5.1 over HDMI?

Discussion in 'Apple TV and Home Theater' started by billabong, Mar 8, 2008.

  1. billabong macrumors 6502

    Jan 7, 2004
    Does the DD 5.1 work over a HDMI connection?

    What if there is no receiver involved and the HDMI goes directly to the TV? Will you still get audio, just down converted to stereo?

    How does it work exactly?
  2. Cave Man macrumors 604

    Cave Man

    I don't think many TVs can decode Dolby Digital or DTS, which is why you also need AAC. You cannot even passthrough DD from the ATV to the TV, then from the TV to a DD receiver. That's why we have HDMI from our ATV to our TV and our Toslink to our receiver.
  3. almostinsane macrumors regular

    Feb 9, 2008
    A crap load of TV's decode Dolby Digital and a lot more can pass it through to an AV receiver.
  4. McGiord, Mar 8, 2008
    Last edited: Jan 30, 2011

    McGiord macrumors 601


    Oct 5, 2003
    Dark Castle
    I have a Sony TV with 3 HDMI inputs, I connected my DVD player with HDMI up-conversion to my TV and the sound was included, also my TV has the optical audio out, so I can send the audio to any other device.
    HDMI is like DVI + the audio.
    Also some of the HD shows out there broadcast with DD 5.1.
    I'm not sure about the :apple:TV I don't have one.
    Toyota TF102 history
  5. Cave Man macrumors 604

    Cave Man

    HDCP digital rights prevents it. In most instances TVs can only pass DD from their ATSC tuners, not as passthrough from another HDMI device.
  6. Cozmo85 macrumors regular

    Oct 2, 2007
    My LG 47" lcd passes 5.1 through just fine.
  7. Cave Man macrumors 604

    Cave Man

    Really? You have a device, such as an ATV or DVD player connected to your TV by an HDMI cable, and then another HDMI or optical cable connected from your TV to a Dolby Digital receiver and you're getting passthrough? That would be a violation of HDCP terms, I would think. My Samsung LCD TV doesn't do this (it's 2 months old), thus we have HDMI and RCA cables from our ATV and DVD player, respectively, to the TV, and Toslink and coax to our Onkyo receiver for DD.
  8. billabong thread starter macrumors 6502

    Jan 7, 2004
    So if I rent and HD movie w/ 5.1 DD, and I have my AppleTV hooked up to the tv via HDMI will I get sound out of my TV?
  9. mallbritton macrumors 6502a

    Nov 26, 2006

    You probably won't get DD 5.1, but you will get sound. HDMI does carry audio.

  10. Cave Man macrumors 604

    Cave Man

    Yes. The HD downloads with Dolby Digital come with two audio tracks: AC3 for the Dolby Digital and AAC for conventional analog audio (up to 5-channel Dolby Pro Logic II). The ATV2 software is able to assess your system for the presence of (1) a DD receiver and (2) whether the file has an AC-3 track. If both conditions are met Quicktime on the ATV2 uses the AC3 track for audio. If only one is met (or neither) then you get AAC audio (which is also the default audio track). See here for a little more info on HD DD downloads.

    If you connect your ATV to your TV by an HDMI cable, your TV should be able to decode it even if it isn't DD-capable (because the ATV will only send it the AAC audio). If you connect your TV to a Dolby Digital receiver it is unlikely to passthrough the AC3 track from the ATV2. I have yet to see a TV that does this as it is apparently a violation of digital rights. Others claim their TVs do this, but I am highly suspect of that. It is for this reason why you should connect your ATV directly to a DD receiver using a Toslink cable - it guarantees that you can send the AC3 audio to your Dolby Digital receiver for 5.1 surround sound.
  11. billabong thread starter macrumors 6502

    Jan 7, 2004
    Now how about the 5.1 files created with VisualHub? I think they only contain one track right? So if I play one of those through my TV w/ HDMI I will get no sound then? Or will it downconvert the audio to 2.1?
  12. patrick0brien macrumors 68040


    Oct 24, 2002
    The West Loop

    In order to get the HDMI cert, 5.1 has to be supportable.

    the trick is to decode, and deliver. Obviously, you cannot deliver if you don't have the speakers. So your TV will mix the channels, but will tend to downvolume the rears.
  13. Cave Man macrumors 604

    Cave Man

    I think VH only puts in the AC3 track. If this is the case, and your TV does not have Dolby Digital decoder you will get static. This is what happens with my Samsung LCD TV. It has no DD decoder and when there's only one audio track (AC3) I get static on my TV's speakers.
  14. billabong thread starter macrumors 6502

    Jan 7, 2004
    I really hope that visual hub at AAC+AC3 just like Handbreak does as I have two different TV's one AppleTV is hooked up just via HDMI and can only output Stereo while the other is hooked up to a surround system...
  15. Cave Man macrumors 604

    Cave Man

    My understanding is that VH does one or the other, but not both.
  16. billabong thread starter macrumors 6502

    Jan 7, 2004
    Yeah, would be nice if they added an option for both

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