mirror of https://github.com/ericonr/sndio.git
hide server bits
This commit is contained in:
Alexandre Ratchov
parent
eff8e25982
commit
41372817a0
461
aucat/aucat.1
461
aucat/aucat.1
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@ -18,14 +18,12 @@
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.Dt AUCAT 1
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.Os
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.Sh NAME
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.Nm aucat ,
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.Nm sndiod
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.Nd audio/MIDI server and stream manipulation tool
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.Nm aucat
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.Nd audio/MIDI stream manipulation tool
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.Sh SYNOPSIS
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.Nm aucat
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.Bk -words
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.Op Fl dn
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.Op Fl b Ar nframes
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.Op Fl dMn
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.Op Fl C Ar min : Ns Ar max
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.Op Fl c Ar min : Ns Ar max
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.Op Fl e Ar enc
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@ -41,149 +39,56 @@
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.Op Fl v Ar volume
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.Op Fl w Ar flag
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.Op Fl x Ar policy
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.Op Fl z Ar nframes
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.Ek
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.Nm sndiod
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.Bk -words
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.Op Fl dM
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.Op Fl a Ar flag
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.Op Fl b Ar nframes
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.Op Fl C Ar min : Ns Ar max
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.Op Fl c Ar min : Ns Ar max
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.Op Fl e Ar enc
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.Op Fl f Ar device
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.Op Fl j Ar flag
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.Op Fl L Ar addr
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.Op Fl m Ar mode
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.Op Fl q Ar port
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.Op Fl r Ar rate
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.Op Fl s Ar name
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.Op Fl t Ar mode
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.Op Fl U Ar unit
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.Op Fl v Ar volume
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.Op Fl w Ar flag
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.Op Fl x Ar policy
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.Op Fl z Ar nframes
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.Ek
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.Sh DESCRIPTION
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The
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.Nm sndiod
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daemon is an intermediate layer between
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audio or MIDI programs and the hardware.
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It performs the necessary audio processing to
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allow any program to work on any supported hardware.
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By default,
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.Nm sndiod
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accepts connections from programs
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running on the same system only;
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it initializes only when programs are using its services,
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allowing
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.Nm sndiod
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to consume a negligible amount of system resources the rest of the time.
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Systems with no audio hardware can use
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.Nm sndiod
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to keep hot-pluggable devices usable by default at
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virtually no cost.
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.Pp
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.Nm sndiod
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operates as follows: it exposes at least one
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.Em sub-device
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that any number of audio programs can connect to and use as if it were
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audio hardware.
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.Nm
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utility can play, record, mix, and convert audio files.
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During playback,
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.Nm sndiod
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receives audio data concurrently from all programs, mixes it and sends
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the result to the hardware device.
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.Nm
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reads audio data concurrently from all played files, mixes it and sends
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the result to the device.
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Similarly, during recording it duplicates audio data recorded
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from the device and sends it to all programs.
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Since audio data flows through the
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.Nm sndiod
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process, it has the opportunity to process audio data on the fly:
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from the device and stores it into corresponding files.
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It can process audio data on the fly:
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.Pp
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.Bl -bullet -offset indent -compact
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.It
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Change the sound encoding to overcome incompatibilities between
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software and hardware.
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Change the sound encoding.
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.It
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Route the sound from one channel to another,
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join stereo or split mono.
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.It
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Control the per-application playback volume as well as the
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master volume.
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Control the per-file playback volume.
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.It
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Monitor the sound being played, allowing one program to record
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what other programs play.
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Monitor the sound being played, allowing to playback mix
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to be record.
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.El
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.Pp
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Processing is configured on a per sub-device basis, meaning that
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the sound of all programs connected to the same sub-device will be
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processed according to the same configuration.
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Multiple sub-devices can be defined, allowing multiple configurations
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to coexist.
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The user selects the configuration a given program will use
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by selecting the sub-device the program uses.
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.Pp
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.Nm sndiod
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can expose a MIDI port that can be used as a MIDI thru box
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(aka a
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.Dq hub
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for MIDI messages),
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allowing any program to send MIDI messages to
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MIDI hardware or to another program in a uniform way.
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Hardware ports can be subscribed to such MIDI thru boxes,
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allowing multiple programs to share the MIDI port.
