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Audio format questions

Discussion in 'Apple TV and Home Theater' started by BORIStheBLADE, Jun 15, 2008.

  1. macrumors regular

    BORIStheBLADE

    #1
    So I have a Apple Tv I'm trying to convert my DVD's to a file that can pass the 5.1 AC-3 surround sound through the digital cable to my receiver.

    Right now the only way I can get it to play one the way I like is by using Handbrake. I use the H.264 encoder which saves it as a .M4V and keeps the audio track in AC3. I have a clip from a movie so my conversions are short so I don't have to waist time with test.

    I end up with a file that looks like this.

    General
    Complete name : C:\Users\mike\Desktop\cars1.m4v
    Format : MPEG-4
    Format profile : Base Media / Version 2
    Codec ID : mp42
    File size : 60.4 MiB
    Duration : 7mn 54s
    Overal bit rate : 1070 Kbps
    Encoded date : UTC 2008-06-15 16:02:45
    Tagged date : UTC 2008-06-15 16:11:07
    Writing application : HandBrake 0.9.2 2008022300

    Video
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : Main@L5.1
    Format settings, CABAC : Yes
    Format settings, ReFrames : 1 frame
    Codec ID : avc1
    Duration : 7mn 54s
    Bit rate mode : Variable
    Bit rate : 621 Kbps
    Width : 720 pixels
    Height : 400 pixels
    Display aspect ratio : 16/9
    Frame rate mode : Variable
    Frame rate : 23.976 fps
    Minimum frame rate : 23.976 fps
    Maximum frame rate : 23.988 fps
    Colorimetry : 4:2:0
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.090
    Stream size : 35.1 MiB
    Writing library : x264 core 58 svn-736M
    Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=4 / brdo=0 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / chroma_qp_offset=0 / threads=3 / nr=0 / decimate=1 / mbaff=0 / bframes=0 / keyint=240 / keyint_min=24 / scenecut=40(pre) / rc=crf / crf=25.5 / rceq='blurCplx^(1-qComp)' / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40
    Encoded date : UTC 2008-06-15 16:02:45
    Tagged date : UTC 2008-06-15 16:11:07

    Audio
    Format : ac-3
    Codec ID : ac-3
    Duration : 7mn 53s
    Bit rate mode : Constant
    Bit rate : 448 Kbps
    Channel(s) : 2 channels
    Sampling rate : 48.0 KHz
    Resolution : 16 bits
    Stream size : 25.3 MiB
    Encoded date : UTC 2008-06-15 16:02:45
    Tagged date : UTC 2008-06-15 16:11:07



    Now when I look at that info I see only 2 channels, but when I play it on the AppleTv my receiver shows a digital audio signal and says it Dolby digital 5.1.

    So if it is only 2 channel how am I getting DD 5.1?

    thanks
     
  2. macrumors 68020

    #2
    Trust me, you *are* getting all of the dolby d goodness. The pcm stream simply announces itself as 2 channels. In Quicktime you can see all six channels if you use "SHow Movie Properties" and click on the surround audio track at the top, then at the bottom there is a tab which shows the six channels and their mapping. This is exactly the same scheme as the ATV HD movies from apple.
     
  3. macrumors regular

    BORIStheBLADE

    #3

    Ok, as long as it isn't the fake surround sound I'll be happy.

    thanks
     

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