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**Bahndit** · 2008-12-31, 13:54

From what I understand what we need to figure out is how to get ALSA to pass multi-channel PCM out the HDMI port. FFmpeg currently supports the decoding of Dolby True-HD, although not the ffmpeg libraries currently included in XBMC. When the libraries are updated XBMC will essentially be passing ALSA a multi-channel pcm track just like it is now with FLAC. DTS-HD/MA is another story. The reason that it is working now is because of the way that the DTS-HD codec was designed. DTS-HD is completely backwards compatible with old DTS decoders. DTS-HD/MA tracks have at their core a basic DTS track (lossy) that the codec then builds off of to make the track lossless. That is why the DTS-HD tracks are working for Rodercot. Hopefully in the future we can get native support for all of the HD codecs but if FLAC sounds just as good as the native codecs I would be estatic to get it working. It was mentioned earlier in the thread that ALSA may just need to be configured to get LPCM working. What do I need to do so to see if that is the case?

**rodercot** · 2008-12-31, 14:59

Bahndit Wrote:From what I understand what we need to figure out is how to get ALSA to pass multi-channel PCM out the HDMI port. FFmpeg currently supports the decoding of Dolby True-HD, although not the ffmpeg libraries currently included in XBMC. When the libraries are updated XBMC will essentially be passing ALSA a multi-channel pcm track just like it is now with FLAC. DTS-HD/MA is another story. The reason that it is working now is because of the way that the DTS-HD codec was designed. DTS-HD is completely backwards compatible with old DTS decoders. DTS-HD/MA tracks have at their core a basic DTS track (lossy) that the codec then builds off of to make the track lossless. That is why the DTS-HD tracks are working for Rodercot. Hopefully in the future we can get native support for all of the HD codecs but if FLAC sounds just as good as the native codecs I would be estatic to get it working. It was mentioned earlier in the thread that ALSA may just need to be configured to get LPCM working. What do I need to do so to see if that is the case?

check this link out and see if it helps at all.

http://alsa.opensrc.org/SurroundSound

Dave

**Bahndit** · 2008-12-31, 23:58

Okay well my excitement is a bit diminished since I realized that this changelog (see other post) also aplies to ALSA 1.0.18 So now I need to confirm whether or not the NVIDIA drivers currently support multichannel LPCM in Linux. If so then it is back to .asoundrc for me. Thanks for your work anyways.
In the AVS forum it was suggested that I use PulseAudio to make this happen. What do you guys think?

**BLKMGK** · 2009-01-01, 10:38

Not familiar with using PulseAuduio but know that at least until recently it had issues with XBMC and folks were killing it or removing it (sticky in the Linux forums as a matter of fact) - I've done neither but I am running SVN versions and one of the required packages is libpulse-dev. SVN versions have been tweaked to better work with PulseAudio apparently but I've not run into issues. That said stereo sound for MP3 not working on that box either <ahem>

May be ordering the Asus board for my primary box soon and be able to spend more time troubleshooting...

xanium4332 · (This post was last modified: 2009-01-01, 21:35 by xanium4332.)

Just another 'me too' reply.

Mobo: Asus P5N7A-VM
CPU: Intel E8400 (3GHz)
RAM: 4Gb OCZ Stuff (cheap).

Your guide worked perfectly, thank you. Also note that the graphics drivers don't HAVE to be upgraded, I tried with both the 180.x and 177.x and hdmi audio works fine.

I haven't tried 5.1 LPCM over hdmi (don't have the hardware, but will do), so I'm interested to hear if that works or not.

Also note that sound is output through the DVI port also. I have a DVI->HDMI cable and accidently noticed I got sound when plugged into the board's DVI port.

Again thanks for the guide, James

**alanwww1** · 2009-01-02, 00:52

We will have no help from having Pulseaudio, because it all depends on Alsa. We will have to get Alsa support for HDMI Multichannel LPCM. But i think Alsa devs need help from Nvidia with the implementation.

xanium4332 · 2009-01-02, 03:27

Erm, seems like a version bump (or something) has now caused the alsa-driver patching to fail, any ideas?