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.Pp
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Finally,
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.Nm sndiod
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exposes a control MIDI port usable for:
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.Nm
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can accept MIDI messages usable for:
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.Pp
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.Bl -bullet -offset indent -compact
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.It
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Volume control.
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.It
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Common clock source for audio and MIDI programs.
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.It
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Start, stop and relocate groups of audio programs.
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Start, stop and relocate playback and recording.
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.El
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.Pp
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The
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For historic reasons
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.Nm
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utility can play, record, mix, and convert regular audio files.
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It has the same processing capabilities as
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.Nm sndiod .
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has the same audio server capability as
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.Xr sndiod 1 ,
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enabled when no files to play or record are provided.
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Both operate the same way, except that the former processes audio data stored
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in files, while the latter processes audio data provided or consumed by
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programs.
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Instead of a list of sub-devices,
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.Nm
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is given a list of files to play or record.
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Hence it has the same server-centric options described in
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.Xr sndiod 1 .
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.Pp
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The options are as follows:
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.Bl -tag -width Ds
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.It Fl a Ar flag
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Control whether
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.Nm sndiod
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opens the audio device only when needed or keeps it open all the time.
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This applies to MIDI ports controlling the device as well.
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If the flag is
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.Va on
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then the device is kept open all the time, ensuring no other program can
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steal it.
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If the flag is
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.Va off ,
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then it's automatically closed, allowing other programs to have direct
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access to the device, or the device to be disconnected.
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The default is
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.Va off ,
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except for the default device.
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.It Fl b Ar nframes
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The buffer size of the audio device in frames.
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A frame consists of one sample for each channel in the stream.
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This is the number of frames that will be buffered before being played
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and thus controls the playback latency.
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The default is 7680 or twice the block size
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.Pq Fl z ,
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if the block size is set.
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.It Xo
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.Fl C Ar min : Ns Ar max ,
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.Fl c Ar min : Ns Ar max
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@ -193,22 +98,16 @@ respectively.
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The default is 0:1, i.e. stereo.
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.It Fl d
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Increase log verbosity.
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.Nm sndiod
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logs on
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.Em stderr
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until it daemonizes.
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.It Fl e Ar enc
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Encoding of the playback or recording stream (see below).
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The default is signed, 16-bit, native byte order.
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.It Fl f Ar device
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Add this
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Use this
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.Xr sndio 7
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audio device to devices used for playing and/or recording.
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Preceding per-device options
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.Pq Fl abwz
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apply to this device.
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audio device.
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Preceding per-device options apply to this device.
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Streams
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.Pq Fl ios
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.Pq Fl io
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and control MIDI ports
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.Pq Fl q
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that are applied after will be attached to this device.
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@ -237,24 +136,6 @@ For instance, this feature could be used to request mono streams to
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be sent on multiple outputs or to record a stereo input into a mono stream.
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The default is
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.Ar on .
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.It Fl L Ar addr
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Specify a local network address
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.Nm sndiod
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should listen;
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.Nm sndiod
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will listen on TCP port 11025+n, where n is the unit number
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specified with
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.Fl U .
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Without this option,
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.Nm sndiod
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listens on the
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.Ux Ns -domain
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socket only, and is not reachable from any network.
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If the option argument is
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.Sq -
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then
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.Nm sndiod
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will accept connections from any address.
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.It Fl M
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Create a MIDI thru box
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.Pq i.e. MIDI-only pseudo device .
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@ -269,11 +150,6 @@ preceded by
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.Fl m Ar midi
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.Pc
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can be attached to it.
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Exposed sub-devices by
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.Nm sndiod
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behave like software MIDI ports,
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allowing any MIDI-capable application to send MIDI messages to
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MIDI hardware or to another application in a uniform way.
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.It Fl m Ar mode
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Set the stream mode.
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Valid modes are
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@ -306,10 +182,8 @@ If the option argument is
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.Sq -
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then standard output will be used.
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.It Fl q Ar port
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Expose the audio device clock on this
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.Xr sndio 7
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MIDI port and allow audio device properties to be controlled
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through MIDI.
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Allow audio device properties to be controlled
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through this MIDI port.
