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• Launchpad entry: none yet

• Packages affected: gnome-control-center

Summary

Make it easy for users to configure their sound output setup (5.1 surround, 4.0 speakers, 2.0 speakers, etc.)

Rationale

Currently, you have to edit several configuration files to make programs output on all your surround channels. This confuses people, who are used to have a simple way to switch between 'headphones' (2.0) and full surround (4.0, 5.1 or 7.1).

Use cases

• Martijn buys a new 5.1 surround speaker set, to experience the sound of his DVDs better. He connects them to the colored connectors on the back of his PC, selects '5.1' from in the Sound Preferences panel, and all programs (including games) start using surround sound.
• Matias has a 5.1 surround set, but his neighbors complained. So he plugs in his headphones, selects 'Headphones' in the Sound Preferences panel, and suddenly all programs use only stereo sound.

Scope

This specification covers the Sound Preferences panel, and maybe bits of ALSA.

Design

A detection script or program is needed to only offer the capabilities that are actually available, it should probably be built based on speaker-test (an alsa tool) or its code.

Implementation

tbd

Code

Data preservation and migration

n/a

Unresolved issues

• Can we ask ALSA for a list of supported configurations? Some sound cards only support stereo output, others only stereo or 5.1, others even 7.1. It would be nice to show only the options that will really work on the selected sound card.
• Maybe add an option for 'digital' (IEC958; 'S/PDIF') too?
• We might need to set the volume levels and mute flags on the surround/center mixer devices to proper levels before it all works.
• What do we want to configure? Just alsa/gstreamer? Or also OpenAL? Other sound libraries?
• Regarding the previous question, most applications may require restarting before this setting taking effect, all libraries and programs that do not require restarting should probably be configured. The others are a tougher choice (DBUS may offer a solution?).
• There is already an option like this in the Totem Preferences screen. Check how that works, move it out (and into the sound panel) and add configuring other libraries?
• gconf-keys used by the current control-center thingy in /system/gstreamer/0.10/default ; totem key is /apps/totem/audio_output_type

BoF agenda and discussion

CategorySpec