audio(3) [plan9 man page]
AUDIO(3) Library Functions Manual AUDIO(3) NAME
audio - digital audio input and output SYNOPSIS
bind -a #A /dev /dev/audio /dev/volume DESCRIPTION
The audio device serves a one-level directory, giving access to the stereo audio ports. Audio is the data file, which can be read or writ- ten to use the port. Audio data is a sequence of stereo samples, left sample first. Each sample is a 16 bit little-endian two's comple- ment integer; the default sampling rate is 44.1 kHz. Some implementations only support audio output and return a zero length when read. Volume is the control file associated with the audio port. Each input and output source has an associated stereo volume control, ranging from 0 (quiet) to 100 (loud). In addition, there are controls for the sampling rate of the D/A and A/D converters and for any tone con- trols. Reads return lines of the form source in left value right value out left value right value possibly abbreviated if the values are shared or non-existent. For example, if all of the values are shared, the form degenerates to `source value'. Valid sources depend on the particular audio device, though all devices have a audio stereo source, which controls the output volume from the D/A converter connected to audio. Writes accept the same format with same abbreviations. Writing the string reset sets all of the attributes to their default value, and if no attribute is supplied, audio is assumed. The Sound Blaster 16 (or MCD) is half-duplex and has the following controls. audio out Data written to audio. synth in out MIDI synthesizer. cd in out CD player. line in out Line-level input. mic in out Monaural microphone input. speaker in out Monaural internal speaker connection. treb out Stereo treble tone control. Values less than 50 decrease the treble, those greater increase it. bass out Stereo bass tone control. speed in out Sampling rate for the D/A and A/D converters, expressed in Hz. Defaults to 44100. Indigo audio is full-duplex and has the following controls. audio out Data written to audio. line in out Line-level input. mic in out Microphone input. aes in out Digital input. Nextstation audio is output only and has the following controls. audio Data written to audio. deemp A value of zero turns off the stereo de-emphasis filter, any other value turns it on. SOURCE
/sys/src/9/*/devaudio.c AUDIO(3)
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mixerctl(1) User Commands mixerctl(1) NAME
mixerctl - audio mixer control command line application SYNOPSIS
/usr/sbin/mixerctl [-a | -d dev] [-iv] [-e | -o] DESCRIPTION
Some audio devices support the audio mixer functionality. See mixer(7I) for a complete description of the audio mixer. The mixerctl command is used to control the mode of the audio mixer and to get information about the audio mixer and the audio device. See audio(7I) for details. OPTIONS
The following options are supported. If none are specified, option -i is assumed: -a The command applies to all audio devices. -d dev The dev argument specifies an alternate audio control device for the command to use. -e Enables the audio mixer function if the audio device supports it. If supported, the audio mixer may be enabled at any time. The command silently ignores the enable option if the audio mixer is already enabled. -i Prints the audio device type information for the device and indicates whether the audio device uses the audio mixer. If the device does use the audio mixer, this option displays the audio mixer's mode. -o Turns off the audio mixer function if the audio device supports it. If supported, the audio mixer may be turned off if only one process has the device opened with the O_RDWR flag, or, if two different processes have the device opened, one with the O_RDONLY flag and the other with the O_WRONLY flag. (See open(2).) The command silently ignores the disable option if the audio mixer function is already disabled. -v Verbose mode. Prints the audio_info_t structure for the device, along with the device type information. This option implies the -i option. ENVIRONMENT VARIABLES
AUDIODEV If the -d and -a options are not specified, the AUDIODEV environment variable is consulted. If set, AUDIODEV will contain the full path name of the user's default audio device. The default audio device will be converted into a control device, and then used. If the AUDIODEV variable is not set, /dev/audioctl is used. FILES
/dev/audioctl /dev/sound/{0...n}ctl ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Architecture |SPARC, x86 | +-----------------------------+-----------------------------+ |Availability |SUNWauda | +-----------------------------+-----------------------------+ |Stability Level |Evolving | +-----------------------------+-----------------------------+ SEE ALSO
audioconvert(1), audioplay(1), audiorecord(1), open(2), attributes(5), usb_ac(7D), audio(7I), audio_support(7I), mixer(7I) SunOS 5.10 12 Mar 2001 mixerctl(1)