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This includes per-stream volumes and the ability to
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synchronously start, stop and relocate streams created in
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MIDI Machine
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@ -318,23 +192,6 @@ Control (MMC) slave mode
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.It Fl r Ar rate
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Sample rate in Hertz of the stream.
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The default is 48000.
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.It Fl s Ar name
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Add
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.Ar name
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to the list of sub-devices to expose.
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This allows clients to use
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.Nm sndiod
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instead of the physical audio device for audio input and output
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in order to share the physical device with other clients.
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Defining multiple sub-devices allows splitting a physical audio device
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into logical devices having different properties (e.g. channel ranges).
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The given
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.Ar name
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corresponds to the
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.Dq option
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part of the
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.Xr sndio 7
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device name string.
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.It Fl t Ar mode
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Select the way streams are controlled by MIDI Machine Control (MMC)
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messages.
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@ -343,37 +200,15 @@ If the mode is
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(the default), then streams are not affected by MMC messages.
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If the mode is
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.Va slave ,
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then streams are started synchronously by MMC start messages;
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additionally, the server clock is exposed as MIDI Time Code (MTC)
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messages allowing MTC-capable software or hardware to be synchronized
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to audio streams.
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.It Fl U Ar unit
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Unit number to use when running in server mode.
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Each
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.Nm sndiod
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server instance has an unique unit number,
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used in
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.Xr sndio 7
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device names.
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The default is 0.
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The unit number must be set before any
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.Fl L
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is used.
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then streams are started synchronously by MMC start messages.
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.It Fl v Ar volume
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Software volume attenuation of the playback stream.
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The value must be between 1 and 127,
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corresponding to \-42dB and \-0dB attenuation in 1/3dB steps.
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In server mode, clients inherit this parameter.
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Reducing the volume in advance allows a client's volume to stay independent
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from the number of clients as long as their number is small enough.
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18 volume units (i.e. \-6dB attenuation) allows the number
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of playback streams to be doubled.
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The default is 127 i.e. no attenuation.
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.It Fl w Ar flag
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Control
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.Nm
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and
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.Nm sndiod
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behaviour when the maximum volume of the hardware is reached
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and a new stream is connected.
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This happens only when stream volumes
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@ -417,36 +252,19 @@ the
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.Dq ignore
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action is disabled for any stream connected to it
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to ensure proper synchronization.
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.It Fl z Ar nframes
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The audio device block size in frames.
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This is the number of frames between audio clock ticks,
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i.e. the clock resolution.
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If a stream is created with the
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.Fl t
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option,
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and MTC is used for synchronization, the clock
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resolution must be 96, 100 or 120 ticks per second for maximum
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accuracy.
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For instance, 100 ticks per second at 48000Hz corresponds
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to a 480 frame block size.
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The default is 960 or half of the buffer size
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.Pq Fl b ,
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if the buffer size is set.
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.El
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.Pp
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On the command line,
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per-device parameters
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.Pq Fl abwz
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must precede the device definition
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per-device parameters must precede the device definition
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.Pq Fl fMn ,
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and per-stream parameters
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.Pq Fl Ccehjmrtvx
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must precede the stream definition
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.Pq Fl ios .
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.Pq Fl io .
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MIDI ports
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.Pq Fl q
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and stream definitions
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.Pq Fl ios
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.Pq Fl io
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must follow the definition of the device
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.Pq Fl fMn
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to which they are attached.
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@ -456,34 +274,8 @@ If no audio devices
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are specified,
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settings are applied as if
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the default device is specified.
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If no
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.Nm sndiod
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sub-devices
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.Pq Fl s
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are specified for a device, a default server sub-device is
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created attached to it.
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If a device
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.Pq Fl fMn
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is defined twice, both definitions are merged:
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parameters of the first one are used but streams
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.Pq Fl ios
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and MIDI control ports
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.Pq Fl q
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of both definitions are created.
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The default
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.Xr sndio 7
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device used by
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.Nm sndiod
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is
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.Pa rsnd/0 ,
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and the default sub-device exposed by
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.Nm sndiod
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is
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.Pa snd/0 .
