About the OSS test utility (osstest)
====================================

The osstest applet is a simple test application that can be used to test
functionality of the sound hardware installed in the system. It can be
invoked from soundconf (under some operating system) or being run as an
independent utility (see below).

osstest performs a playback test for each installed audio device. If there
are any "machine detectable" problems they will be reported. A left/right
channel sound file gets played during the test.

It's user's responsibility to listen if the test sound is audible. If no
sound output can be heard the possible reason is one of the following:

0) An error was reported by osstest. In this case there will usually not be
any sound output. The error needs to be fixed before running osstest
again.
1) There is no headphones or speakers connected. Or the connection is not
made correctly.
2) The mixer volume level is set to a too low value (by default it should
be OK). The mixer level can be adjusted using the mixer, ossmix and ossxmix
utilities distributed with OSS.
3) Some notebooks have nonstandard volume control and/or speaker selection
hardware that is not supported by OSS. It's very likely that OSS doesn't
support such vendor specific additions.

If no errors were reported and the test sound was audible it means that
OSS and your sound hardware is functioning correctly. If you still encounter
problems with some sound applications the reason is almost certainly in
the application. Check it's configuration or try to use another equivivalent
application (majority of small freeware applications using OSS are just too
buggy to work). Our application page (http://www.opensound.com/ossapps.html)
contains pointers to applications that are likely to work.

If you are having problems with KDE and/or Gnome system sounds, you need to
make sure that OSS gets started before the GUI environment. The easiest way
to do this is using the "Automatic Boot setup" function of soundconf to make
OSS to be started automatically when the system boots.

Sample rate drift
-----------------

The osstest utility measures a sample rate drift value after playing
back the test sound. Ideally it should be 0% but in practice there
will be an error of few percents. 0% means that the 11025 Hz test file
was played exactly at 11025 Hz sampling rate.

The sample rate measurement is based on the system timer which has limited
precision. It's likely that small (less than 1%) differences between the
nominal and the measured sampling rates are actually caused by an error
in the measurement. For this reason the drift reported by osstest should not
be used as any kind of quality measurement. However if the drift is very
large it means that there is something wrong in the system. The oscillator
chip used with the sound chip is broken or the system clock is running at a
wrong speed.

Using osstest manually
----------------------

The osstest utility is located in the directory where you installed OSS
(usually /usr/lib/oss). It can be run manually to test functionality
of OSS and your sound hardware. When invoked without any command line
parameters osstest performs the default test on all devices. However
it will skip some of the devices base on the following rules.

- Virtual devices (Virtual Mixer) will not be tested. Use the -V
command line option to force test of virtual devices.
- Multiple device files related with the same physical device will not
be tested. Only the first one gets tested while the remaining ones will be
skipped. At this moment there is no way to force osstest to test this kind of
devices.
- Only stereo devices will be tested. Future versions of osstest will be
able to test mono and multi channel devices too. Also osstest requires that
the device supports the 16 bit signed format and 11.025 kHz sampling rate.