[basic troubleshooting] How can I improve my framerates?

  • Tech Staff

    I am noticing some wild fluctuations between my FPS and apparent choppiness in the video when playing back movies in Isadora, and I feel like I must be doing something wrong or missing something obvious. I have searched around for old threads, but most of the information was rather old.
    Video content are a collection of 40 or so 30-second B&W film clips in .mov format, supplied by the director. We want to be able to mix a few of these clips together randomly and possibly add some interactivity, but right now are experiencing issues with basic playback. None are above standard def resolutions, but some are playing back very choppy in Izzy (framerate monitor still reads a solid 30fps though). In some cases if I try to playback more than one clip, my FPS tanks completely.
    Some clips I'm able to run up to four clips, and the FPS bounces between 17 and 30 fps. What might be causing such a large variances? Shouldn't it either hold solid or just tank?
    Would it be in my best interests to recompress or resample these in another format or codec? If so, which, and what's the more efficient way to do this? I have FCPX, can I fix these clips using it?
    Reading around the forums shows many people able to play back multiple HD videos on lesser machines than mine. What gives?
    I'm working on a fully-loaded macbook pro with retina display, outputting to two stages (projector and HDTV).
    I have options to live capture from a Blackmagic Intensity Extreme with my DSLR. Also in the mix: a Kinect/ni-mate and Touch OSC on iPad.
    I should add that the video clips are living on USB3.0 or Thunderbolt external drives, both @7200 RPM. However, moving the clips onto the SSD hasn't made a noticeable difference.
  • Beta Tester

    What are the encoding settings for the .mov clips? Quicktime movies can be encoded with a wide variety of settings and different ones will behave wildly differently for playback in Isadora.

  • Izzy Guru


    As MatthewH pointed at, the .mov is just a container not the compression format. If you open the files in Quicktime hit "cmd + i" and you will see what format, datarate and framerate the movie has.
    Also check that Isadora matches the framerate of the movie. I can hardly get smooth video playback when the movie has 30fps and Isadora is set to 25fps.


  • It is my recommendation to re-encode the media given by somebody else always. You never know what weird codec from what platform these are put out to.

    For best performance Apple PhotoJPG at 75-85% quality(you can go less to if needed) is recommended with Isdora and most other video apps on mac. PC may be different, don't know.
    Try that first. 
    You can convert with MpegStreamclip that is excellent free app for many basic video tasks(cut-edit and so on).
    I am not sure about FCPX it is so crippled by silly(mainstream media) presets so I never use it.
    BTW You may want to make all the media same size too. Isadora scaling can be pretty troublesome. But for that I would use app where I can control the quality well like After Effects.
  • Izzy Guru

    sometimes you can even have the output stage set to a small resolution (640480 or 320240) and let the projector (assuming its a good one) do the upscaling.

    And yes MpegStreamclip is amazing!