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.Pp
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If
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.Nm sndiod
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or
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.Nm aucat
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is sent
|
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.Dv SIGHUP ,
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|
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@ -571,34 +363,12 @@ signed 18-bit, packed in 3 bytes, little endian
|
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.It u18be3
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unsigned 18-bit, packed in 3 bytes, big endian
|
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.El
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.Sh SERVER MODE
|
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.Nm sndiod
|
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can be used
|
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to overcome hardware limitations and allow applications
|
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to run on fixed sample rate devices or on devices
|
||||
supporting only unusual encodings.
|
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.Pp
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Certain applications, such as synthesis software,
|
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require a low latency audio setup.
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To reduce the probability of buffer underruns or overruns, especially
|
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on busy machines, the server can be started by the super-user, in which
|
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case it will run with higher priority.
|
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Any user will still be able to connect to it,
|
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but for privacy reasons only one user may have
|
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connections to it at a given time.
|
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.Sh MIDI CONTROL
|
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.Nm
|
||||
can expose the audio device clock on registered
|
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MIDI ports
|
||||
can be controlled through MIDI
|
||||
.Pq Fl q
|
||||
and allows audio device properties to be controlled
|
||||
through MIDI.
|
||||
Additionally,
|
||||
.Nm sndiod
|
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creates a MIDI port with the same name as the exposed audio
|
||||
sub-device to which MIDI programs can connect.
|
||||
.Pp
|
||||
A MIDI channel is assigned to each stream, and the volume
|
||||
as follows:
|
||||
a MIDI channel is assigned to each stream, and the volume
|
||||
is changed using the standard volume controller (number 7).
|
||||
Similarly, when the audio client changes its volume,
|
||||
the same MIDI controller message is sent out; it can be used
|
||||
|
|
@ -613,89 +383,37 @@ Streams created with the
|
|||
option are controlled by the following MMC messages:
|
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.Bl -tag -width relocateXXX -offset indent
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.It relocate
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Streams are relocated to the requested time position
|
||||
relative to the beginning of the stream, at which playback
|
||||
and recording must start.
|
||||
Files are relocated to the requested time position.
|
||||
If the requested position is beyond the end of file,
|
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the stream is temporarly disabled until a valid position is requested.
|
||||
This message is ignored by audio
|
||||
.Nm sndiod
|
||||
clients, but the given time position is sent to MIDI ports as an MTC
|
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.Dq "full frame"
|
||||
message forcing all MTC-slaves to relocate to the given
|
||||
position (see below).
|
||||
playback of the file is temporarly disabled until a valid
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position is requested.
|
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.It start
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||||
Put all streams in starting mode.
|
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In this mode,
|
||||
.Nm sndiod
|
||||
or
|
||||
.Nm aucat
|
||||
waits for all streams to become ready
|
||||
to start, and then starts them synchronously.
|
||||
Once started, new streams can be created
|
||||
.Pq Nm sndiod
|
||||
but they will be blocked
|
||||
until the next stop-to-start transition.
|
||||
Files are started.
|
||||
.It stop
|
||||
Put all streams in stopped mode (the default).
|
||||
In this mode, any stream attempting to start playback or recording
|
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is paused.
|
||||
Files
|
||||
.Pq Nm aucat
|
||||
are stopped and rewound back to the starting position,
|
||||
while client streams
|
||||
.Pq Nm sndiod
|
||||
that are already
|
||||
started are not affected until they stop and try to start again.
|
||||
.El
|
||||
.Pp
|
||||
Streams created with the
|
||||
.Fl t
|
||||
option export the
|
||||
.Nm sndiod
|
||||
device clock using MTC, allowing non-audio
|
||||
software or hardware to be synchronized to the audio stream.
|
||||
Maximum accuracy is achieved when the number of blocks per
|
||||
second is equal to one of the standard MTC clock rates (96, 100 and 120Hz).
|
||||
The following sample rates
|
||||
.Pq Fl r
|
||||
and block sizes
|
||||
.Pq Fl z
|
||||
are recommended:
|
||||
.Pp
|
||||
.Bl -bullet -offset indent -compact
|
||||
.It
|
||||
44100Hz, 441 frames (MTC rate is 100Hz)
|
||||
.It
|
||||
48000Hz, 400 frames (MTC rate is 120Hz)
|
||||
.It
|
||||
48000Hz, 480 frames (MTC rate is 100Hz)
|
||||
.It
|
||||
48000Hz, 500 frames (MTC rate is 96Hz)
|
||||
Files are stopped and rewound back to the starting position.
