Open Sound System

Related articles
Advanced Linux Sound Architecture#OSS emulation
The
Open Sound System
(OSS) was the original
sound system
for Linux.
It was superseded by the
Advanced Linux Sound Architecture
(ALSA), which has a number of advantages over OSS:
Better support for USB audio devices.
OSS has experimental output support for USB audio devices, but no input.
Support for Bluetooth audio devices.
Support for
AC'97
and
HD Audio
dial-up
softmodems
.
Better support for MIDI devices.
OSS supports MIDI devices with the help of a software synthesizer such as
Timidity
or
FluidSynth
.
Support for suspend.
Better support for jack detection.
Installation
Install
the
oss
AUR
package, or the package with non-free drivers
oss-nonfree
AUR
.
This will install the OSS, run the OSS install script (temporarily disabling the ALSA modules) and install the OSS kernel modules. Since ALSA is enabled by default, you need to disable it so it does not conflict with OSS. You can do this by
blacklisting
the
soundcore
module.
After blacklisting the module, you can
enable
oss.service
to start at boot.
To start using OSS without needing to reboot, check if any ALSA modules are still loaded (ALSA modules start with "snd"):
# lsmod | grep snd
Remove the ALSA modules as follows:
# lsmod | awk ' { print $1 } ' | grep snd | xargs rmmod
Then restart OSS:
# soundoff && soundon
To completely remove ALSA from your system, you can compile a
custom kernel
and disable ALSA in its configuration. See
Gentoo:ALSA#Kernel
for the details.
Note
When uninstalling PulseAudio and ALSA, there is more than one package to remove. Search for "pulse" and "alsa" in your installed packages.
This article or section is out of date.
Reason:
This should be the same as for ALSA, i.e. not recommended by default. See
Advanced_Linux_Sound_Architecture#User_privileges
. (Discuss in
Talk:Open Sound System
)
In case you are not part of the
audio
group, add yourself and
relogin
for the changes to take effect:
# gpasswd -a $USER audio
In case OSS is not able to detect your card when starting it, run:
# ossdetect -v
# soundoff && soundon
Testing
Warning
The default volume is very loud, avoid using earphones and physically lower the volume of your speakers (if possible) before running the test.
Test OSS by running:
$ osstest
You should be able to hear music during the test process. If there is no audio, try to adjust the volume or refer to the
#Troubleshooting
section.
If you want to hear sounds from more than one application simultaneously, you need
vmix
, OSS's software mixer.
Check that vmix is enabled by running:
$ ossmix -a | grep -i vmix
You should see a line like
vmix0-enable ON|OFF (currently ON)
. If you do not see any lines beginning with
vmix
, it probably means that
vmix
has not been attached to your sound device. To attach
vmix
, issue the command:
$ vmixctl attach
device
where
device
is your sound device, e.g.
/dev/oss/oss_envy240/pcm0
.
To avoid having to issue this command manually in the future, you can add it to
/usr/lib/oss/soundon.user
, as suggested by the
official documentation
.
If you get a
"Device or resource busy"
error, you need to add
vmix_no_autoattach=1
to
/usr/lib/oss/conf/osscore.conf
and then reboot.
See which devices are detected by running:
$ ossinfo
You should be able to see your devices listed under
Device Objects
or
Audio Devices
. If the device that you want to use is not at the top of one of these sections, you have to edit
/usr/lib/oss/etc/installed_drivers
and place the driver for your device at the very top. It may be required to restart OSS:
# soundoff && soundon
If this does not work, comment all drivers listed except the ones for your device.
Volume control mixer
To control the volume of various devices, mixers levels will need to be set. There are two mixers:
ossmix
a command-line mixer, similar to the BSD audio mixer
mixerctl
.
ossxmix
a GTK-based graphical mixer.
