Jerky Quicktime playback on mac pro 3.2 Ghz

Discussion in 'Mac Pro' started by wizb98y, May 28, 2009.

  1. wizb98y macrumors newbie

    Joined:
    May 4, 2009
    Location:
    San Diego, CA
    #1
    I generated a full HD 1920x1080 mp4 video file and tried
    playing it back using Quicktime. The playback was very jerky.
    The same file played beautifully using VLC. So I don't think
    it is cpu horsepower issue. Anybody have similar problem
    playing back mp4 HD materials using Quicktime? Any ideas?

    mac pro 3.2 Octo with 10 GB Mem and 4.5TB diskspace.
     
  2. TheStrudel macrumors 65816

    TheStrudel

    Joined:
    Jan 5, 2008
    #2
    What compression settings were you using? Quicktime is better optimized for some things than others.
     
  3. wizb98y thread starter macrumors newbie

    Joined:
    May 4, 2009
    Location:
    San Diego, CA
    #3
    I was using the standard H.264 HDTV 1080p 29.97 preset in the Adobe
    encoder (VBR, 1 pass, target 32, max 40 mbps). I also tried using
    24fps, same problem. What I don't understand is that VLC played
    the same files very smoothly - doesn't VLC uses/shares the underlying
    decoders OSX provide to Quicktime. Granted, I am just speculating as
    I don't know how these things work.
     
  4. grue macrumors 65816

    Joined:
    Nov 14, 2003
    Location:
    Somewhere.
    #4
    QuickTime sucks harder than a sorority girl on a friday night. God only knows why.
     
  5. TheStrudel macrumors 65816

    TheStrudel

    Joined:
    Jan 5, 2008
    #5
    Actually, I don't think quicktime does use the same decoder. But it's worth pointing out that you can optionally install a different decoder - I can't remember where from - that might perform better. Quicktime's performance does leave something to be desired. That's something that could benefit from some GPU acceleration (especially now that most cards support HD decoding of one sort or another in hardware...but probably not in OS X).
     
  6. elvisizer macrumors 6502

    Joined:
    May 29, 2003
    Location:
    San Jose
    #6
    it'd be helpful to know more about the actual h.264 settings the adobe encoder is using. quicktime tends to choke on some high profile specific features- pyramidal b-frames, or just too many b-frames in the first place are two that'll make it choke.
    do you know what settings the encoder used?

    also, VLC uses it's own decoder, not quicktime's, and doesn't have these issues with high profile h.264
     
  7. davidfastolfe macrumors newbie

    Joined:
    Jun 30, 2009
    #7
    I have the exact same problem, I can play my HD MP4 video in VLC but the playback jerky in Quicktime. No matter how the MP4 is encoded, Quicktime is unable to correctly play HD MP4.

    I will not spend my time looking for a new codec or whatever it takes to correct this problem. If Quicktime can't play it well I will be using HDTV MPEG 1080p or WMV.

    One more thing. From Itunes you can convert MP4 to M4V The playback is perfect then. But it's 720p not 1080p Depending on your needs it can be an option.
     

Share This Page