|
||||
.El
|
||||
.Pp
|
||||
MIDI control is intended to be used together with
|
||||
.Xr sndiod 1 .
|
||||
For instance, the following command will create two devices:
|
||||
the default
|
||||
.Va snd/0
|
||||
and a MIDI-controlled
|
||||
and a MMC-controlled one
|
||||
.Va snd/0.mmc :
|
||||
.Bd -literal -offset indent
|
||||
$ sndiod -r 48000 -z 400 -s default -t slave -s mmc
|
||||
.Ed
|
||||
.Pp
|
||||
Streams connected to
|
||||
Programs using
|
||||
.Va snd/0
|
||||
behave normally, while streams connected to
|
||||
behave normally, while programs using
|
||||
.Va snd/0.mmc
|
||||
wait for the MMC start signal and start synchronously.
|
||||
Regardless of which device a stream is connected to,
|
||||
its playback volume knob is exposed.
|
||||
.Pp
|
||||
For instance, the following command will play a file on the
|
||||
Then, the following command will play a file on the
|
||||
.Va snd/0.mmc
|
||||
audio device, and give full control to MIDI software or hardware
|
||||
audio device, giving full control to MIDI software or hardware
|
||||
connected to the
|
||||
.Va snd/0.thru
|
||||
.Va midithru/0
|
||||
MIDI port:
|
||||
.Bd -literal -offset indent
|
||||
$ aucat -f snd/0.mmc -t slave -q midithru/0 -i file.wav
|
||||
|
|
@ -704,20 +422,13 @@ $ aucat -f snd/0.mmc -t slave -q midithru/0 -i file.wav
|
|||
At this stage,
|
||||
.Nm
|
||||
will start, stop and relocate automatically following all user
|
||||
actions in the MIDI sequencer.
|
||||
Note that the sequencer must use
|
||||
actions in the MIDI sequencer, assuming it's configured to
|
||||
transmit MMC on
|
||||
.Va midithru/0 .
|
||||
Furthermore, the MIDI sequencer could be configured to use the
|
||||
.Va snd/0
|
||||
as the MTC source, i.e. the audio server, not the audio player.
|
||||
.Sh ENVIRONMENT
|
||||
.Bl -tag -width "AUCAT_COOKIE" -compact
|
||||
.It Ev AUCAT_COOKIE
|
||||
File containing user's session cookie.
|
||||
.It Ev AUDIODEVICE
|
||||
.Xr sndio 7
|
||||
audio device to use if the
|
||||
.Fl f
|
||||
option is not specified.
|
||||
.El
|
||||
port as MTC clock source, assured to be synchronous to playback of
|
||||
.Pa file.wav .
|
||||
.Sh EXAMPLES
|
||||
Mix and play two stereo streams,
|
||||
the first at 48kHz and the second at 44.1kHz:
|
||||
|
|
@ -737,77 +448,17 @@ Split a stereo file into two mono files:
|
|||
$ aucat -n -j off -i stereo.wav -C 0:0 -o left.wav -C 1:1 \e
|
||||
-o right.wav
|
||||
.Ed
|
||||
.Pp
|
||||
Start server using default parameters, creating an
|
||||
additional sub-device for output to channels 2:3 only (rear speakers
|
||||
on most cards), exposing the
|
||||
.Pa snd/0
|
||||
and
|
||||
.Pa snd/0.rear
|
||||
devices:
|
||||
.Bd -literal -offset indent
|
||||
$ sndiod -s default -c 2:3 -s rear
|
||||
.Ed
|
||||
.Pp
|
||||
Start server creating the default sub-device with low volume and
|
||||
an additional sub-device for high volume output, exposing the
|
||||
.Pa snd/0
|
||||
and
|
||||
.Pa snd/0.max
|
||||
devices:
|
||||
.Bd -literal -offset indent
|
||||
$ sndiod -v 65 -s default -v 127 -s max
|
||||
.Ed
|
||||
.Pp
|
||||
Start server configuring the audio device to use
|
||||
a 48kHz sample frequency, 240-frame block size,
|
||||
and 2-block buffers.
|
||||
The corresponding latency is 10ms, which is
|
||||
the time it takes the sound to propagate 3.5 meters.