Color definitions
For high definition (HD) audio,
ossxmix
will color jack configurations by their pre-defined jack colors:
Color
Type
Connector
green
front channels (stereo output)
3.5mm TRS
black
rear channels (stereo output)
3.5mm TRS
grey
side channels (stereo output)
3.5mm TRS
gold
center and subwoofer (dual output)
3.5mm TRS
blue
line level (stereo input)
3.5mm TRS
pink
microphone (mono input)
3.5mm TS
Saving mixer levels
Mixer levels are saved when you shut off your computer.  If you want to save the mixer level immediately, execute as root:
# savemixer
savemixer
can be used to write mixer levels to a file with the
-f
switch and restore by the
-L
switch.
Other mixers
Other mixers that have support for OSS:
Gnome Volume Control
—  for
GNOME
.
https://help.gnome.org/users/gnome-volume-control/stable/
||
gnome
Kmix
— for
KDE
.
https://www.kde.org/applications/multimedia/kmix/
||
kmix
Configuring applications for OSS
Tip
See also
Advanced Linux Sound Architecture#OSS emulation
.
GStreamer-based
If you have problems with applications that use GStreamer for audio, you can try removing
pulseaudio
and installing the
gst-plugins-good
package which is needed by
oss4sink
and
oss4src
.
OpenAL-based
By default OpenAL uses ALSA. To change this, simply define the usage of OSS in
/etc/openal/alsound.conf
:
/etc/openal/alsound.conf
drivers=oss
Audacity
If
Audacity
starts, but it complains that it cannot open the device or simply does not play anything, then you may be using
vmix
which prevents Audacity from having exclusive access to your sound device. To fix this, before running Audacity, run:
$ ossmix vmix0-enable OFF
You can restore
vmix
after closing Audacity with:
$ ossmix vmix0-enable ON
Gajim
By default,
Gajim
uses
aplay -q
to play a sound. For OSS you can change it to the equivalent
ossplay -qq
by going to
Edit > Preferences > Advanced
, opening the
Advanced Configuration Editor
and modifying the
soundplayer
variable accordingly.
MOC
To use
MOC
with OSS v4.1 you must change
OSSMixerDevice
to
/dev/ossmix
in your configuration file (located in
~/.moc
). For issues with the interface try changing the
OSSMixerChannel
by pressing
w
in
mocp
(to change to the sofware mixer).
MPD
MPD
is configured through
/etc/mpd.conf
or
~/.mpdconf
. Check both of these files, looking for something that looks like:
/etc/mpd.conf
...
audio_output {
    type    "alsa"
    name    "Some Device Name"
}
...
If you find an uncommented (the lines do not begin with #'s) ALSA configuration like the one above, comment all of it out, or delete it, and add the following:
/etc/mpd.conf
...
audio_output {
    type    "oss"
    name    "My OSS Device"
}
...
Further configuration might not be necessary for all users. However, if you experience issues (in that MPD does not work properly after it has been restarted), or if you like having specific (i.e. more user-configured, less auto-configured) configuration files, the audio output for OSS can be more specifically configured by finding the card identifier:
$ ossinfo | grep /dev/dsp
Look for the line that says something similar to
/dev/dsp -> /dev/oss/
CARD_IDENTIFIER
/pcm0
. Take note of what your
CARD_IDENTIFIER
is, and add these lines to your OSS
audio_output
in your MPD configuration file:
/etc/mpd.conf
...
audio_output {
    type            "oss"
    name            "My OSS Device"
device          "/dev/oss/<SOME_CARD_IDENTIFIER>/pcm0"
mixer_device    "/dev/oss/<SOME_CARD_IDENTIFIER>/mix0"
}
...
See also:
Music Player Daemon#System-wide configuration
.
MPlayer
If you are using a GUI (SMplayer, GNOME MPlayer, etc.) you can select OSS as the default output in the settings dialogs. If you use
MPlayer
from the command-line, you should specify the sound output:
$ mplayer -ao oss /some/file/to/play.mkv
If you do not want to bother typing it over and over again add
ao=oss
to your configuration file (at
~/.mplayer/config
).
See also:
MPlayer#Configuration
.
VLC media player
You can select OSS as the default output in the audio settings.
