We have been asked by a client to create a ProRes QT file (.mov) but specifically asked to "The moov atom (movie index file) should be placed at the beginning of the file." I have been reading around but could not find a solution for .mov files. Everybody is talking for .mp4.

The line I came with is:

ffmpeg.exe -i input.mov -c copy -map 0:v:0 -map 0:a:6 -map 0:a:7 -movflags faststart output_ATOM.mov

The audio mapping and the video copying is working fine. I need to know if the -movflags faststart is actually going to do the job? I can't find a way to check the result if it actually moved the Atom.


1 Answer 1


Yes, it does. During the process, you should see the line below near the end of ffmpeg's logging.

Starting second pass: moving the moov atom to the beginning of the file
  • Thanks Gyan! And is there a way to actually check the result if it has the moov atom at the beginning?
    – Yannis
    Commented Apr 15, 2020 at 16:39
  • See stackoverflow.com/q/56963790
    – Gyan
    Commented Apr 15, 2020 at 16:48
  • Thanks but I get a 'grep' is not recognized as an internal or external command, operable program or batch file. Any idea?
    – Yannis
    Commented Apr 15, 2020 at 16:58
  • Which OS are you on?
    – Gyan
    Commented Apr 15, 2020 at 18:04
  • Also, I found another way of checking. Open the mov file with a hex editor and the moov should be at the start.
    – Yannis
    Commented Apr 16, 2020 at 8:12

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