Puzzled: QuickTime performance on 2008 MP octal vs 2013 MBP

Discussion in 'Digital Video' started by dampsquid, Aug 9, 2013.

  1. dampsquid macrumors newbie

    Jul 23, 2011
    Just got a Gopro (love it) took video (1080 48fps) straight off card and copied to SSD drive on MP. Was surprised playback with QT stutters now and again. Scrubbing in QT is very jumpy. Copied same file to MBP and it's silky smooth, both in x1, faster, and scrubbing back and forth. Can't fault it.

    Looked on Activity Monitor, found some significant differences:

    MP: QT CPU ~18%, VTDecoderXPCService CPU ~130%, Disk read 3-4Mbit/s
    MBP: QT CPU 15-18%, VTDecoderXPCService CPU 0%, Disk Read: 3-4Mbit/s

    when the mbp stutters that coincides with both QT and VTDecoder' utilizations dropping significantly too.

    Any one any idea why I'm seeing this difference in behaviour?

    MP: 2008 8 core, 2.8 GHz, 20GB, SSD boot, SSD scratch (where file is), spinning 'data' drive, HD5870
    MBP: 10,1 2.3GHz i7, 16GB, factory SSD.
  2. acearchie macrumors 68040


    Jan 15, 2006
    Have you tried playing it back in VLC?

    I have had some issues a few times with older CPUs not playing back the video quite as well.

    Are they the same OS and both up to date with software updates?
  3. dampsquid thread starter macrumors newbie

    Jul 23, 2011
    Both machines are up to date on 10.8.4

    VLC works fine on both machines, doesn't stutter on the mp like QT does. That said, it doesn't seem to skim as well as QT does.

    What I'm hoping for is some insight into why the VTDecode... process is running at >>100% on the mp and 0% on the mbp...?
  4. xStep macrumors 68000

    Jan 28, 2003
    Less lost in L.A.
    The MBP is using the GPU while the MP is using the CPU.
  5. dampsquid thread starter macrumors newbie

    Jul 23, 2011
    Thanks for your reply. Can I ask, is that speculation on your part, or do you know it to be so? I wondered about that too -
    Perhaps a remore pertinent question is can the mp be persuaded to use the HD5780?
  6. phoneorpda macrumors regular

    Sep 7, 2005
    All around the world.
    I just had the same issue. has anyone found a solution for this?

  7. gullySn0wCat macrumors 6502

    Dec 7, 2010
  8. Policar macrumors 6502a

    Nov 21, 2004
    I find gopro footage to play back very slowly, too, although the footage I used was 24fps 2.7k. It might be the codec.
  9. phoneorpda macrumors regular

    Sep 7, 2005
    All around the world.
    is there any solution to this in an old MP (2009)?

    every quicktime movie is stuttering and the VTDecoderXPCService process is hogging the cpu down to a crawl!
  10. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California

    QT is using OpenCL. In other words QT is using the GPU if it is available and the CPU otherwise. Your new MBP has a GPU that OpenCL can use.

    You could upgrade the graphic card on the MP to one that is supported by current versions of OpenCL. But the cost is very high. The card costs 1/4 as much as a new MP. You'd be better off selling the old MP and buying the new MP than dumping $1000 to $500 into an upgrade.
  11. Mr. Retrofire macrumors 603

    Mr. Retrofire

    Mar 2, 2010
    QuickTime X does not use OpenCL or Quick Sync to decode the video data streams. QuickTime uses specialized units of the discrete or integrated GPU which decode the video data. That is the reason why QuickTime X supports the hardware accelerated decoding of H.264 data even on older (2009) integrated GPUs, like the NVIDIA 9400M. As you know, the 9400M does not support OpenCL and does not support Quick Sync.

    AFAIK, Apple uses the Quick Sync decoder/encoder unit only for AirPlay video data streams. Nothing else.

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