Resolved HB'ed m4v's crash QT SOLVED: QT/OS X needs AAC Stereo track, AC3 5.1 needs tweaks

Discussion in 'Apple TV and Home Theater' started by 3282868, Apr 25, 2011.

  1. 3282868, Apr 25, 2011
    Last edited by a moderator: Apr 26, 2011

    3282868 macrumors 603

    Jan 8, 2009
    Some of my HB'ed m4v's are crashing QuickTime X and 7 (VLC is fine), and some research turned up that it may be due to one or more audio tracks being tagged with improper language codes or more than one audio track referenced causing QT to crash.

    Comparing working and non-working m4v atoms, I found atoms for the working track were 0x15c7 versus 0x55c4 for the m4v's that crashed (code follows the ISO 639 language codes, splitting 16 bytes into three 5 bit blocks w/ each representing the letter of the country code, etc.). I need to mention that many of my m4v's have 2-3 audio tracks:

    1 AC3 Passthu (or 6-channel discrete)
    2 AC3 stereo
    3 AC3 for directors commentary or such

    I've tried Subler to fix the issue, and noticed there are more audio tracks than I set in Handbrake. I attempted to fix it by checking the needed audio tracks (and noticed I can rename each layer) in Subler and yet they still crash. Now I'm getting CVDisplayLink crashing.

    How do I remux the m4v so that QT X and 7 default to the correct audio track when played? I know how to select "Language" in QT, but I cannot seem to check any of the tracks listed (and some only list 2 or so audio tracks).

    Thanks for any help!
  2. Sedulous macrumors 68020


    Dec 10, 2002
  3. 3282868, Apr 25, 2011
    Last edited by a moderator: Apr 25, 2011

    3282868 thread starter macrumors 603

    Jan 8, 2009
    Yup, I just edited my post. You've helped me out before, thanks mate. These m4v's are ones I encoded in Handbrake then used MetaX to tag. They play perfectly on my aTV 2, but on my Mac Pro some are a disaster. I definitely noticed QT X and 7 crash as they do not know which audio layer to reference. In one m4v that crashes, the sound is either high crackling or only playing in the left speaker. In that m4v, the first audio layer (example Name=6-channel, Language=English) initially had Language=Unknown. I changed that value to "English" and still didn't fix it.

    Sorry for the trouble, and thanks again for your help! Wish I could repay you for your help!

    Crash report that stood out after console log analysis:

    The above is just one error. I removed all the plugin codecs from /Users/User Account/Library/Quicktime and the movie opened with loud crackling but video was fine. I then selected the second language track which caused this crash (which I have received before and seems to be the prominent issue):

    Here's what I see when opened in Subler:

  4. Sedulous macrumors 68020


    Dec 10, 2002
    Hey, no problem.

    The crackling happens for reasons unknown to me. I have started to wonder if there is a mismatch between frame rate and the audio. Next time it crops up, I will set up Handbrake with a specific frame rate instead of auto (default).

    A temporary solution is to use subler to disable troublesome tracks.
  5. 3282868, Apr 26, 2011
    Last edited by a moderator: Apr 26, 2011

    3282868 thread starter macrumors 603

    Jan 8, 2009

    Researching I learned that OS X will not play AC3 Passthrough (there seems to be many mixed experiences with QT/iTunes versions and AC3 playback, some having to modify the cod3.a52…. file and AudioMIDI app).

    For some reason a good deal of my m4v's from Handbrake all use AC3:

    1. AC3 6-channel discrete 48 640
    2. AC3 Passthru
    3. AC3 Stereo 44.1 256

    Not smart. Should be:

    1. AC3 Passthru
    2. AAC Stereo

    No need for 6-channel discrete as AC3 Passthru is all that is needed, and AAC is necessary for OS X stereo playback (and I doubt AC3 is necessary for stereo).

    Quicktime X cannot handle AC3 which is why my m4v's with AC3 were forced to QT 7. VLC can handle all the m4v's I made without blinking, so can my aTV 2 with XBMC. However, I need to be smart as I'm ditching all my physical media and want all the m4v's produced to be as lossless and flexible as possible.

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