From SuperTux

Contents 1 About 2 Configuration File 3 Settings 3.1 Format 3.2 Examples 3.3 General 3.4 ALSA Specific 3.5 OSS/DSP Specific 3.6 Irix - DMEDIA 3.7 MacOS/X - Darwin Specific

[edit] About

This is a little writeup about the configuration of the OpenAL SI implementation which is used on Linux, BSD and others (MacOS/X and Windows have their own implementations which are different). Unfortunately there seems to be no documentation about how to configure ALSA yet, so we provide this as an interim solution.

[edit] Configuration File

OpenAL is first trying to read a user settings from an .openalrc in the users home directory if it exists ($HOME/.openalrc). If it can't be found then /etc/openalrc is used. If this also fails the following default settings apply:

(define speaker-num 2)
(define display-banner #t)
(define source-gain 1.0)

This is from the source code, however there seems to be no code to handle display-banner and source-gain...

[edit] Settings

[edit] Format

The settings files are written in LISP (Wikipedia about LISP). Variables get defined with the define command. Example:

(define somevar 5.0)
(define someStringVar "hello")
(define someList '(id1 id2 id3))

[edit] Examples

Normal Linux config, try ALSA and dsp, then fallback to arts and esd or no audio. Stereo sound in CD Quality (44,1khz):

(define devices '(alsa native arts esd null))
(define alsa-device "default")
(define speaker-num 2)
(define sampling-rate 44100)

ALSA surround sound with a 5.1 sound system and 48khz high quality audio:

(define devices '(alsa))
(define speaker-num 6)
(define alsa-out-device "surround51:0,0")
(define alsa-in-device "hw:0,0")
(define sampling-rate 48000)

[edit] General

• devices contains a list of devices which are tried as OpenAL output devices. Possible values are:
  • dsp - OSS (Open Sound System) driver
  • native - Preferred driver for the platform (will load a driver for Darwin, morphos, Solaris, windows, BSD, ALSA or dsp)
  • alsa - ALSA (Advanced Linux Sound System) driver, only available on Linux
  • arts - ARTS, the KDE Sound Daemon
  • dmedia - DMEDIA, seems to be the irix sound api...
  • esd - ESD (Enlightenment Sound Daemon), often found on GNOME installations
  • sdl - SDL (Simple Direct Media Layer), uses the SDL library for sound output
  • null - NULL, no output
  • waveout - Writes to .wav files
• direcion - unclear...
• sampling-rate - The sample rate used for mixing and sound output
• speaker-num - The number of speakers (2 for stereo speakers and headsets, 4,5,6 are supported on alsa for surround sound)
• source-rolloff-factor - default rolloff factor ([1])
• device-params - unclear...

[edit] ALSA Specific

• alsa-device - The alsa device used for sound input and ouput (used when alsa-out-device or alsa-in-device is not defined)
• alsa-out-device - The alsa device used for sound output
• alsa-in-device - The alsa device used for sound input

[edit] OSS/DSP Specific

• lin-dsp-path - Path to the audio device (default /dev/dsp)
• lin-dsp-read-path - Path for audio output device

[edit] Irix - DMEDIA

• dmedia-out-device
• dmedia-in-device
• dmedia-rear-out-device

[edit] MacOS/X - Darwin Specific

• native-backend-debug - set to true for debugging