Annotation of src/usr.bin/aucat/aucat.1, Revision 1.69
1.69 ! ratchov 1: .\" $OpenBSD: aucat.1,v 1.68 2010/04/21 06:13:07 ratchov Exp $
1.1 kstailey 2: .\"
1.16 ratchov 3: .\" Copyright (c) 2006 Alexandre Ratchov <alex@caoua.org>
1.1 kstailey 4: .\"
1.16 ratchov 5: .\" Permission to use, copy, modify, and distribute this software for any
6: .\" purpose with or without fee is hereby granted, provided that the above
7: .\" copyright notice and this permission notice appear in all copies.
1.1 kstailey 8: .\"
1.16 ratchov 9: .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
1.1 kstailey 16: .\"
1.69 ! ratchov 17: .Dd $Mdocdate: April 21 2010 $
1.1 kstailey 18: .Dt AUCAT 1
1.5 aaron 19: .Os
1.1 kstailey 20: .Sh NAME
21: .Nm aucat
1.47 ratchov 22: .Nd audio server and stream manipulation tool
1.1 kstailey 23: .Sh SYNOPSIS
24: .Nm aucat
1.16 ratchov 25: .Bk -words
1.59 ratchov 26: .Op Fl dlnu
1.49 jmc 27: .Op Fl b Ar nframes
1.16 ratchov 28: .Op Fl C Ar min : Ns Ar max
29: .Op Fl c Ar min : Ns Ar max
30: .Op Fl e Ar enc
1.9 millert 31: .Op Fl f Ar device
1.16 ratchov 32: .Op Fl h Ar fmt
33: .Op Fl i Ar file
1.68 ratchov 34: .Op Fl j Ar flag
1.37 ratchov 35: .Op Fl m Ar mode
1.16 ratchov 36: .Op Fl o Ar file
1.66 ratchov 37: .Op Fl q Ar device
1.16 ratchov 38: .Op Fl r Ar rate
1.57 ratchov 39: .Op Fl s Ar name
1.62 ratchov 40: .Op Fl t Ar mode
1.54 ratchov 41: .Op Fl U Ar unit
1.30 ratchov 42: .Op Fl v Ar volume
1.22 ratchov 43: .Op Fl x Ar policy
1.62 ratchov 44: .Op Fl z Ar nframes
1.16 ratchov 45: .Ek
1.1 kstailey 46: .Sh DESCRIPTION
47: The
1.7 aaron 48: .Nm
1.16 ratchov 49: utility can record one input stream
50: and store it on multiple destination files,
51: doing the necessary conversions on the fly.
1.48 ratchov 52: It can play, convert, and mix multiple input files simultaneously,
53: and can also act as an audio server.
1.9 millert 54: .Nm
1.16 ratchov 55: also has a legacy mode that works like previous versions of
56: .Nm ,
57: which does not convert on the fly and supports playback of .au files.
1.17 jmc 58: .Pp
1.16 ratchov 59: The options are as follows:
1.26 ratchov 60: .Bl -tag -width Ds
1.49 jmc 61: .It Fl b Ar nframes
1.66 ratchov 62: The buffer size of the audio device in frames.
1.49 jmc 63: A frame consists of one sample for each channel in the stream.
64: This is the number of frames that will be buffered before being played
65: and thus controls the playback latency.
1.25 jmc 66: .It Xo
67: .Fl C Ar min : Ns Ar max ,
68: .Fl c Ar min : Ns Ar max
69: .Xc
1.26 ratchov 70: The range of channel numbers on the record or playback stream, respectively.
1.17 jmc 71: The default is 0:1, i.e. stereo.
1.59 ratchov 72: .It Fl d
73: Do not daemonize.
74: If this option is specified,
75: .Nm
76: will run in the foreground and log to
77: .Em stderr .
1.26 ratchov 78: .It Fl e Ar enc
79: Encoding of the playback or recording stream (see below).
