noob HTPC - HDMI 1.3a output for sound??

Discussion in 'Home Entertainment Computers' started by FaxFan2002, Jan 22, 2008.

  1. FaxFan2002

    FaxFan2002
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    Hi,

    Been thinking about a HTPC for a while now. I'm thinking along the lines of...

    HTPC -> Onkyo 805 (HDMI) and TOSlink

    I assume that (ripped) SD DVD's will send video via HDMI and sound via TOSlink and the AMP will take care of everything including the decoding of sound? I ask this as I want to do the decoding rather than the HTPC thus getting best quality sound.

    Next question relates to (ripped) Blu Rays (and I may grab some HD DVD's). I have a PS3 connected to the AMP via HDMI. The PS3 obviously sends (or rather will do once DTS-MA is sorted) the hi-def codecs and uncompressed PCM to the AMP. Is there a way of achieving this on a HTPC?

    I can look into silent running fans / drives etc. or locating in a different room with remote connections / long lead etc.

    Thanks,
     
  2. Wo0zy

    Wo0zy
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    Hi,

    Currently there are no HDMI1.3 solutions for the PC only 1.2. The capabilities of which depend on which solution you go for.

    Both ATi and NVIDIA have solutions that can only pass 2-channel LPCM or AC3 via HDMI (or in most cases DVI converted to HDMI). All 2000 series Radeons support HDMI audio (limited as I just explained) via an onboard sound chip. However this is only activated when you use a specific "ATI Branded" DVI>HDMI converter (a normal one won't work). Only some 8000 series NVIDIA cards can support HDMI audio and those that do don't have a sound chip but a loopback mechanism from your sound card. While this is less elegent it does mean that features supported by your soundcard (DSP, EQ, etc) can be passed to HDMI. Obviously either solution can be used for Video only and you can continue to use your SPDIF connection to an AVR for audio if you wish but if you only store the DD soundtracks for DVD's you may as well use the HDMI for video and audio.

    For HD content (BD or HD DVD) both solutions are going to be rather limiting. If you want to listen to the HD Audio the only way to do this with either ATI or NVIDIA's solutions is to hook up discrete analogue connections from your soundcard to your AVR and have the playback software decode and send the results via the discrete channels. Either that or send 2-channel PCM to your AVR via HDMI (or SPDIF) and use Pro Logic (which kinda misses the point :)). Even going down the analogue route has it's issues. Not only are most sound solutions quite weak on this front you also have to contend with the fact that PowerDVD "downsamples" the audio during the decoding process (for what ever reason).

    There is another solution available today that I haven't mentioned yet and that's Intel's latest IGP (X3500) found on G35 Motherboards. While this lacks the HW acceleration capabilities of both the ATI and NVIDIA solutions it does add the ability to send multi-channel LPCM via HDMI (similar to what you do with the PS3). There are again a number of issues here (including the aforementioned PDVD "downsampling") but this is as good as it gets currently in terms of HD Audio on the PC. Because Intel are "slaves" to EDID some AVR's have problems with this config but nobody (at least to my knowledge) has had problems using this solutions with Onkyo equipment.

    Sorry to ramble on but this is a massive topic and I've hardly scratched the surface. Hope it helps a little.

    Wo0zy
     
  3. FaxFan2002

    FaxFan2002
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    Thanks Wo0zy - very comprehensive answer and just what I was suspecting. I do like the idea of being able to access our vast CD library online rather than looking through a massive pile in the corner but I also want to future proof.

    Would you say with the Intel G35 motherboards is a matter of waiting for the software to "catch up" ?
     
  4. Wo0zy

    Wo0zy
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    Hi FaxFan2002,

    There are definitely driver improvements in the pipeline which should fix some of the "quirks" and add greater control but they won't do anything for the HW Acceleration.

    If you're going to consider it for your platform and want to play HD content then it will need to go hand-in-hand with Vista and a very good (or heavily OC'd) CPU.

    To clarify, HD playback is only supported (and only works) under Vista. There will be HW Acceleration for MPEG-2 once SP1 arrives. There is partial acceleration for VC-1. There is no acceleration for H.264 at all.

    G45 will change this and as it's not that far off (from what I've heard) my worry is that G35 will quickly lose focus. Having said that, overall I think it's currently the best solution for a SFF HTPC.

    Hope this helps.

    Wo0zy
     
  5. FaxFan2002

    FaxFan2002
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    Hmmmm... it certainly sounds like things are changing I think I may hang fire and see what pops up in the next couple of months.

    My fallback would be to use the mac mini for SD DVD's - I can always move them accross at a later date.

    Thanks for all the info!
     
  6. Wo0zy

    Wo0zy
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    No problem mate.

    While the HD Acceleration issues certainly isn't a "deal breaker" with good CPU's being so cheap these days, the addition of HDMI 1.3(a) with the ability to pass HD audio as bitstream would make the purchase far more "future proof" (LoL. I had to use THAT phrase didn't I :D).

    TBH the software side of the HD coin is an even bigger let-down at present. Lets hope that the competition that Arcsoft are bringing to Cyberlink shakes things up!!.

    Cheers,

    Wo0zy
     

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