|
||||
.Bd -literal -offset indent
|
||||
$ sndiod -r 48000 -b 480 -z 240
|
||||
.Ed
|
||||
.Sh SEE ALSO
|
||||
.Xr audioctl 1 ,
|
||||
.Xr cdio 1 ,
|
||||
.Xr mixerctl 1 ,
|
||||
.Xr sndiod 1 ,
|
||||
.Xr audio 4 ,
|
||||
.Xr sndio 7
|
||||
.Sh BUGS
|
||||
The
|
||||
.Nm
|
||||
utility assumes non-blocking I/O for input and output streams.
|
||||
It will not work reliably on files that may block
|
||||
(ordinary files block, pipes don't).
|
||||
To avoid audio underruns/overruns or MIDI jitter caused by file I/O,
|
||||
it's recommended to use two processes: a
|
||||
.Nm sndiod
|
||||
server handling audio and MIDI I/O and a
|
||||
.Nm
|
||||
client handling disk I/O.
|
||||
.Pp
|
||||
Resampling is low quality; down-sampling especially should be avoided
|
||||
when recording.
|
||||
.Pp
|
||||
Processing is done using 16-bit arithmetic,
|
||||
thus samples with more than 16 bits are rounded.
|
||||
16 bits (i.e. 97dB dynamic) are largely enough for most applications though.
|
||||
.Pp
|
||||
If
|
||||
.Fl a Ar off
|
||||
is used,
|
||||
.Nm sndiod
|
||||
creates sub-devices to expose first
|
||||
and then opens the audio hardware on demand.
|
||||
Technically, this allows
|
||||
.Nm sndiod
|
||||
to attempt to use one of the sub-devices it exposes as an audio device,
|
||||
creating a deadlock.
|
||||
To avoid this,
|
||||
.Fl a Ar off
|
||||
is disabled for the default audio device, but nothing prevents the user
|
||||
from shooting himself in the foot by creating a similar deadlock.
|
||||
.Pp
|
||||
The ability to merge multiple inputs is provided to allow multiple
|
||||
applications producing MIDI data to keep their connection open while
|
||||
idling; it does not replace a fully featured MIDI merger.
|
||||
|
|
|
|||
|
|
@ -98,11 +98,10 @@ volatile sig_atomic_t debug_level = 1;
|
|||
#endif
|
||||
volatile sig_atomic_t quit_flag = 0;
|
||||
|
||||
char aucat_usage[] = "usage: " PROG_AUCAT " [-dlMn] [-a flag] [-b nframes] "
|
||||
"[-C min:max] [-c min:max] [-e enc]\n\t"
|
||||
"[-f device] [-h fmt] [-i file] [-j flag] [-m mode] [-o file]\n\t"
|
||||
"[-q port] [-r rate] [-t mode] [-v volume] [-w flag] [-x policy]\n\t"
|
||||
"[-z nframes]\n";
|
||||
char aucat_usage[] = "usage: " PROG_AUCAT " [-dMn] "
|
||||
"[-C min:max] [-c min:max] [-e enc] [-f device]\n\t"
|
||||
"[-h fmt] [-i file] [-j flag] [-m mode] [-o file] [-q port]\n\t"
|
||||
"[-r rate] [-t mode] [-v volume] [-w flag] [-x policy]\n";
|
||||
|
||||
char sndiod_usage[] = "usage: " PROG_SNDIOD " [-dM] [-a flag] [-b nframes] "
|
||||
"[-C min:max] [-c min:max] [-e enc]\n\t"
|
||||
|
|
@ -429,7 +428,7 @@ main(int argc, char **argv)
|
|||
else
|
||||
prog++;
|
||||
if (strcmp(prog, PROG_AUCAT) == 0) {
|
||||
optstr = "a:b:c:C:de:f:h:i:j:lL:m:Mno:q:r:s:t:U:v:w:x:z:";
|
||||
optstr = "a:b:c:C:de:f:h:i:j:L:m:Mno:q:r:s:t:U:v:w:x:z:";
|
||||
usagestr = aucat_usage;
|
||||
hold = 1;
|
||||
} else if (strcmp(prog, PROG_SNDIOD) == 0) {
|
||||
|
|
|
|||
Loading…
Reference in New Issue