1.17 jmc 80: The default is signed, 16-bit, native byte order.
81: .It Fl f Ar device
82: The
1.57 ratchov 83: .Xr sndio 7
84: audio device to use for playing and/or recording.
1.26 ratchov 85: .It Fl h Ar fmt
86: File format of the playback or record stream (see below).
1.17 jmc 87: The default is auto.
1.16 ratchov 88: .It Fl i Ar file
89: Add this file to the list of files to play.
90: If the option argument is
91: .Sq -
92: then standard input will be used.
1.68 ratchov 93: .It Fl j Ar flag
94: Control whether channels are joined or expanded if
95: the stream number of channels is not equal to the device number of channels.
96: If the flag is
97: .Va off
98: then stream channels are routed to the corresponding
99: device channel, possibly discarding channels not present in the device.
100: If the flag is
101: .Va on ,
102: then a single stream channel may be sent on multiple device channels,
103: or multiple stream channels may be sent to a single device channel.
104: For instance, this feature could be used to request mono streams to
105: be sent on multiple outputs or to record a stereo input into a mono stream.
106: The default is
107: .Ar on .
1.26 ratchov 108: .It Fl l
1.60 sobrado 109: Listen for incoming connections on a
1.61 sobrado 110: .Ux Ns -domain
111: socket.
1.39 jmc 112: This allows clients to use
1.26 ratchov 113: .Nm
1.57 ratchov 114: instead of the physical audio device for audio input and output
1.26 ratchov 115: in order to share the physical device with other clients.
1.57 ratchov 116: The default
117: .Xr sndio 7
118: device exposed is
119: .Pa aucat:0
120: .Pq "also known as" Pa aucat:0.default
1.45 ratchov 121: but other names can be used with the
1.35 ratchov 122: .Fl s
123: option.
1.37 ratchov 124: .It Fl m Ar mode
1.66 ratchov 125: Set the stream mode.
1.37 ratchov 126: Valid modes are
1.39 jmc 127: .Ar play ,
128: .Ar rec ,
1.37 ratchov 129: and
1.66 ratchov 130: .Ar mon ,
131: corresponding to playback, recording and monitoring.
132: A monitoring stream is a fake recording stream corresponding to
133: the mix of all playback streams.
134: Multiple modes can be specified, separated by commas,
135: but the same stream cannot be used for both recording and monitoring.
1.37 ratchov 136: The default is
1.67 jmc 137: .Ar play , Ns Ar rec
1.66 ratchov 138: (i.e. full-duplex).
1.42 ratchov 139: .It Fl n
140: Loopback mode.
141: Instead of using an audio device, send input streams
142: to the output, processing them on the fly.
143: This mode is useful to mix, demultiplex, resample or reencode
1.43 jmc 144: audio files offline.
1.16 ratchov 145: .It Fl o Ar file
146: Add this file to the list of files in which to store recorded samples.
147: If the option argument is
148: .Sq -
149: then standard output will be used.
1.66 ratchov 150: .It Fl q Ar device
151: The
152: .Xr sndio 7
153: MIDI device to use for controlling stream volumes or
154: to start multiple streams synchronously.
1.26 ratchov 155: .It Fl r Ar rate
156: Sample rate in Hertz of the playback or record stream.
1.17 jmc 157: The default is 44100Hz.
1.57 ratchov 158: .It Fl s Ar name
159: Add
160: .Ar name
161: to the list of sub-devices to expose in server mode.
162: Defining multiple sub-devices allows splitting a physical audio device
1.63 jmc 163: into logical devices having different properties (e.g. channel ranges).
1.57 ratchov 164: The given
165: .Ar name
1.62 ratchov 166: corresponds to the
1.57 ratchov 167: .Dq option
168: part of the
169: .Xr sndio 7
170: device name string.
1.62 ratchov 171: .It Fl t Ar mode
1.67 jmc 172: Select the way sub-devices are controlled by MIDI Machine Control (MMC)
173: messages.
