What are my audio options over HDMI?

Okay, I'll try and keep this simple.

I've got an Acer Revo 3610 hooked up to an Onkyo HTX-22HDX which has the ability to decode pretty much anything you throw at it. The speaker set is 5.1. I regularly use XBMC 10.1 for file playback and TMT3 for blu-rays (via an external drive).

I'm simply trying to figure out how to get the best audio from each of these sources to the AV amp over HDMI?

• With XBMC, I'm mostly playing my DVD collection so the audio never goes beyond regular DTS soundtracks. I've set the Audio Output Device in XBMC's settings to "WASAPI: NVIDIA HDMI Out" - is this any better/worse than using "Directsound: NVIDIA HDMI Out"?.

• In TMT3 there's no option for WASAPI, but changing the 'Mixing Mode' produces various results. Mixing to PCM, DTS or Dolby Digital shows the AV amp receiving those respective formats, but using "Original Primary Audio only" seems only to send the 'core' part of any HD audio tracks (either DTS from DTS-MA tracks, or DD from DD-TrueHD tracks). What's the best option here? Is mixing to PCM outputting the full uncompressed audio track, or is it being tampered with in some way?

• Finally, what should my Windows audio settings be? My HDMI Out properties show sample rates supported up to 192kHz, but only 'Dolby Digital' as a format [click for image]. Is this a problem?

As always, thanks for the help guys!

Anyone? Even if it's just to point me in the right direction?

Thanks.

Thanks for your reply, jriver. I understand the concept of bitstreaming, but I'm not sure that the ION platform supports bitstreaming of HD audio formats over HDMI. From what I read, it doesn't. I'm just trying to get the best audio out from the Revo, even if that means unpacking to PCM before outputing the audio to my receiver.

Everything 'works' (WASAPI or DirectSound in XBMC, any of the mixing settings in TMT3) - but which settings provide the best audio output? And should I match my Windows audio settings to typical HD soundtracks (16bit / 48kHz)? Is there any advantage to upmixing to 24bit / 96kHz or above?

Thanks, I guess I was more worried about it adversely affecting my audio in some way (because of the extra processing).



It's weird, my windows settings don't show DTS as a supported format, but my receiver displays 'DTS' when playing rips with DTS audio tracks, and will recieve the DTS core track when playing DTS MA tracks in TMT3.

I don't have the latest drivers, but nor do I have really old ones - I got everything working a while back and didn't want to 'mess' with things!



Is this a limitation of TMT? I've read something previously about PCM tracks being downsampled, but could remember if it was TMT or Windows that was to blame.



I do use MPC-HC and this is what I'm going to try next - I've been reading the Advanced MPC-HC Guide here, but that sets you up for bitstreaming. Do I just need to uncheck the 'DTS-HD' and 'Dolby TrueHD' boxes in the LAV Audio Decoder setting page to have it decode them to PCM rather than bitstream?

Thanks for all your help, renethx!