(This is on a fresh install, after my previous post).

James

**BLKMGK** · 2009-01-02, 07:18

Why are you patching ALSA?

**rodercot** · 2009-01-02, 15:48

xanium4332 Wrote:Erm, seems like a version bump (or something) has now caused the alsa-driver patching to fail, any ideas?

(This is on a fresh install, after my previous post).

James

I would not play with this, you will break your system. I have another machine running Mythbuntu with the latest SVN compiled yesterday, I also built and installed 2.6.28-ultimate kernel and the latest Nvidia Beta driver of 180.18 and still no luck with lpcm.

You will have to roll back to alsa-1.0.18a it should still be in your /usr/src dir as when it downloaded via the script. just recompile it and reboot with the script and -i

Dave

xanium4332 · 2009-01-02, 17:08

Sorry, I said the wrong thing.

I meant the kernel-snapshot, when being patched during 'sudo make', fails now. Going back and using a snapshot from the 31st solved the problem for me. I'm not sure that the 31st is the last working date, I just knew it was working at that time so picked it.

Sorry about the confusion, James

**rodercot** · 2009-01-02, 17:19

xanium4332 Wrote:Sorry, I said the wrong thing.

I meant the kernel-snapshot, when being patched during 'sudo make', fails now. Going back and using a snapshot from the 31st solved the problem for me. I'm not sure that the 31st is the last working date, I just knew it was working at that time so picked it.

Sorry about the confusion, James

did you happen to run a

apt-get dist-upgrade or the like.

Dave

matyhaty · 2009-01-03, 02:16

hi all

for us lesser mortals, i wonder if someone can help:

im looking for good old basic hdmi audio - for now getting top notch flawless sound is a lesser priority, and i guess for many its the same.

As it happens i do have a very nice bose system, linked to a samsung r700 cinema receiver, but just getting hdmi audio is the main thing for me....

some have said need upgrade graphics, some not
some have done snowflakes stuff (to which i do not understand)

would anyone be able (and kind enough) to write a fools example to the best bet of getting hdmi working, in a basic form, which will play simple movies and mp3s etc.

if the basics are there, maybe it will be in the next release defacto,..,,,.

many thanks

Matt

**rodercot** · 2009-01-03, 12:15

matyhaty Wrote:hi all

for us lesser mortals, i wonder if someone can help:

im looking for good old basic hdmi audio - for now getting top notch flawless sound is a lesser priority, and i guess for many its the same.

As it happens i do have a very nice bose system, linked to a samsung r700 cinema receiver, but just getting hdmi audio is the main thing for me....

some have said need upgrade graphics, some not
some have done snowflakes stuff (to which i do not understand)

would anyone be able (and kind enough) to write a fools example to the best bet of getting hdmi working, in a basic form, which will play simple movies and mp3s etc.

if the basics are there, maybe it will be in the next release defacto,..,,,.

many thanks

Matt

Matt,

I do not have a video card with HDMI out on it that I can test in your configuration. I still think with the cable from the spdif port out on the board to the spdif in on the sound card and then at min 177.82 Nvidia Drivers and you will need the latest alsa for sure anyhow, The combo of the two should force alsa to see the output I would think.

If you look at the Nvidia forums there are possibly some ideas in there as well that could help you out.

Dave

mr_raider · 2009-01-03, 17:16

That's incorrect. The default 177.80 with Ubuntu 8.10 will work fine as long as you upgrade ALSA to 1.018a on the Geforce 8200. I can't speak for the 9300.

There is a simple comand line utility to install nvidia drivers in ubuntu called envyng.

Upgrading the Alsa is easy enough as shown in the first post.

**BLKMGK** · 2009-01-03, 18:37

EnvyNG didn't put in the drivers I thought I needed, I moved to Ubuntu 8.1 to solve that. I then used the repository drivers.... Upgrading ALSA was done via the script highlighted here.

SPID/f cable to port on video card gives you audio yes but of no greater bandwidth than SPID/f would have if run to a receiver so it not exactly the same as what we are talking about here and likely doesn't require the latest ALSA and video drivers to use. It's "cheating" so to speak IMO.