1.62 ratchov 174: If the mode is
175: .Va off
176: (the default), then streams are not affected by MMC messages.
177: If the mode is
178: .Va slave ,
179: then streams are started synchronously by MMC start messages;
1.67 jmc 180: additionally, the server clock is exposed as MIDI Time Code (MTC)
1.62 ratchov 181: messages allowing MTC-capable software or hardware to be synchronized
182: to audio streams.
1.54 ratchov 183: .It Fl U Ar unit
184: Unit number to use when running in server mode.
185: Each
186: .Nm
187: server instance has an unique unit number,
188: used in
189: .Xr sndio 7
190: device names.
191: The default is 0.
1.16 ratchov 192: .It Fl u
1.21 jmc 193: Normally
194: .Nm
195: tries to automatically determine the optimal parameters for the audio device;
196: if this option is specified,
197: it will instead use the parameters specified by the
1.26 ratchov 198: .Fl Ccer
1.21 jmc 199: options.
1.30 ratchov 200: .It Fl v Ar volume
201: Software volume attenuation of the playback stream.
202: The value must be between 1 and 127,
1.31 jmc 203: corresponding to \-42dB and \-0dB attenuation.
1.33 ratchov 204: In server mode, clients inherit this parameter.
1.34 jmc 205: Reducing the volume in advance reduces a client's dynamic range,
206: but allows client volume to stay independent from the number
1.33 ratchov 207: of clients as long as their number is small enough.
1.34 jmc 208: A good compromise is to use \-4dB attenuation (12 volume units)
209: for each additional client expected
210: (115 if 2 clients are expected, 103 for 3 clients, and so on).
1.26 ratchov 211: .It Fl x Ar policy
1.22 ratchov 212: Action when the output stream cannot accept
1.26 ratchov 213: recorded data fast enough or the input stream
214: cannot provide data to play fast enough.
1.22 ratchov 215: If the policy
216: is
1.23 jmc 217: .Dq ignore
1.26 ratchov 218: (the default) then samples that cannot be written are discarded
219: and samples that cannot be read are replaced by silence.
1.22 ratchov 220: If the policy is
1.23 jmc 221: .Dq sync
1.26 ratchov 222: then recorded samples are discarded, but the same amount of silence will be written
1.22 ratchov 223: once the stream is unblocked, in order to reach the right position in time.
1.26 ratchov 224: Similarly silence is played, but the same amount of samples will be discarded
225: once the stream is unblocked.
1.22 ratchov 226: If the policy is
1.23 jmc 227: .Dq error
228: then the stream is closed permanently.
1.62 ratchov 229: .Pp
1.67 jmc 230: If a sub-device is created with the
231: .Fl t
232: option,
1.63 jmc 233: the
1.62 ratchov 234: .Dq ignore
1.63 jmc 235: action is disabled for any stream connected to it
236: to ensure proper synchronization.
1.62 ratchov 237: .It Fl z Ar nframes
238: The audio block size in frames.
1.63 jmc 239: This is the number of frames between audio clock ticks,
240: i.e. the clock resolution.
1.67 jmc 241: If a sub-device is created with the
242: .Fl t
243: option,
244: and MTC is used for synchronization, the clock
1.62 ratchov 245: resolution must be 96, 100 or 120 ticks per second for maximum
1.63 jmc 246: accuracy.
247: For instance, 120 ticks per second at 48000Hz corresponds
248: to a 400 frame block size.
1.21 jmc 249: .El
250: .Pp
1.32 ratchov 251: If
252: .Nm
253: is sent
1.44 ratchov 254: .Dv SIGHUP ,
255: .Dv SIGINT
256: or
257: .Dv SIGTERM ,
1.32 ratchov 258: it terminates recording to files.
