iMovie very slow to render

Discussion in 'Digital Video' started by AndyThomsen, Apr 12, 2014.

  1. AndyThomsen, Apr 12, 2014
    Last edited: Apr 12, 2014

    AndyThomsen macrumors newbie

    Mar 24, 2013
    Hi all,

    I have been using iMovie for a while now, while it took a little while to export (render) in the past, now a 3minute clip takes an hour and a 6minute clip takes 2 hours! I thought it should be 1.5 - 2x longer not 20x longer.....

    All other operations seem as fast as usual even in iMovie.

    Is there some sort of cache i need to empty?
    My CPU is running 2 cores at 80-90% and 2 cores at 30%

    iMac 3.06Ghz i3
    16Gb Ram
    ATI Radeon HD 4670
    OSX 10.6.8

    iMovie 11 - 9.0.4 (1634)

    500Gb HD - 240Gb free

    I have repaired disk permissions, could this have changed something?

    Please help, I'd hate to render a 20 minute video right now.

  2. daybreak macrumors 6502a

    Sep 4, 2009
    Are you using the new version of iMovie. When they upgraded to Maverick they introduced a new version of iMovie.
    Are you using a external hard drive for your video clips?
  3. AndyThomsen thread starter macrumors newbie

    Mar 24, 2013

    I use internal HD only, external is for back-up only.
    My version of iMovie has no new updates, I'm running iMovie 11 - 9.0.4 (1634) as stated in my original question.
  4. daybreak macrumors 6502a

    Sep 4, 2009
    Sorry Andy, did not look at your thread correctly. There are two operating version of iMovie running on 10.9.2. Did you by any change load the new free version unto your Mac?
  5. AndyThomsen thread starter macrumors newbie

    Mar 24, 2013
    daybreak, you are confusing me. It's imovie 9.0.4 and OSX 10.6.8

    Rendering a 1.18 minute video now and it's taking 16-17 minutes, very slow.
  6. AndyThomsen thread starter macrumors newbie

    Mar 24, 2013

    Can no one help me or offer a solution/something to try?

    3 minute video taking 50 minutes to render.
  7. AlainaR macrumors newbie

    Jun 10, 2014
    Your export time might have something to do with the size of the source footage that iMovie is trying to render out. What codec are your source files in? A tool that might help is Edit Ready, made by my company Divergent Media. A workflow that seems to speed up the process is to transcode your files before you bring them into iMovie, which has been known to help reduce the time that iMovie has to take exporting, because it doesn't have to transcode AND export at the same time. Edit Ready can quickly and easily transcode your source files into a native editing codec for iMovie. The codec that I use is ProRes 422LT, it preserves image quality without outputting massive file sizes. You can test this workflow by downloading a free trial of Edit Ready at

    Hope this helps, let me know if it works. :apple:

Share This Page