Wine
To set OSS support in
Wine
start:
$ winecfg
and go to the
Audio
tab and select the
OSS Driver
.
See also:
Wine#Sound
.
Other applications
If you can not get sound from an application not listed here, try looking at the
Configuring Applications for OSSv4
page.
Search for OSS specific packages with
pacman
or by looking in the
AUR
.
See also:
ossapps
.
Tips and tricks
More convenient and precise volume control
This article or section is a candidate for merging with
#Keyboard volume control
.
Notes:
This partially replaces the existing section without much added value, they can probably be presented as equivalent options in the same section instead of two different ones. (Discuss in
Talk:Open Sound System
)
The volume lever of
ossxmix
is very small, making it difficult to finely control the volume.
Run
ossmix
to find the control you want to control (refer to
ossxmix
), this example is
codec1.jack.green.front
.
Bind the following commands to the
keyboard shortcuts
of the desktop environment.
Increase the volume by 1 (the volume can be between 0 and 100):
$ ossmix codec1.jack.green.front +1
Decrease the volume by 1 (The
--
is needed on some systems so that the
-1
will not be mistaken for a parameter.):
$ ossmix -- codec1.jack.green.front -1
Then you can easily control the volume.
Keyboard volume control
An easy way to mute/unmute and increase/decrease the volume is to use the
ossvol
script.
Download the script and place it at
/usr/bin/ossvol
.
Once you installed it, type:
$ ossvol -t
to toggle mute, or:
$ ossvol -h
to see the available commands.
Note
If
ossvol
gives an error like
Bad mixer control name(987) 'vol'
, you need to edit the script and change the
CHANNEL
variable to your default channel (usually
vmix0-outvol
).
If you want to use multimedia keys with
ossvol
,
map
the following commands to your volume keys:
XF86AudioRaiseVolume
,
XF86AudioLowerVolume
and
XF86AudioMute
:
To mute/unmute the volume:
$ ossvol -t
To lower the volume:
$ ossvol -d 2
To raise the volume:
$ ossvol -i 2
Changing the sample rate
Changing the output sample rate is not obvious at first. Sample rates can only be changed by root and
vmix
must be unused by any programs when a change is requested. Before you follow any of these steps, ensure you are going through a receiver/amplifier and using quality speakers and not simply computer speakers. If you are only using computer speakers, do not bother changing anything here as you will not notice a difference.
By default the sample rate is 48000hz. There are several conditions in which you may want to change this. This all depends on your usage patterns. You want the sample rate you are using to match the media you use the most. If your computer has to change the sampling rate of the media to suit the hardware it is likely, though not guaranteed, that you will have a loss in audio quality. This is most noticeable in down sampling (ie. 96000hz → 48000hz). There is an article about this issue in
Stereophile
which was
discussed
on Apple's
CoreAudio API
mailing list if you wish to learn more about this issue.
This article or section is out of date.
Reason:
Intel HD Audio was released in 2004, most motherboards provide it now. (Discuss in
Talk:Open Sound System
)
Some example sample rates:
44100hz
Sample rate of standard
Red Book
audio CDs.
88000hz
Sample rate of
SACD
high definition audio discs/downloads. It is rare that your motherboard will support this sample rate.
96000hz
Sample rate of most high definition audio downloads. If your motherboard is an
AC'97
motherboard, this is likely to be your highest bitrate.
192000hz
Sample rate of BluRay, and some (very few) high definition downloads. Support for external audio receiver equipment is limited to high end audio. Not all motherboards support this. An example of a motherboard chipset that would support this includes
HD Audio
.
To check what your sample rate is currently set to, run:
$ ossmix | grep rate
You are likely to see
vmix0-rate <decimal value> (currently 48000) (Read-only)
.
This article or section is out of date.