259: .Pp
1.35 ratchov 260: Settings for input files
261: .Pq Fl i ,
262: output files
1.39 jmc 263: .Pq Fl o ,
1.57 ratchov 264: and sub-devices
1.35 ratchov 265: .Pq Fl s
266: can be changed using the
267: .Fl Ccehrvx
1.16 ratchov 268: options.
1.21 jmc 269: The last
1.35 ratchov 270: .Fl Ccehrvx
1.23 jmc 271: options specified before an
1.35 ratchov 272: .Fl i ,
1.39 jmc 273: .Fl o ,
274: or
1.35 ratchov 275: .Fl s
1.41 jmc 276: are applied to the corresponding file.
1.21 jmc 277: .Pp
278: Settings for the audio device
279: can be changed using the
1.26 ratchov 280: .Fl Ccer
1.21 jmc 281: options.
282: They apply to the audio device only if the
283: .Fl u
284: option is given as well.
285: The last
1.26 ratchov 286: .Fl Ccer
1.21 jmc 287: option specified before an
1.16 ratchov 288: .Fl f
1.21 jmc 289: is applied to
290: .Ar device .
291: .Pp
292: If no audio device
293: .Pq Fl f
1.53 ratchov 294: is specified,
295: settings are applied as if
296: the default device is specified as the last argument.
1.57 ratchov 297: If no sub-devices
1.53 ratchov 298: .Pq Fl s
299: are specified
300: settings are applied as if
1.57 ratchov 301: .Ar default
302: is specified as the last argument.
1.14 jmc 303: .Pp
1.20 jmc 304: File formats are specified using the
305: .Fl h
1.26 ratchov 306: option.
1.16 ratchov 307: The following file formats are supported:
1.66 ratchov 308: .Bl -tag -width s32lexxx -offset indent
1.16 ratchov 309: .It raw
310: Headerless file.
1.17 jmc 311: This format is recommended since it has no limitations.
1.16 ratchov 312: .It wav
313: Microsoft WAVE file format.
314: There are limitations inherent to the file format itself:
315: not all encodings are supported,
316: file sizes are limited to 2GB,
1.17 jmc 317: and the file must support the
1.16 ratchov 318: .Xr lseek 2
1.17 jmc 319: operation (e.g. pipes do not support it).
1.16 ratchov 320: .It auto
321: Try to guess, depending on the file name.
1.9 millert 322: .El
323: .Pp
1.20 jmc 324: Encodings are specified using the
325: .Fl e
1.26 ratchov 326: option.
1.16 ratchov 327: The following encodings are supported:
328: .Pp
1.66 ratchov 329: .Bl -tag -width s32lexxx -offset indent -compact
1.16 ratchov 330: .It s8
331: signed 8-bit
332: .It u8
333: unsigned 8-bit
334: .It s16le
335: signed 16-bit, little endian
336: .It u16le
337: unsigned 16-bit, little endian
338: .It s16be
339: signed 16-bit, big endian
340: .It u16be
341: unsigned 16-bit, big endian
342: .It s24le
343: signed 24-bit, stored in 4 bytes, little endian
344: .It u24le
345: unsigned 24-bit, stored in 4 bytes, little endian
346: .It s24be
347: signed 24-bit, stored in 4 bytes, big endian
348: .It u24be
349: unsigned 24-bit, stored in 4 bytes, big endian
350: .It s32le
351: signed 32-bit, little endian
352: .It u32le
353: unsigned 32-bit, little endian
354: .It s32be
355: signed 32-bit, big endian
356: .It u32be
357: unsigned 32-bit, big endian
358: .It s24le3
359: signed 24-bit, packed in 3 bytes, little endian
360: .It u24le3
361: unsigned 24-bit, packed in 3 bytes, big endian
362: .It s24be3
363: signed 24-bit, packed in 3 bytes, little endian
364: .It u24be3
365: unsigned 24-bit, packed in 3 bytes, big endian
366: .It s20le3
367: signed 20-bit, packed in 3 bytes, little endian
368: .It u20le3
369: unsigned 20-bit, packed in 3 bytes, big endian
370: .It s20be3
371: signed 20-bit, packed in 3 bytes, little endian
372: .It u20be3
373: unsigned 20-bit, packed in 3 bytes, big endian
374: .It s18le3
375: signed 18-bit, packed in 3 bytes, little endian
376: .It u18le3
377: unsigned 18-bit, packed in 3 bytes, big endian
378: .It s18be3
379: signed 18-bit, packed in 3 bytes, little endian
380: .It u18be3
381: unsigned 18-bit, packed in 3 bytes, big endian
382: .El
1.46 ratchov 383: .Sh SERVER MODE
384: .Nm
385: can be used in server mode
386: .Pq Fl l
387: to overcome hardware limitations and allow applications
388: to run on fixed sample rate devices or on devices
389: supporting only unusual encodings.
