Browse Prior Art Database

Software Control of Multimedia Audio Output Channels

IP.com Disclosure Number: IPCOM000106756D
Original Publication Date: 1993-Dec-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 147K

Publishing Venue

IBM

Related People

Allran, GG: AUTHOR [+4]

Abstract

Described is a software implementation to provide control of multiple audio output channels as used in multimedia applications. The concept provides a focal point for control of multimedia audio channels through an amp/mixer component wherein audio characteristics, such as volume, balance, treble and bass are controlled on a channel-by-channel basis.

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This is the abbreviated version, containing approximately 44% of the total text.

Software Control of Multimedia Audio Output Channels

      Described is a software implementation to provide control of
multiple audio output channels as used in multimedia applications.
The concept provides a focal point for control of multimedia audio
channels through an amp/mixer component wherein audio
characteristics, such as volume, balance, treble and bass are
controlled on a channel-by-channel basis.

      Typically, during multimedia playback operations, it is
desirable to control the multiple channels.  For example, if music
from a compact disk that is playing in the background has an
interrupt occur due to an audio message, rather than discontinue the
background music it would be preferable to hear both the music and
the message through the use of two mixed audio channels.  This type
of application is possible through the use of two different audio
output adapters playing on different audio channels.  In order to
control the channels, the concept described herein implements
software to allocate and control audio signal channels of amplifier
and mixer devices in a multimedia multi-tasking environment.

      An amp/mixer component is used as the focus for audio signals
being sent to any single audio circuit.  Audio functions, such as
channel volume, master volume, balance, treble, bass and other
equalization functions, are controlled by the amp/mixer component.

For systems to be capable of supporting multiple multimedia
applications, it is important to make effective use of all available
resources.  Ideally, there are no hardware limitations since
multimedia applications can allocate dedicated audio channels.
However, in systems with limited audio output hardware, it is
necessary to allow applications to share and to reuse audio output
channels.

      For example, an audio adapter which is capable of supporting
two channels may in some cases allocate both channels to a single
application pair, left and right.  Alternately, these channels may be
allocated as monaural channels, one each for two applications.  In
another example, it may be desirable to share output channels where
two audio output channels are allocated by an application as serially
reusable.  In this application, the volume level may be set at 50%
left and 50% right.  Another application may request the use of the
same two audio output channels.  An amp/mixer implementation allows
for the saving of volume, balance and other variable settings and
then may allow changes to the settings.  When the application no
longer needs the audio channels, the control is released and the
audio output channel characteristics are reset to previously saved
settings.

      Another important feature of the amp/mixer capability is when
new features are added.  Fig. 1 shows a block diagram of how several
multimedia player applications are communicating with a single
amp/mixer component.  In this case, volume and balance settings are
controlled by applica...