Reason:
The carve-out for Envy24 was probably relevant in 2003, but we're 20 years later… (Discuss in
Talk:Open Sound System
)
If you do not see a
vmix0-rate
(or
vmix1-rate
, etc.) being outputted, then it probably means that
vmix
is disabled. In that case, OSS will use the rate requested by the program which uses the device, so this section does not apply. Exception to this are Envy24 (and Envy24HT) cards that have a special setting
envy24.rate
which has a similar function (see the
oss_envy24
manpage).
To change your sample rate:
First, make sure your card is able to use the new rate. Run
ossinfo -v2
and see if the wanted rate is in the
Native sample rates
output.
As root, run
/usr/lib/oss/scripts/killprocs.sh
. Be aware, this will close any program that currently has an open sound channel.
After all programs occupying
vmix
are terminated, run as root:
vmixctl rate /dev/dsp 96000
replacing the rate with your desired sample rate (and
ossmix envy24.rate 96000
if applicable).
Run
ossmix | grep rate
and check for
vmix0-rate <decimal value> (currently 96000) (Read-only)
to see if you were successful.
To make the changes permanent
add the following to the
soundon.user
file:
/usr/lib/oss/soundon.user
#!/bin/sh

vmixctl rate /dev/dsp 96000
# ossmix envy24.rate 96000 # uncomment if you have an Envy24(HT) card

exit 0
and make it
executable
.
Disable virtual mixing and COOKEDMODE to reduce distortion
vmix
is a virtual mixer audio that mixes multiple audio streams but can reduce the sound quality. Simply unchecking vmix-things in OSS Mixer GUI does not always work.
Turn off
COOKEDMODE
to disable format conversions for all applications and devices.
Edit
the following:
/usr/lib/oss/conf/osscore.conf
cooked_enable=0
vmix_disabled=1
Restart
oss.service
or your computer ifyou encounter errors.
After that you can still control the volume via
ossmix
or
ossxmix
.
Start ossxmix docked to the system tray on startup
KDE
Create an application launcher file named
ossxmix.desktop
in you local application launchers directory (
~/.local/share/applications/
with:
~/.local/share/applications/ossxmix.desktop
[Desktop Entry]
Name=Open Sound System Mixer
GenericName=Audio Mixer
Exec=ossxmix -b
Icon=audio-card
Categories=Application;GTK;AudioVideo;Player;
Terminal=false
Type=Application
Encoding=UTF-8
To have it autostart with your system, add it to the list in
System Settings > System Administration > Startup and Shutdown > Autostart
.
GNOME
As root create a file
/usr/local/bin/ossxmix_bg
with the following content:
/usr/local/bin/ossxmix_bg
#!/bin/sh

exec /usr/bin/ossxmix -b
Then go to
System > Preferences > Start Up Applications
and:
Click
Add
, type
OSSMIX
in the
Name
field and
/usr/local/bin/ossxmix_bg
in
Command
field then click
Add Button
.
Login and logout to see the changes.
Record sound output from a program
See upstream article on
Recording sound output of a program
.
Suspend and hibernation
OSS does not automatically support suspend, it must be manually stopped prior to suspending or hibernating and restarted afterwards.
OSS provides
soundon
and
soundoff
to enable and disable OSS, although they only stop OSS if all processes that use sound are terminated first.
The following script is a rather basic method of automatically unloading OSS prior to suspending and reloading afterwards.
/usr/lib/systemd/system-sleep/50osssound.sh
#!/bin/sh
suspend_osssound()
{
    /usr/lib/oss/scripts/killprocs.sh
    /usr/bin/soundoff
}

resume_osssound()
{
    /usr/bin/soundon
}

case $1 in
    pre)
        suspend_osssound
 	;;
    post)
 	resume_osssound
 	;;
    *) exit $NA
 	;;
esac
Save the contents of this script (as root) into
/usr/lib/systemd/system-sleep/50osssound.sh
and make it
executable
.
Warning
This script is rather basic and will terminate any application directly accessing OSS. Save your work prior to suspending/hibernating.
With this, all your applications should be fine.
Changing the default sound output
When running
osstest
, the first test passes for the first channel, but not for the stereo or right channel, it sounds distorted/hisses.  If this is what your sound is like, then it is set to the wrong output.