1.69 ! ratchov 390: .Pp
! 391: The
! 392: .Nm
! 393: audio server may be started by the super-user,
! 394: in which case any user will be able to connect to it.
! 395: For privacy reasons, only one user may have connections to it
! 396: at a given time.
! 397: .Pp
! 398: Alternatively, each user may run his instance
! 399: of the server.
1.46 ratchov 400: It is generally not desirable to have multiple
401: instances of
402: .Nm
403: running in server mode,
404: so it is good practice to start it thus:
405: .Bd -literal -offset indent
406: $ pgrep -x aucat || aucat -l
407: .Ed
408: .Pp
409: This also ensures privacy by preventing
410: other users from accessing the audio system.
411: On multi-user machines
412: .Nm
413: should be killed when no longer in use to make audio resources
414: available again to others:
415: .Bd -literal -offset indent
416: $ pkill -x aucat
417: .Ed
418: .Pp
419: Certain applications, such as synthesis software,
420: require a low latency audio setup.
421: To reduce the probability of buffer underruns or overruns,
422: the
423: .Xr renice 8
1.49 jmc 424: command can be used to give a higher priority to the
1.46 ratchov 425: .Nm
1.49 jmc 426: process.
1.46 ratchov 427: Superuser privileges are required.
428: For example:
429: .Bd -literal -offset indent
430: $ aucat -b 3500 -l
431: $ sudo renice -n -20 -p `pgrep -x aucat`
432: .Ed
1.55 ratchov 433: .Sh MIDI CONTROL
434: While running in server mode
435: .Pq Fl l
436: .Nm
437: exposes a MIDI device with the same name as the default audio
438: device.
1.62 ratchov 439: It allows MIDI hardware or software to control programs
440: using
441: .Nm
442: or to synchronize to them.
443: .Pp
1.56 jmc 444: A MIDI channel is assigned to each stream, and the volume
1.55 ratchov 445: is changed using the standard volume controller (number 7).
446: Similarly, when the audio application changes its volume,
447: the same MIDI controller message is sent out; it can be used
1.56 jmc 448: for instance for monitoring or as feedback for motorized
1.55 ratchov 449: faders.
1.62 ratchov 450: .Pp
1.67 jmc 451: Clients connected to sub-devices created with the
1.63 jmc 452: .Fl t
1.67 jmc 453: option are controlled by the following MMC messages:
1.66 ratchov 454: .Bl -tag -width relocateXXX -offset indent
1.62 ratchov 455: .It relocate
456: Gives
457: .Nm
458: the time, relative to the beginning of the stream, at which playback
459: and recording must start.
460: It is not interpreted by
461: .Nm
462: itself.
1.63 jmc 463: The given time position is sent to MIDI clients as an MTC
1.62 ratchov 464: .Dq "full frame"
465: message forcing all MTC-slaves to relocate to the given
466: position (see below).
467: .It start
468: Put the sub-device in starting mode.
469: In this mode, the sub-device waits for all streams to become ready
470: to start, and then starts them synchronously.
471: Once started, new streams can be created, but they will be blocked
472: until the next stop-to-start transition.
