DD 5.1 not working with Mp4 file?

Discussion in 'Apple TV and Home Theater' started by ninethirty, Jan 7, 2011.

  1. ninethirty macrumors 6502a

    Mar 1, 2006
    Hey Everyone,

    I'll keep this brief. I had an 720p MKV file which I used MKVTools to change into an mp4. The video was H.264 so I went passthrough, and the original audio was 6 channel AC3. I converted to 5.1 AAC. When I stream from iTunes to my AppleTV the receiver does not change to a digital format, although I do hear surround channels, but it doesn't sound quite like 5.1 (almost like when Dolby Pro Logic II or something). Any ideas? I have DD turned on in the options, and my system absolutely supports it - I have no problems with my Blu-ray player or my Xbox 360.

    Thanks in advance!
  2. newagemac macrumors 68020

    Mar 31, 2010
    I don't think it supports 6 channel AAC. It supports 6 channel AC3 like was in your original file before you converted it.
  3. ninethirty thread starter macrumors 6502a

    Mar 1, 2006
    I made it 5.1 AAC. Any ideas? I could try the 6 channel AC3, but I only have a 5.1 setup at home...

  4. waw74 macrumors 68030

    May 27, 2008
    5.1 = 5 channels + sub = 5+1 = 6

    most stereos do not support AAC, and the apple TV would have to convert it back to AC3 for your stereo to decode it.
  5. emmgunn macrumors member

    Jul 7, 2008
    Just to summarize, if you want surround sound (6-channels or 5.1, as waw74 mentioned, they're the same thing for our purposes) the only way you can get that with the ATV2 is 5.1 AC3 that is passed through to a surround receiver. So DTS won't work either. I think that you had mentioned that in another thread, so I thought I'd clear that up for you here.

    If you don't need the extra options in the mp4 tab of MKVtools like adding the second audio channel, use the quick tab and MKVtools will figure out the best settings for you. For the file that you mentioned, you could passthru both the video and audio and you should be good.
  6. andre.abreu macrumors newbie


    Jan 11, 2011
    Brasil, Rio de Janeiro
    I have the same problem, AAC multi-channel dont work on my HT (Onkyo HT-RC160) ... I only see the six icons on display when I use AC3 ...

    Because this I convert my movies with two audios! One AAC 2ch for full compatibility with iPad and iPhone and AC3 (Dolby Digital) 5.1 for Apple TV 2!

    I hope to help and sorry for my bad English!
  7. newagemac macrumors 68020

    Mar 31, 2010
    Your English is fine. You just need to use a period instead of exclamation marks to end your sentences. ;)

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