The VideoLAN Forums

Sound card - Abit UA-11, which is "USB-to-S/PDIF" device. Detected as "KC USB Audio Device", module snd-usb-audio.

With Mplayer

mplayer -ao alsa:device-hw=0.0 -ac hwac3, filename.avi
mplayer -ao alsa:device-hw=0.0 -ac hwac3, dvd://

all works just fine - a Dolby Digital decoder connected to the sound card via an optical cable detects AC3 stream.

VLC (0.8.6a) is set to use ALSA and that sound card (in ALSA preferences, hw:0,0). There is "A/52 over S/PDIF" in the menu, so that VLC detects S/PDIF. But whenever I select it, my decoder has no a signal on its input. Just silence.

Messages are full with "main debug: audio output is too slow (-412177), trashing 32000us". As I understand, this is the reason...

All the same with AVI and DVDs.

Fedora Core 6, if it matters, with all the latest updates.

So what can I do do pass AC3 (and, ideally, DTS) stream to the S/PDIF? Please don't offer to stick with MPlayer

One more note: when I choose "A/52 over S/PDIF", VLC shows Mute sign on its volume control. Dunno if it matters...

Exactly the same experience. If you temporarily choose the 'Stereo' audio device....I bet you get sound over your SP/DIF, but it won't include AC3. When it detects A/52....it doesn't work. I've run into a number of people with the same issue....different sound devices...even different kernels. No answer yet!

Same problem here with Linux and VLC Player version 0.8.6c. What I did:

Settings > Preferences > Audio:
- [tick mark] 'Advanced options'.
- [tick mark] 'Use s/pdif when avaliable'.
- Output modules: [pull-down box] Audio output module: 'ALSA'
- Output modules > ALSA: [pull-down box] ALSA device name: 'C-media PCI iec958 hw:0,2'.

No sound through my s/pdif.

What does work:
- The above settings and Right-mouse > Audio device > Stereo. And adjust the sound volume up!

Then I have sound through my s/pdif, however it is "downchanneled" to stereo (pcm 48 kHz).

Is this a bug or am I missing something here?

P.S. I would like to report this as a bug, made an account, but I am afraid that entering of a bug is not possible if you're not 'validated' or something....

If you do a search, there's another thread on this exact topic. It IS already a bug....it was reported many months ago, but the developers for VLC are volunteers, and so far nobody has volunteered to tackle it.

If you do a search, there's another thread on this exact topic. It IS already a bug....it was reported many months ago, but the developers for VLC are volunteers, and so far nobody has volunteered to tackle it.

Thanks for the info. I did a search of course, but could only find this topic on it, and no bug report/ticket.

However, I did a search again and found this topic. I think that is the topic you mean.

VLC is used by so many peaople on so many platforms that I thought it was a (semi)professional developped aplication. Lets hope the volunteers with programming skills tackle this problem some day.

At least it's not my "fault" that I cannot get spdif passthu working. So I'll stop trying until I read in the change-logs that it is fixed (under Linux).

Bye.

Hello, just adding my voice.

Same problem -
Late model KUBUNTU (7.04)
Nforce2 soundsystem (onboard on Gigabyte mobo - it may be old but it works PERFECTLY under Winblows)
SPDI/F out is wired up fine and drives my Boston Acoustics digital speakers.

Analog out works fine.
No SPDI/F out no matter what combos of the switches and sliders in KMix and alsamixer I try.
Briefly took the system to OSS instead of ALSA but no joy there either.

Jon