1.67 jmc 473: .It stop
474: Put the sub-device in stopped mode (the default).
475: In this mode, any stream attempting to start playback or recording
476: is paused.
477: Streams that are already started are not affected until they stop
478: and try to start again.
1.62 ratchov 479: .El
480: .Pp
1.67 jmc 481: Sub-devices created with the
1.63 jmc 482: .Fl t
1.67 jmc 483: option export the server clock using MTC, allowing non-audio
1.62 ratchov 484: software or hardware to be synchronized to the audio stream.
485: The following sample rates
486: .Pq Fl r
487: and block sizes
488: .Pq Fl z
489: are recommended for maximum accuracy:
490: .Pp
1.66 ratchov 491: .Bl -bullet -offset indent -compact
1.62 ratchov 492: .It
493: 44100Hz, 441 frames
494: .It
495: 48000Hz, 400 frames
496: .It
497: 48000Hz, 480 frames
498: .It
499: 48000Hz, 500 frames
500: .El
501: .Pp
502: For instance, the following command will create two devices:
503: the default
504: .Va aucat:0
1.63 jmc 505: and a MIDI-controlled
506: .Va aucat:0.mmc :
1.62 ratchov 507: .Bd -literal -offset indent
508: $ aucat -l -r 48000 -z 400 -s default -t slave -s mmc
509: .Ed
510: .Pp
511: Streams connected to
512: .Va aucat:0
513: behave normally, while streams connected to
514: .Va aucat:0.mmc
515: wait for the MMC start signal and start synchronously.
1.63 jmc 516: Regardless of which device a stream is connected to,
517: its playback volume knob is exposed.
1.66 ratchov 518: .Pp
519: If
520: .Nm
521: is used to play and record audio files, it offers
522: similar MIDI control.
523: .Nm
524: can open a
525: .Xr sndio 7
526: MIDI device allowing MIDI hardware or software
527: to control playback and recording in real time.
528: .Pp
529: A MIDI channel is assigned to each stream, and the volume
530: is changed using the standard volume controller (number 7).
1.67 jmc 531: Streams created with the
1.66 ratchov 532: .Fl t
1.67 jmc 533: option are controlled by the following MMC messages:
1.66 ratchov 534: .Bl -tag -width relocateXXX -offset indent
1.67 jmc 535: .It relocate
536: Streams are relocated to the requested time postion
537: relative to the beginning of the stream, at which playback
538: and recording must start.
539: If the requested position is beyond the end of file,
540: the stream is temporarly disabled until a valid postion is requested.
1.66 ratchov 541: .It start
542: Start all streams synchronously.
543: By default, streams are created in a stopped state.
544: .It stop
545: Playback or recording is stopped, and
546: the stream is rewound back to the starting position.
547: .El
548: .Pp
549: For instance, the following command will play a file on the
550: .Va aucat:0.mmc
551: audio device, and give full control to MIDI software or hardware
552: connected to the
553: .Va midithru:0
554: MIDI device:
555: .Bd -literal -offset indent
556: $ aucat -f aucat:0.mmc -t slave -q midithru:0 -i file.wav
557: .Ed
558: .Pp
559: At this stage,
560: .Nm
561: will start, stop and relocate automatically following all user
562: actions in the MIDI sequencer.
563: Note that the sequencer must use
564: .Va aucat:0
565: as the MTC source, i.e. the audio server, not the audio player.
1.16 ratchov 566: .Sh LEGACY MODE
567: If neither
568: .Fl i
569: nor
570: .Fl o
1.17 jmc 571: are specified,
1.16 ratchov 572: .Nm
1.17 jmc 573: will run in legacy mode, and won't convert sample formats or sampling rates.
1.16 ratchov 574: In legacy mode, all options except
1.17 jmc 575: .Fl f
576: are ignored, and all other arguments are assumed to be names of files.
