Open Sound System
OSS 4.x User's Guide

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oss_usb - USB Audio/MIDI/Mixer driver

The Open Sound System driver for USB Audio and MIDI devices.


The Audio driver supports:


The oss_usb driver supports all MIDI devices that are compatible with the official USB MIDI specification. In addition the driver supports few devices that use their own private protocol (including some Yamaha and Midiman models).


The USB Audio mixer is a new type of mixer that doesn't have
the normal volume controls found on AC97 or Legacy SB devices.
The USB audio mixer provides control for selecting the Alternate
device setting - this usually allows the device to be switched
into a Professional audio mode (eg 24bit or 96Khz mode)


Some USB audio devices use a feature called as alternative settings for
bandwidth management. Typically such devices have multiple high speed
inputs and outputs that may require more bandwidth than provided by the USB
bus. The alternative settings feature is used to select between multiple
low speed devices or just few high speed devices.

When the device has multiple alternative settings an "altsetting" selector
will be visible in the control panel for the device (use ossmix or
ossxmix to change it). Alternative setting OFF means that all
audio devices are disabled. The other settings provide different combinations
of high/medium speed devices. You can use the ossinfo command
(ossinfo -a -v3) to find out the devices supported by the currently selected
alternative settings and the capabilities of them.


Under Linux it is necessary to run the ossdetect -d and ossdevlinks commands
after an USB device has been hot-plugged. Alternatively you can execute
soundoff and soundon to reload OSS.




oss_usb.conf Device configuration file


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