Detecting "fast start"


  • Anonymous

    I've noticed that most "fast start" .m4v files I encounter place the MOOV atom name at bytes 37-40 but this isn't universal.  For example, Handbrake seems to favor bytes 32-35.  So, does the standard reserve a starting position for the MOOV atom or is it simply relative to (e.g. comes right after) the ftyp atom that precedes it?

    Trying to write a simple AppleScript droplet to detect whether a ,mov or .m4v or .mp4 file is quick start or not.

  • atnbueno

    I don't know about the standard, but if you run the following you'll get where the moov is:
    AtomicParsley videofile.m4v -T | grep moov

    Does it helps?

    P.S. I've checked with a few hundred videos and I get either a 32-byte offset or a huge one.