*** Scanning sound adapter #-1 ***
/dev/oss/oss_hdaudio0/pcm0 (audio engine 0): HD Audio play front
- Performing audio playback test... 
<left> OK <right> OK <stereo> OK <measured srate 47991.00 Hz (-0.02%)>
The left sounded good, the right and stereo were the distorted ones.
Let the test continue until you get a working output:
/dev/oss/oss_hdaudio0/spdout0 (audio engine 5): HD Audio play spdif-out 
- Performing audio playback test... 
<left> OK <right> OK <stereo> OK <measured srate 47991.00 Hz (-0.02%)>
If this passed the test on all left, right and stereo, proceed to next step.
For the command to change the default output see upstream's
wiki article
. Change it to what works for you, for example:
# ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp_multich
For surround sound (4.0-7.1) choose
dsp_multich
, for only 2 channels,
dsp
is sufficient. See
this
for all available devices.
Settings for a specific driver
If something is not working, there is a possibility that some of your OSS settings are driver specific or just wrong for your driver.
To solve this:
Find out which driver is used
$ lspci -vnnd ::04xx
00:1e.2 Multimedia audio controller [0401]: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio Controller [8086:266e] (rev 03)
Subsystem: Hewlett-Packard Company NX6110/NC6120 [103c:099c]
Flags: bus master, medium devsel, latency 0, IRQ 21
I/O ports at 2100 [size=256]
I/O ports at 2200 [size=64]
Memory at d0581000 (32-bit, non-prefetchable) [size=512]
Memory at d0582000 (32-bit, non-prefetchable) [size=256]
Capabilities: <access denied>
Kernel driver in use: *oss_ich*
Kernel modules: snd-intel8x0
Locate configuration file for device in:
# cd /usr/lib/oss/conf/
Try changing defaults. There are only few settings, and they are self explanatory
For example, the setting:
ich_jacksense = 1
in
oss_ich.conf
turns on
jack-sense
(which is responsible for recognizing plugged headphones and muting the speaker). Other settings for
jack-sense
can be found in
hdaudio.conf
where you have to change the
hdaudio_jacksense
variable.
Restart
the
oss.service
for changes take effects.
Troubleshooting
Troubleshooting HD Audio devices
Understanding the problem
If you have a HD Audio sound device, it is very likely that you will have to adjust some mixer settings before your sound works.
HD Audio devices are very powerful in the sense that they can contain a lot of small circuits (called
widgets
) that can be adjusted by software at any time. These controls are exposed to the mixer, and they can be used, for example, to turn the earphone jack into a sound input jack instead of a sound output jack.
However, there are also bad side effects, mainly because the HD Audio standard is more flexible than it perhaps should be, and because the vendors often only care to get their
official drivers
working.
When using HD Audio devices, you often find disorganized mixer controls, that do not work at all by default, and you are forced to try every mixer control combination possible, until it works.
Solution
Open
ossxmix
and try to change every mixer control in the
middle area
, that contains the sound card specific controls, as explained in the
#Volume control mixer
section.
You will probably want to setup a program to record/play continuously in the background (e.g.
ossrecord - | ossplay -
for recording or
osstest -lV
for playing), while changing mixer settings in
ossxmix
in the foreground.
Raise every volume control slider.
In each option box, try to change the selected option, trying all the possible combinations.
If you get noise, try to lower and/or mute some volume controls, until you find the source of the noise.
Editing
/usr/lib/oss/conf/oss_hdaudio.conf
, uncommenting and changing
hdaudio_noskip=0
to a value from
0-7
can give you more jack options in
ossxmix
.
Note
If you modify this file,
restart
the
oss
daemon for the changes to take effect.
MMS sound cracking in Totem
If you hear various cracks or strange noises in Totem during playback, you can try using another backend such as
FFmpeg
. This will not fix the issue that somehow pops up in GStreamer when playing MMS streams but it will give you the option to play it with good sound quality. Playing it in MPlayer is simple:
# mplayer mmsh://yourstreamurl
Microphone playing through output channels
By default, OSS plays back the microphone through the speakers. To disable this in
ossxmix
find the "Misc" section and uncheck every "input-mix-mute" box.
