dolby Pro Logic. They all work fine when playing from the desktop. I can't understand why simply dragging them to the NAS makes them unplayable. As previously stated, it only happens with a few of them.

    I'm not sure if the file names may be causing a problem. I'll wait till I get another one that doesn't work and see if there are any strange characters in the file name.
     
  6. HobeSoundDarryl macrumors 603

    HobeSoundDarryl

    Joined:
    Feb 8, 2004
    Location:
    Hobe Sound, FL (20 miles north of Palm Beach)
    #6
    Take note of the file size before you copy one of the problematic ones over to the QNap. Then, when you copy it back from the QNap see if it is the same file size.

    If some are working and others are not, this is probably NOT the problem. But good to rule out.
     
  7. portreathbeach thread starter macrumors member

    Joined:
    Feb 19, 2011
    #7
    Been converting a few more mkv files to m4v and then putting them onto the NAS device. Can't replicate the error again.
     

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