60 lines
1.4 KiB
Text
60 lines
1.4 KiB
Text
.TH AUDIO 3
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.SH NAME
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audio \- audio device
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.SH SYNOPSIS
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.nf
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.B bind -a #A /dev
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.sp 0.3v
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.B /dev/audio
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.B /dev/volume
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.fi
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.SH DESCRIPTION
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The audio device serves a one-level directory,
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giving access to the stereo audio ports.
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.B Audio
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is the data file, which can be written for audio playback.
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Audio data is a sequence of stereo samples, left sample first.
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Each sample is a 16 bit little-endian two's complement integer;
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the default sampling rate is 44.1 kHz.
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.PP
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The length of the
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.B audio
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file as returned by
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.IR stat (2)
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represents the number of bytes buffered for input or output.
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.PP
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.B Volume
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is the control file associated with the audio port.
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Each input and output source has an associated stereo volume control,
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ranging from 0 (quiet) to 100 (loud).
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In addition, there are controls for the sampling rate of the D/A and A/D converters
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latency control and for any tone controls.
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Reads
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return lines of the form
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.IP
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.I source
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.B in left
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.I value
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.B right
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.I value
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.B out left
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.I value
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.B right
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.I value
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.PP
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possibly abbreviated if the values are shared or non-existent.
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For example, if all of the values are shared, the form degenerates to
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.RI ` source
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.IR value '.
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Valid sources depend on the particular audio device,
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though all devices have an
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.B audio
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stereo source, which controls the output volume from the D/A converter
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connected to
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.BR audio .
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.PP
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Writes accept the same format with same abbreviations.
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.SH SOURCE
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.B /sys/src/9/port/devaudio.c
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.SH SEE ALSO
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.IR nusb (4)
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