Add additional HD Audio sound cards support
The factual accuracy of this article or section is disputed.
Reason:
Needs to be adapted to avoid referring to manual compilation : rebuilding
oss
AUR
should be preferred, this section needs to link to the relevant page for customizing an
AUR
package. In particular, the last note is overly generic (dependencies should be handled by the PKGBUILD for example). (Discuss in
Talk:Open Sound System
)
OSS provides a "generic" codec driver that should be able to parse
99% of all HDAudio codecs.
If the device are not listed in the
oss_hdaudio.c
source file, add them to it,
recompile
and start the drivers.
To find the
device/vendor
IDs for "Multimedia controller" device class, do the following:
$ lspci -nnd ::04xx
00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-H HD Audio [
8086:a170
] (rev 31)
In this example, "Vendor ID" is "8086" and "Device ID" is "a170".
Change 5 lines of code in the source code
, taking "
the latest source package
"(currently "oss-v4.2-build2020-src-gpl.tar.bz2") as an example:
oss-v4.2-build2020-src-gpl/devlists/Linux
oss_hdaudio     pci8086,a170    Intel High Definition Audio (PCH_C)
oss-v4.2-build2020-src-gpl/kernel/drv/oss_hdaudio/.devices
oss_hdaudio     pci8086,a170    Intel High Definition Audio (PCH_C)
oss-v4.2-build2020-src-gpl/kernel/drv/oss_hdaudio/oss_hdaudio.c
#define INTEL_DEVICE_PCH_C      0xa170
    case INTEL_DEVICE_PCH_C:		#Don't add it, it's already there
It is better to modify the existing "Controller" (
"PCH_C"
in this example), appending a new line of code may fail. It does not matter if it is
PCH_C
.
The last line of code is a bit complicated. This example is an ALC1150 sound card chip. The "Vendor_id" of "ALC1150" is "0x10ec0900", you can get it through a search engine, or try the following:
# cat /sys/class/sound/card0/device/hdaudioC0D0/vendor_id
0x10ec0900
# cat /sys/class/sound/card0/device/sound/card0/hwC0D0/vendor_id
0x10ec0900
For sound card chips of different manufacturers, different paragraphs need to be modified. In the example, the paragraph of Realtek manufacturer:
oss-v4.2-build2020-src-gpl/kernel/drv/oss_hdaudio/hdaudio_codecids.h
{0x10ec0889, "ALC889", VF_ALC88X_HACK, (char **) &alc883remap}, 
  {0x10ec0900, "ALC1150", VF_ALC88X_HACK, (char **) &alc883remap}, 
  {0x10ec0899, "ALC899", VF_ALC88X_HACK, (char **) &alc883remap},
It is very important that on the hardware of this example, modifying the second-to-last line works, but modifying the same code on the first-to-last line fails. You will need to try and modify the same code over and over on different lines to work on your hardware.
For example, try on the 4th last line:
{0x10ec0887, "ALC887", VF_ALC88X_HACK, (char **) &alc883remap}, 
 {0x10ec0900, "ALC1150", VF_ALC88X_HACK, (char **) &alc883remap}, 
 {0x10ec0889, "ALC889", VF_ALC88X_HACK, (char **) &alc883remap}, 
 {0x10ec0892, "ALC892", VF_ALC88X_HACK, (char **) &alc883remap}, 
 {0x10ec0899, "ALC899", VF_ALC88X_HACK, (char **) &alc883remap},
Note
Dependency packages required for compiling OSS do not need to be installed one by one, the
base-devel
meta package
provides the tools for
creating packages
.
You also need to install the toolkit for
building kernel modules
, which are built during the install phase.
See also
Official Website
OSS Wiki
OSS Forum
Developer Information
Git repository
opensound-devel mailing list