5 Replies Latest reply: Nov 25, 2012 8:04 PM by AppleMan1958
Robert Lesperance Level 2 (340 points)



Before creating a video in iMovie, I got different MOV files from friends and familly.  When I import those MOV files in iMovie, a copy is saved in the iMovie event folder, but the file size increases substantialy.  Here are example:


  • an original 16MB MOV file becomes a 323MB MOV file
  • an original 4MB MOV file becomes a 42MB MOV file
  • an original 174MB MOV file becomes a 246MB MOV file
  • an original 3MB MOV file becomes a 37MB MOV file
  • an original 307MB MOV file becomes a 370MB MOV file
  • an original 31MB MOV file becomes a 114MB MOV file


Why does my files increase so much in size ?   Should I keep the original or the iMovie event version for later use ?

Joyful owner of an iMac Intel ... Fast as light !!! !!!!, iMac Intel - 3,06 GHZ - 21" - 12.0 Go
  • AppleMan1958 Level 7 (27,415 points)

    See this post for why the files get bigger.



    I would keep the events for as long as you are editing these projects. After that, you can keep the original. You can always reimport it if you need it.

  • Robert Lesperance Level 2 (340 points)

    Thanks AppleMan 1958 ...  That is a complete a clear answer. 


    I have imported old super 8 film into DV format.  They now take alot of space (500GB).  If all complete events are inserted in my iMovie project, could saving it in the highest resolution prevent me of keeping my originals for further use ?

  • AppleMan1958 Level 7 (27,415 points)

    My suggestion is that you only want to import those 8mm tapes once, so you want to keep them.

    Your video files are stored in the Events. The project file contains a text file that has the paths and file names and in and out points of the clips you use in the events. If you delete your events, your projects will no longer work.


    Once you Share a completed project, you have a finished movie, so in theory, you could delete the event and project after that, but that would prevent you from ever using this footage again.


    I suggest getting a large external disk drive and moving them there.


  • Robert Lesperance Level 2 (340 points)

    Is there any file format that, fully compressed, keeps the full possible resolution of a DV format ?

  • AppleMan1958 Level 7 (27,415 points)

    In the case of DV, it is already a full-frame codec, so the files do not get any bigger on import. But DV is plenty big, nonetheless.


    You can SHARE the finished movies using SHARE/EXPORT MOVIE or SHARE/to iTUNES in Large or Medium size. This will be an h.264 file and will be much smaller. It will look quite good on playback. You will only find a problem if you have to uncompress it so you can edit it further.


    H.264 is fine for playback of your finished movie. Only you can decide the value of your raw footage.