Dolby TrueHD - how to do it

[bitmonkey]

I'm planning a linuxmce install and want the MD in the lounge (just an MD, core will be elsewhere) to be capable of Dolby TrueHD, which is uncompressed audio which exceeds the bandwidth of S/PDIF - the only way to get TrueHD as I understand it is to use HDMI 1.3a compliant devices and cables so the audio is passed over the HDMI cable along with the video, which I like the idea of anyway as less cables can't be a bad thing. The audio will then be DAC'd on my AV receiver and a HDMI passthru will take the video on to the TV.

I'm planning on using an Abit AN-M2HD as the board for the lounge MD, but this would need to change if this board cannot do audio over HDMI as TrueHD is a requirement.

I have read http://wiki.linuxmce.org/index.php/Audio_over_HDMI and also http://ubuntu-ky.ubuntuforums.org/showthread.php?p=6714092

I'm normally pretty technical, but my media-fu is poor and I don't know my way around ALSA all that well, so I'd appreciate a couple of pointers if anyone can assist.

It looks like alsa 1.0.19 and kernel 2.6.27-11 are prerequisites - I'm pretty sure these will be newer than the 710 release of linuxmce - I don't mind building a new kernel and alsa, but it also occurs to me that the alpha2 candidate of 810 has been out a few months now - what is it's status, is it fairly stable and usable? If that did it out of the box and there were no major stability issues I could probably cope with running the alpha.

Any advice greatly appreciated - I feel a bit out of my depth here as I've never built a media box before and all the little dependencies and compatibility issues seem like they can easily catch you out - ideally someone will reply saying they've done exactly what I want to on the exact same board then I can go ahead and order it, but for now I'm going to hang back to ensure I've got everything covered.

Thanks

Paul

[geekyhawkes]

I dont have an answer to most of your questions as i am just installing 810 alpah 2 now (my first mce), but i will report back.

You might want to have a look here http://forum.linuxmce.org/index.php?topic=8305.0

as i have been able to get hdmi audio and keep the spdif outputing which might help with your setup.

[bitmonkey]

Thanks for your reply,

So with the card and device entries, you just get them from the aplay output and put them in the asound.conf?

Now if someone can confirm they have done sound over HDMI on an Abit AN-M2HD that would confirm it.

I'd definitely appreciate if you'd report back on your experiences with 810.

thanks

[merkur2k]

I have been running 0810 alpha now for a couple months and havent had any problems at all. I am not using hdmi audio.
Dont get too hung up on this "TrueHD" stuff, sounds to me like its more audiophile stuff than anything that matters (would you be able to tell the difference in a double blind test?).

[bitmonkey]

Thanks for the info on 810, sounds like I'll be running that.

TrueHD probably does make a noticable difference, I've never heard it but then it's like people who say they can't hear the difference between say 192kbps mp3 and uncompressed PCM, I have tested double blind on that and certainly can hear, so I'd expect TrueHD is to DTS as PCM is to mp3. I'm a little bit of an audiophile, but you won't catch me buying magic cables or any other hocus pocus, however compressed DTS against basically zipped PCM sounds like a worthwhile upgrade to me.

Incidentally I found this thread on another forum which is very informative, based on the contents of it I have pretty much decided to suck it and see - if the AN-M2HD is not good for sound over HDMI I'll sell it and buy one that is, but this thread seems to suggest that it's not an insurmountable issue in most cases. Here's the link: http://www.nvnews.net/vbulletin/showthread.php?t=97993&highlight=hdmi+audio

[colinjones]

0810, latest nVidia drivers and ALSA drivers, and I'd imagine you will be fine. The board uses ALC888/MCP67 which is well supported. Search for Totallymaxed's comments on the subject as his team already has HDMI Audio working in 0810.

[bitmonkey]

Thanks Colin, I'll search for Totallymaxed's posts - I have also been able to confirm via email with a poster on another forum who has exactly this board that nvidia drivers 180 or newer (I believe back to 177 work too based on my reading) and alsa 1.0.19 or newer fix it and that sound over HDMI is therefore confirmed to work on the AN-M2HD and, as you said, probably anything else using this chipset.

It was a bit of a maze to find clear information, but hopefully this thread will help anyone else considering this board to decide.