[sound-nua] sound preference does not provide ac3 passthrough spdif in 5.1 speaker test

[Joao Silva]

This sound card (Realtek ALC892) is 7.1 channel capable via the digital out (SPDIF).
However, Ubuntu is not recognizing it as such and on the sound configuration we can only see the stereo parameters (right and left).
As you can see in the attached picture, the rear and subwoofer parameters are grayed out, as if the card didn't support it.

I have connected it to a 5.1 amplifier and played a DTS suround file. Unfortunately the sound coming out is simply stereo. No 5.1 surround.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: alsa-base 1.0.25+dfsg-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-25.40-generic 3.2.18
Uname: Linux 3.2.0-25-generic x86_64
NonfreeKernelModules: fglrx
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: jabss 1592 F.... pulseaudio
                      jabss 3738 F.... alsamixer
 /dev/snd/controlC0: jabss 1592 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Generic'/'HD-Audio Generic at 0xfef44000 irq 48'
   Mixer name : 'ATI R6xx HDMI'
   Components : 'HDA:1002aa01,00aa0100,00100200'
   Controls : 6
   Simple ctrls : 1
Card0.Amixer.values:
 Simple mixer control 'IEC958',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Card1.Amixer.info:
 Card hw:1 'Generic_1'/'HD-Audio Generic at 0xfef40000 irq 16'
   Mixer name : 'Realtek ALC892'
   Components : 'HDA:10ec0892,18498892,00100302'
   Controls : 40
   Simple ctrls : 19
Date: Tue Jun 19 00:29:21 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Generic_1 failed
Symptom_Card: Built-in Audio - HD-Audio Generic
Symptom_Jack: Grey SPDIF Out, Rear
Symptom_Type: Only some of outputs are working
Title: [To Be Filled By O.E.M., Realtek ALC892, Grey SPDIF Out, Rear] Playback problem
UpgradeStatus: Upgraded to precise on 2012-04-27 (52 days ago)
dmi.bios.date: 02/09/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.50
dmi.board.name: A75M-ITX
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.50:bd02/09/2012:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnA75M-ITX:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.

[Daniel Letzeisen (dtl131)]

I'm not sure if it will help, but you may want to attach a verbose pulseaudio log: https://wiki.ubuntu.com/PulseAudio/Log

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Raymond (superquad-vortex2)]

Default sample spec: s16le 2ch 44100Hz
Default channel map: front-left,front-right
Default sink name: alsa_output.pci-0000_00_14.2.iec958-stereo
Default source name: alsa_input.pci-0000_00_14.2.analog-stereo

[madbiologist (me-again)]

Does the workaround in bug 778051 help?

[Raymond (superquad-vortex2)]

  device.profile.name = "iec958-stereo"
  device.profile.description = "Digital Stereo (IEC958)"
  device.description = "Built-in Audio Digital Stereo (IEC958)"
  alsa.mixer_name = "Realtek ALC892"
  alsa.components = "HDA:10ec0892,18498892,00100302"
  module-udev-detect.discovered = "1"
  device.icon_name = "audio-card-pci"
 ports:
  iec958-stereo-output: Digital Output (S/PDIF) (priority 0, available: unknown)
   properties:

 active port: <iec958-stereo-output>

[Raymond (superquad-vortex2)]

http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=0b421f0d93f691ccd95d3999a1a9045caee76671

[Joao Silva (joaoabs)]

Reinstaled ubuntu-12.04.3-desktop-amd64 and applied the latest updates. System become:
(Linux cassiopeia 3.8.0-32-generic #47~precise1-Ubuntu SMP Wed Oct 2 16:19:35 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux).

Tried the workaround from bug 778051 and checked the sound properties. Problem persists: The subwoffer and fade controls remain gray and cannot be controlled.

[Raymond (superquad-vortex2)]

you have to switch off "IEC958 Default PCM" if you are using AC3 passthrough

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/?id=9a08160bdbe3148a405f72798f76e2a5d30bd243

[Joao Silva (joaoabs)]

Same result:
The steps I followed:
1) Ran alsamixer from command line and got into screen 1.
2) Choose the second sound card (1) (final behavior is the same if I switch OFF or ON the "HDMI" card (0) ). - Screen2
3) Switched ON the "S/PDIF" column, switched OFF the "S/PDIF Default PCM", by toggling with "M". - Screen 3
4) The Column "PCM" could not be switched OFF. - Screen 3

The audio controls for S/PDIF remain grayed out. I'm not rebooting after doing the changes in alsamixer.

Any idea?

[Raymond (superquad-vortex2)]

[sound-nua] does not provide ac3 passthrough spdif in 5.1 speaker test in sound preference

[Sebastien Bacher (seb128)]

Hey David, do you if that issue is in the settings UI or on the pulseaudio side?

[David Henningsson (diwic)]

About PulseAudio, S/PDIF ac3 output:

PulseAudio does not ship an ac3 encoder by default (I believe it is for patent reasons).
As such there is no way we can output ac3 in speaker test dialog (and we don't ship pre-encoded 5.1 sample wavs either).

As for passthrough support, should be working fairly well in 13.10 (although I have never tested it), but if the input is encoded, there's nothing we can do w r t changing the volumes, as the stream is just passing through in encoded format.

Is this answering your question?

[Sebastien Bacher (seb128)]

Thanks David for the explanation, it seems that the issue is not really in the configuration dialog then...

[Joao Silva (joaoabs)]

Does that mean that this is not a bug after all?

If it does pass-through why don't I get 5.1 sound when playing 5.1 sample files, like this one?

http://www.mysurround.com/test/TestMySurround-en.dbr.ac3

Cheers,
Joaoabs

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 12.04 (precise) reached end-of-life on April 28, 2017.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in.