mkv h264+10.6+9400M+1080p -> The Answer?

Discussion in 'macOS' started by kastiAUT, Jan 18, 2010.

  1. kastiAUT macrumors newbie

    Jan 16, 2010

    There are quite a few threads about stuttering HD mkv's. I don't know it this can help in all cases but it did in mine.

    Problem free HD enjoyment really depends very much on the bitrate of the mkv. Many mkv's will play nicely in any player, but if the bitrate goes up to 20Mbit/s, all players struggle. My iMac with nVidia 8800+3.06Ghz dual core can not handle those with any player. My MBpro5,5 has an even harder time. The best experiences I have are with plex and Enhanced mplayer (enable multi threads). But even they struggle in critical scenes. BTW, this also applies to any windows PC unless the GPU supports the CPU. The CPU alone just can't handle it.

    Luckily for 10.6 users + 9400M chipsets and newer, apple included GPU acceleration for QuicktimeX. Unluckily, QuicktimeX does not use GPU acceleration for mkv's (actually, Quicktime does not support mkv's at all unless you install perian).
    If you get the GPU to support the CPU, the CPU load drops from maxed out to below 15% for exactly the same video stream.

    Here is how to do it:

    1. Download avidemux2 (freeware, 2.5.2 is the current version). I think you will need perian (A52 codec) if you want AC3.
    2. Open your video in avidemux2
    3. set video and audio to copy (If you don't need AC3, I would use AAC since quicktime supports it better)
    4. set the format to mp4
    5. Save the video: if you got AC3 in the mkv, a warning appears that result might be unplayable. AC3 has only been added to mp4 standard recently, normally you have to use AAC. Ignore warning.
    6. Video/Audio will be put into mp4 container. This takes a few minutes. No transcoding happens, only copying (passthrough). Therefore, quality will not be affected, output video will be the same size as original.
    7. If you got AC3 in the stream, quicktimeX will not be able to open the video. The problem here I think is with the A52 codec in perian. You need to open QuicktimeX in 32 bit.
    8. Enjoy video stutter free at 15% CPU.

    BTW: this only works for h264 coded mkv's which I guess are most.


    P.S.: You can do all of this also in Quicktime7 pro if you got it. Export the video to mp4, set video passthrough and audio to AAC. You will loose surround in this case however.
  2. Gav2k macrumors G3


    Jul 24, 2009
  3. SHADO macrumors 6502a


    Aug 14, 2008
    Yea same here I just use VLC on my 15" MBP and 720p and 1080p resolutions work very well. Even output to 1080p HDTV's works well with no stuttering.
  4. Inconsequential macrumors 68000

    Sep 12, 2007
    VLC works but its not perfect.

    Not even on my Mac Pro!
  5. DoFoT9 macrumors P6


    Jun 11, 2007
    nice intent there Herbert, but im not sure that you've done everything correctly to get playback working.

    your 3.06GHz iMac struggles? i find that quite disturbing. on my CoreDuo 2.16GHz MBP, i can playback 1080p rips perfectly using Plex. they hit >100mbit in some scenes!!

    VLC is not exactly the best coded app out there, its cross-platform and disgusting to use. plex is purely for mac and is actually written quite well. the CPU can handle BDs nicely without the need for GPUs - however it is nice that you have posted this information :)
  6. kolax macrumors G3

    Mar 20, 2007
    Wouldn't it just be wonderful if all video formats were GPU accelerated on the Mac and we got h.264 feeds of YouTube rather than Flash.

    Don't I wish..
  7. DoFoT9 macrumors P6


    Jun 11, 2007
    doesnt "ClickToFlash" allow you to load only the h264 youtube movies or something? i thought that it did.

    GPU acceleration of all codecs would be AMAZING. :(
  8. kolax macrumors G3

    Mar 20, 2007
    Well reminded, forgot about that wee plugin.
  9. DoFoT9 macrumors P6


    Jun 11, 2007
    its a great little thing!

    clicktoflash combined with squidman (proxy server) makes quite a fast web browsing experience! :D
  10. Corrode macrumors 6502a


    Dec 26, 2008
    Calgary, AB
    1080p mvk's play fine on VLC for me. Actually they were much smoother after 10.6 came out.
  11. nonnynz macrumors newbie

    May 24, 2008
    Thanks Herbert, that's very handy. Excellent when using a Mac Mini or Macbook to drive a secondary display. Even more useful for me when taking the Macbook over to the TV and running off battery power - much more power efficient.

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