1.16 ratchov 577: In legacy mode
578: .Nm
579: reads files sequentially, and writes them to the specified device.
580: If a Sun .au header is detected it is skipped over and not copied to
581: the audio device.
582: .Nm
1.52 jakemsr 583: will attempt to parse the format, number of channels and sample rate
584: from Sun .au file headers.
585: However, only alaw and ulaw formats are supported for .au files.
586: Other formats will be interpreted as ulaw.
1.16 ratchov 587: If a Microsoft .wav header (RIFF) is detected it is interpreted
588: to select the right audio encoding for playback and the data chunk of the
589: file is copied to the audio device.
590: If the device does not support the encoding,
591: .Nm
592: will exit with an error.
1.9 millert 593: .Sh ENVIRONMENT
1.35 ratchov 594: .Bl -tag -width "AUDIODEVICE" -compact
1.24 jmc 595: .It Ev AUDIODEVICE
1.57 ratchov 596: .Xr sndio 7
597: audio device to use if the
1.50 ratchov 598: .Fl f
599: option is not specified.
1.9 millert 600: .El
1.16 ratchov 601: .Sh EXAMPLES
602: The following will mix and play two stereo streams,
603: the first at 48kHz and the second at 44.1kHz:
604: .Bd -literal -offset indent
605: $ aucat -r 48000 -i file1.raw -r 44100 -i file2.raw
606: .Ed
607: .Pp
608: The following will record channels 2 and 3 into one stereo file and
609: channels 6 and 7 into another stereo file using a 96kHz sampling rate for
610: both:
611: .Bd -literal -offset indent
1.26 ratchov 612: $ aucat -r 96000 -C 2:3 -o file1.raw -C 6:7 -o file2.raw
1.42 ratchov 613: .Ed
614: .Pp
1.43 jmc 615: The following will split a stereo file into two mono files:
1.42 ratchov 616: .Bd -literal -offset indent
617: $ aucat -n -i stereo.wav -C 0:0 -o left.wav -C 1:1 -o right.wav
1.16 ratchov 618: .Ed
619: .Pp
1.35 ratchov 620: The following will start
621: .Nm
1.40 jmc 622: in server mode using default parameters, but will create an
1.57 ratchov 623: additional sub-device for output to channels 2:3 only (rear speakers
624: on most cards), exposing the
625: .Pa aucat:0
626: and
627: .Pa aucat:0.rear
628: devices:
1.35 ratchov 629: .Bd -literal -offset indent
1.45 ratchov 630: $ aucat -l -s default -c 2:3 -s rear
1.35 ratchov 631: .Ed
632: .Pp
633: The following will start
634: .Nm
1.57 ratchov 635: in server mode creating the default sub-device with low volume and
636: an additional sub-device for high volume output, exposing the
637: .Pa aucat:0
638: and
639: .Pa aucat:0.max
640: devices:
1.35 ratchov 641: .Bd -literal -offset indent
1.45 ratchov 642: $ aucat -l -v 65 -s default -v 127 -s max
1.16 ratchov 643: .Ed
1.2 kstailey 644: .Sh SEE ALSO
1.12 jmc 645: .Xr audioctl 1 ,
1.17 jmc 646: .Xr cdio 1 ,
1.9 millert 647: .Xr mixerctl 1 ,
1.54 ratchov 648: .Xr audio 4 ,
649: .Xr sndio 7
1.16 ratchov 650: .Sh BUGS
651: The
1.1 kstailey 652: .Nm
1.16 ratchov 653: utility assumes non-blocking I/O for input and output streams.
654: It will not work reliably on files that may block
655: (ordinary files block, pipes don't).
656: .Pp
657: Resampling is low quality; down-sampling especially should be avoided
658: when recording.
659: .Pp
660: Processing is done using 16-bit arithmetic,
661: thus samples with more than 16 bits are rounded.
1.17 jmc 662: 16 bits (i.e. 97dB dynamic) are largely enough for most applications though.
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