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Annotation of lucent/sys/man/3/audio, revision 1.1.1.1

1.1       root        1: .TH AUDIO 3 
                      2: .SH NAME
                      3: audio \- digital audio input and output
                      4: .SH SYNOPSIS
                      5: .nf
                      6: .B bind -a #A /dev
                      7: 
                      8: .B /dev/audio
                      9: .B /dev/volume
                     10: .fi
                     11: .SH DESCRIPTION
                     12: .PP
                     13: The audio device serves a one-level directory,
                     14: giving access to the stereo audio ports.
                     15: .B Audio
                     16: is the data file, which can be read or written to use the port.
                     17: Audio data is a sequence of stereo samples, left sample first.
                     18: Each sample is a 16 bit little-endian two's complement integer;
                     19: the default sampling rate is 44.1 kHz.
                     20: Some implementations only support audio output
                     21: and return a zero length when read.
                     22: .PP
                     23: .B Volume
                     24: is the control file associated with the audio port.
                     25: Each input and output source has an associated stereo volume control,
                     26: ranging from 0 (quiet) to 100 (loud).
                     27: In addition, there are controls for the sampling rate of the D/A and A/D converters
                     28: and for any tone controls.
                     29: Reads
                     30: return lines of the form
                     31: .IP
                     32: .I source
                     33: .B in\ left
                     34: .I value 
                     35: .B right
                     36: .I value
                     37: .B out\ left
                     38: .I value
                     39: .B right
                     40: .I value
                     41: .PP
                     42: possibly abbreviated if the values are shared or non-existent.
                     43: For example, if all of the values are shared, the form degenerates to
                     44: .RI ` source
                     45: .IR value '.
                     46: Valid sources depend on the particular audio device,
                     47: though all devices have a
                     48: .B audio
                     49: stereo source, which controls the output volume from the D/A converter
                     50: connected to
                     51: .BR audio .
                     52: .PP
                     53: Writes accept the same format with same abbreviations.
                     54: Writing the string
                     55: .B reset
                     56: sets all of the attributes to their default value,
                     57: and if no attribute is supplied,
                     58: .B audio
                     59: is assumed.
                     60: .PP
                     61: The Sound Blaster 16 (or MCD) is half-duplex and has the following controls.
                     62: .TP
                     63: .B audio out
                     64: Data written to audio.
                     65: .TP
                     66: .B synth in out
                     67: MIDI synthesizer.
                     68: .TP
                     69: .B cd in out
                     70: CD player.
                     71: .TP
                     72: .B line in out
                     73: Line-level input.
                     74: .TP
                     75: .B mic in out
                     76: Monaural microphone input.
                     77: .TP
                     78: .B speaker in out
                     79: Monaural internal speaker connection.
                     80: .TP
                     81: .B treb out
                     82: Stereo treble tone control.
                     83: Values less than 50 decrease the treble,
                     84: those greater increase it.
                     85: .TP
                     86: .B bass out
                     87: Stereo bass tone control.
                     88: .TP
                     89: .B speed in out
                     90: Sampling rate for the D/A and A/D converters,
                     91: expressed in Hz.
                     92: Defaults to 44100.
                     93: .PP
                     94: Indigo audio is full-duplex and has the following controls.
                     95: .TP
                     96: .B audio out
                     97: Data written to audio.
                     98: .TP
                     99: .B line in out
                    100: Line-level input.
                    101: .TP
                    102: .B mic in out
                    103: Microphone input.
                    104: .TP
                    105: .B aes in out
                    106: Digital input.
                    107: .PP
                    108: Nextstation audio is output only and has the following controls.
                    109: .TP
                    110: .B audio
                    111: Data written to audio.
                    112: .TP
                    113: .B deemp
                    114: A
                    115: .I value
                    116: of zero turns off the stereo de-emphasis filter,
                    117: any other value turns it on.
                    118: .SH SOURCE
                    119: .B /sys/src/9/*/devaudio.c

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