Audio Tracks in m4v's playing oddly, have one question I could really use help on :)

Discussion in 'Apple TV and Home Theater' started by 3282868, Apr 26, 2011.

  1. 3282868 macrumors 603

    Jan 8, 2009
    Last question I swear! lol

    After weeks of HB'ing my DVD rips into m4v's, I've noticed/learned that OS X Quicktime X or 7 do not process AC3 very well (VLC seems to be the only media player that does).

    I have been encoding my m4v's audio w/ AC3 only tracks:

    1. AC3 (5.1) / AC3 / 6-Channel discrete / 48Hz / 640
    2. AC3 Passthru
    3. AC3 DD / Stereo

    I thought this would "future proof" my DVD's to near lossless quality so that I can toss them. However, I learned "AC3 Passthru" is all that is needed as 6-Channel discrete at higher kbps adds nothing to the audio. However, using AC3 for all my audio tracks has produced m4v's that crash Quicktime X or produce movies with severe static no matter what audio track I select. In some cases OS X forces an m4v to be played in QT 7.

    I've used Subler to alter the tracks, turning some off/on. Below is a pic of Subler with an m4v encoded w/ 3 audio tracks; 1 − 6-channel discrete, 2 - AC3 Passthru, 3 - AC3 Stereo. I noticed that 2 - AC3 Passthrough, lists 2-channels:


    *I renamed the audio tracks in Subler improperly as I thought the third audio track was the director's commentary as it listed 2 channel audio for tracks 2-3 but track 2 should be AC3 Passthru
    *Also, the video tracks had "Unknown" for language which I changed to "English"

    Is that correct as I thought AC3 Passthru/through was passing the audio untouched, almost lossless.

    I encoded an m4v that was having audio issues and used this setup:

    1. AC3 Passthru
    2. AAC Stereo

    It played fine on my Mac Pro in all applications. Is this ALL I need for audio, nothing else, and it will play full surround on my Pioneer VSX-33 (which handles all my m4v's on my aTV 2 with no issues)?

    Thanks to everyone who has put up with me over the past few weeks and has taught and helped me so much! :)
  2. omni macrumors 6502

    Jan 20, 2008
  3. 3282868 thread starter macrumors 603

    Jan 8, 2009
    You'll laugh at me, but everything lol. My aTV 2 (JB with XBMC and my aTV 2 connected via ethernet/SMB to a second "Time Capsule", using its 2TB HDD for media). Basically I want to keep the highest quality and I don't care about space/size of the file(s). As long as I can play the m4v on my aTV 2, iPad, iPhone, and Mac Pro I should be set.

    Thanks for any help! :)
  4. omni macrumors 6502

    Jan 20, 2008
    You are one of those people who can't just leave options alone aren't you? Tell the truth.

    I've ripped all of mine using default appletv preset and they play fine on appletv, iphone, ipad and even mac.

    stop messing with stuff.
  5. 3282868 thread starter macrumors 603

    Jan 8, 2009
    LOL I did use the batch encode workflow but the m4v's weren't that great on my 50" Pioneer Elite. I spoke w/ a lot of members, and learned about custom coding for the Handbrake CLI, but the codes weren't taking so I settled for the GUI and used this in advanced settings:

    I spent a lot of time researching on B-Frames, Adaptive Direct Mode, Subpixel ME & Mode Decision and how they effect each other and the m4v. There is a significant difference in image quality using that code. All the m4v's play perfectly, only having audio issues in Quicktime X and 7 in both Snow Leopard and Lion (developer here). XBMC allows me to change audio tracks with no issue, using HDMI from aTV 2 to my Pioneer Elite VSX-33 (it handles all devices through HDMI (including 3D) and outputs via 1 HDMI to my 50" Pioneer Elite). The pixel/picture difference between the aTV/batch setting and my custom settings very apparent on my 50" system. The only issue is audio, which has always perplexed me. I've read up on all the various codecs, AC3 Passthru being one most recommend, although AC3 (5.1) w/ 6-channel discrete at 640 kbps does sound slightly different, and a few DVD's have DTS which sound great! (these are all SD DVD's btw).

    I just need to know if I am choosing the correct audio layers in the correct sequence. I assumed more is better as I can chose which layer per setup as long as it's encoded. Yet if AC3 (5.1) 6-channel discrete at 640 kbps is not better/the same as AC3 Passthru I might as well forego 6-channel discrete and use AC3 Passthru w/ the second being AAC stereo for OS X. Some also claim that placing the stereo track first is important.

    There are so many options and opinions it's frustrating when you're trying to ditch your physical media when there remains one last factor. The video is fantastic, just audio tweaking. Otherwise, everything else is golden :)

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