No AC3/DTS pass-through via SPDIF out - half solved

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Franko30
Posts: 6
Joined: Fri Apr 30, 2010 5:46 pm

No AC3/DTS pass-through via SPDIF out - half solved

Post by Franko30 »

Hi,

I got my fitpc2i this week and finally had the time to install Ubuntu 9.10 according to this guide:
http://www.fit-pc2.com/wiki/index.php?t ... buntu_9.10

Everything works fine, video acceleration works fine (although with some 720p material I have lots of artifacts in mplayer), analog audio works fine with standard analog connection cable via SPDIF out and cinch adaptor.

The problem however is digital audio via SPDIF with the connector cable that was delivered with the fitpc2i:

I have "digital" sound when switching the audio properties of Ubuntu to "Digital Stereo (IEC 598) output + Analog Stereo Input".

But I did not find a way to get correct AC3/DTS pass-through (my receiver shows me once it gets a proper signal - with fitpc2i it always shows "PCM signal" and thus switches to normal Dolby Surround instead of Dolby Digital or DTS).


With my old Athlon XP PC I want to replace with the fitpc2i, I could achieve correct AC3/DTS pass-through in Ubuntu 9.10 by choosing the following settings in mplayer:

* Preferences -> Audio -> alsa audio with "hw=0.2" and
* Preferences -> Codecs & Demuxer -> Audio Codec Family -> AC3/DTS pass-through S/PDIF

Similar settings in fitpc2i's mplayer produce "broken pipe" or "PCM not found" or "no sound" errors (in fact all the hw=0.0, 0.1 or 0.2 produce errors, other audio drivers/system that are available produce errors, too).

Does anybody have an idea how I could achieve correct AC3/DTS pass-through? Watching HD movies without correct Dolby Digital or DTS is no fun...

Cheers

Franko30
Last edited by Franko30 on Fri May 07, 2010 1:13 pm, edited 1 time in total.

Franko30
Posts: 6
Joined: Fri Apr 30, 2010 5:46 pm

Re: No AC3/DTS pass-through via SPDIF out

Post by Franko30 »

Anyone?

Franko30
Posts: 6
Joined: Fri Apr 30, 2010 5:46 pm

Re: No AC3/DTS pass-through via SPDIF out- half solved

Post by Franko30 »

Hi again,

I didn't spend my time waiting, searched other forums and found a clue in the Ubuntu Forum at their website:

When I play a file with the commandline MPlayer (instead of gmplayer), AC3/DTS pass-through via SPDIF out works!

The respective commandlines are

Code: Select all

mplayer -ao alsa:device=hw=0.1 -ac hwdts Filename-with-DTS-sound.xyz
and

Code: Select all

mplayer -ao alsa:device=hw=0.1 -ac hwac3 Filename-with-AC3-sound.xyz
To do this with long directory and filenames is very cumbersome - especially when you have to try for DTS or AC3 everytime you play a file.

Is there a way to incorporate these commandline options (working automatically for DTS or AC3) into the gmplayer configuration file? I couldn't find any way to do this... It only gives me all kinds of PCM not found, etc. errors.

Cheers

Franko30

Denis
Posts: 301
Joined: Sun Apr 26, 2009 3:24 pm

Re: No AC3/DTS pass-through via SPDIF out - half solved

Post by Denis »

Hi,
You can add default settings to /etc/mplayer/mplayer.conf or ~/.mplayer/config.
Compulab's Linux support

Franko30
Posts: 6
Joined: Fri Apr 30, 2010 5:46 pm

Re: No AC3/DTS pass-through via SPDIF out - half solved

Post by Franko30 »

Hi,

Thanks for the reply - but that I knew already (I use Ubuntu since its first version).

My question is how to put the commandline mplayer settings into gmplayer's config file in way that actually works - because

Code: Select all

ao_driver = "alsa"
ao_alsa_device = "hw=xyz.xyz"
a_afm = "hwac3"
doesn't work with fitpc2i and fitpc2i's Ubuntu 9.10 changes (poulsbo/mplayer) - whereas it does on all my other laptops/PCs that run Ubuntu 9.10 or 10.04 - be it internal soundchips/cards (on which ao_alsa_device = "hw=0.2"is the configuration that mostly works for digital output) or external soundcards (on which ao_alsa_device = "hw=1.0"is the configuration that mostly works for digital output).

And there's also the unresolved issue with mplayer's inablity to display OSD or subtitles in fitpc2i's version, see:
http://www.fit-pc2.com/forum/viewtopic.php?f=33&t=1103

Cheers

Franko30

Denis
Posts: 301
Joined: Sun Apr 26, 2009 3:24 pm

Re: No AC3/DTS pass-through via SPDIF out - half solved

Post by Denis »

Hi,
I succeed to enable AC3/DTS pass-through via SPDIF out both in gui and command line interfaces of mplayer:
Command line:

Code: Select all

mplayer -ao alsa:device=iec958 -ac hwac3 Filename-with-AC3-sound.xyz
Gui:
* Preferences -> Audio -> alsa audio with configuration "Device: iec958"
* Preferences -> Codecs & Demuxer -> Audio Codec Family -> AC3/DTS pass-through S/PDIF

Note! Under device menu, in alsa driver configuration, there is no "iec958" entry. You need to write it manually. The existent entries: hw=0.X do not work
Compulab's Linux support

Franko30
Posts: 6
Joined: Fri Apr 30, 2010 5:46 pm

Re: No AC3/DTS pass-through via SPDIF out - half solved

Post by Franko30 »

Hi Denis,

thanks for the answer.

I will test it once I have the time.

Cheers

Franko30

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