Technical data

SunOS 5.5 Devices sbpro(7D)
NAME sbpro − Sound Blaster Pro, Sound Blaster 16, and Sound Blaster AWE32 audio device
driver
SYNOPSIS sbpro:sound,sbpro
sbpro:sound,sbproctl
AVAILABILITY x86
DESCRIPTION The Creative Labs Sound Blaster family of audio cards comprises DMA-capable ISA bus
plug-in cards that provide 8 and 16 bit mono and stereo digitized sound recording and
playback over a wide range of sampling rates. Each card includes a digital sound proces-
sor and mixing capability. Some of the cards also support more advanced audio features
such as FM synthesis, advanced signal processing, advanced wave effects, andMIDI capa-
bility; however, the sbpro driver does not currently support those advanced features. The
features and interfaces supported by the Solaris sbpro driver are described here and in
audio(7I).
Some Sound Blaster cards support optional non-audio capabilities such asSCSI interfaces
and CD-ROM interfaces. These interfaces are not supported by the sbpro driver. The
Sound Blaster 16 optionalSCSI-2 interface is supported by the aic(7D) driver.
APPLICATION
PROGRAMMING
INTERFACE
The Sound Blaster device is treated as an exclusive resource: only one process may open
the device at a time. Since the Sound Blaster hardware does not support simultaneous
sound input and output, the sbpro driver does not allow the simultaneous access of the
device by two processes, even if one tries to open it read-only and the other write-only.
The sbpro driver will return"SUNW,sbpro" or "SUNW,sb16" in the name field of the
audio_device structure. The version field will contain the version number of the card’s
DSP chip, and the config field will be set to "SBPRO" or "SB16". The AWE32 is currently
identified as anSB16. In all the discussion below, the Sound BlasterAWE32 behaves the
same as the Sound Blaster 16.
Audio Data Formats The Sound Blaster Pro handles 8-bit samples. In mono mode, audio data may be sam-
pled at rates from 4,000 to 44,100 samples per second. In stereo mode, samples may be
handled at the rates of 11,025 and 22,050 samples per second. The SB-16 can sample 8-bit
or 16-bit mono or stereo data in the range of 5,000 to 44,100 Hz.
The Sound Blaster Pro hardware handles 8 bit linear samples in excess-128 format. The
Sound Blaster 16 handles that format, as well as 16 bit linear samples in two’s comple-
ment format. The sbpro driver will generate and accept data in these formats if
AUDIO_ENCODING_LINEAR is selected in the encoding field of the audio information
structure. 16 bit precision is not available on the Sound Blaster Pro. The sbpro driver
will also accept and generate u−law format data if the encoding field is set to
AUDIO_ENCODING_ULAW. In this case, driver software performs the translation
between linear and u-law formats. u-law encoding is designed to provide an improved
signal-to-noise ratio at low amplitude levels. To achieve best results when using u-law
encoding, the audio record volume should be set so that typical amplitude levels lie
modified 17 Jul 1995 7D-283