Bug 286914 - Add support for s/pdif or iec958 audio passthrough
Summary: Add support for s/pdif or iec958 audio passthrough
Status: RESOLVED DUPLICATE of bug 171955
Alias: None
Product: Phonon
Classification: Frameworks and Libraries
Component: general (show other bugs)
Version: unspecified
Platform: Ubuntu Linux
: NOR wishlist
Target Milestone: 4.5.2
Assignee: Harald Sitter
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-11-18 11:51 UTC by Thomas Pasch
Modified: 2013-05-25 20:08 UTC (History)
6 users (show)

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Description Thomas Pasch 2011-11-18 11:51:57 UTC
Version:           unspecified (using KDE 4.7.2) 
OS:                Linux

It would be cool if phonon could be configured to pass (dts, ac3, and/or
multichannel PCM) through sdif/toslink/iec958.

In mplayer, this works with this:

> mplayer -ac hwac3,hwdts, -channels 6 -ao alsa:device=iec958 <dts/ac3 file to play>

For GStreamer:

There is a GStreamer plugin for sending AC3 over iec958...
[http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-ugly-plugins/html/gst-plugins-ugly-plugins-plugin-iec958.html]

But the following GStreamer bugs might also be relevant:

[https://bugzilla.gnome.org/show_bug.cgi?id=311423]
[http://gstreamer.freedesktop.org/wiki/PlayBinPassthrough]
I'm not sure if phonon relies on playbin2. But if it does, passthrough could
be difficult to archive.


[https://bugzilla.gnome.org/show_bug.cgi?id=642731]
[https://bugzilla.gnome.org/show_bug.cgi?id=642730]
Both are about passing raw aac through iec958. So it is not exactly what I
asked for... (Well, my amplifier could hardware decode mp3, flac, ogg, and aac.
Hence support for this would be cool as well.)

For VLC:

The VLC GUI provides this feature as well. (Normal preferences: Audio -> 'Dolby Surround', All preferences: Audio -> 'Use s/dif if available').

There is also the KDE Bug 275135 requesting this feature on the (now unmaintained) xine backend. However, is not true any more that GStreamer and/or VLC do not provide this feature.

Reproducible: Always

Steps to Reproduce:
This would be an enhancement. It is not available in phonon today.

Actual Results:  
No way to passthough raw digital data through s/pdif / IEC958. It seems that it is always stripped down to 2-channel PCM.

Expected Results:  
Option to enable passthrough raw digital data through s/pdif / IEC958.
Comment 1 Thomas Pasch 2011-11-20 13:39:08 UTC
BTW, pulseaudio states that passthrough will work with GStreamer (and VLC)
here: [http://www.pulseaudio.org/wiki/Passthrough].
Comment 2 Stefan Burnicki 2012-10-06 16:55:10 UTC
I'm using pulseaudio 1.1, phonon-vlc 0.6, vlc 2.0.3 and passthrough works fine. You just have to open "pavucontrol", select the digital output device in the Configuration tab and check the appropriate checkboxes in the output devices tab. At least with bangarang, which uses the phonon backend, it works just fine. So other applications using phonon should work too.
Comment 3 Jean-Baptiste Kempf 2013-05-25 20:08:54 UTC

*** This bug has been marked as a duplicate of bug 171955 ***