Provided by: jackd_0.118+svn3796-1ubuntu2_i386 bug

NAME

       jackd - JACK Audio Connection Kit sound server

SYNOPSIS

       jackd [options] -d backend [backend-parameters]
       jackd --help

DESCRIPTION

       jackd  is  the  JACK  audio  server daemon, a low-latency audio server.
       Originally written for the GNU/Linux operating system, it also supports
       Mac  OS  X  and  various  Unix platforms.  JACK can connect a number of
       different client applications to an  audio  device  and  also  to  each
       other.   Most  clients  are external, running in their own processes as
       normal applications.  JACK also supports internal  clients,  which  run
       within the jackd process using a loadable "plugin" interface.

       JACK differs from other audio servers in being designed from the ground
       up  for  professional  audio  work.   It  focuses  on  two  key  areas:
       synchronous execution of all clients, and low latency operation.

       For   the  latest  JACK  information,  please  consult  the  web  site,
       <http://www.jackaudio.org>.

OPTIONS

       -d, --driver backend [backend-parameters ]
              Select  the  audio  interface  backend.   The  current  list  of
              supported  backends is: alsa, coreaudio, dummy, freebob, oss sun
              and portaudio.  They are not all  available  on  all  platforms.
              All backend-parameters are optional.

       -h, --help
              Print  a  brief usage message describing the main jackd options.
              These do not include backend-parameters, which are listed  using
              the  --help  option  for  each specific backend.  Examples below
              show how to list them.

       -m, --no-mlock
              Do not attempt to lock memory, even if --realtime.

       -n, --name server-name
              Name this jackd instance server-name.  If unspecified, this name
              comes  from  the  $JACK_DEFAULT_SERVER environment variable.  It
              will be "default" if that is not defined.

       -p, --port-max  n
              Set the maximum number of ports the JACK server can manage.  The
              default value is 256.

       --replace-registry
              Remove  the  shared  memory  registry  used  by  all JACK server
              instances before startup. This should rarely  be  used,  and  is
              intended  only for occasions when the structure of this registry
              changes in ways  that  are  incompatible  across  JACK  versions
              (which is rare).

       -R, --realtime
              Use  realtime  scheduling  (default  = true). This is needed for
              reliable low-latency performance.  On many systems, it  requires
              jackd  to  run  with  special  scheduler  and  memory allocation
              privileges, which may be obtained in several ways.

       -r, --no-realtime
              Do not use realtime scheduling.

       -P, --realtime-priority int
              When running --realtime, set the scheduler priority to int.

       --silent
              Silence any output during operation.

       -T, --temporary
              Exit once all clients have closed their connections.

       -t, --timeout int
              Set client timeout limit in milliseconds.  The  default  is  500
              msec.   In realtime mode the client timeout must be smaller than
              the watchdog timeout (5000 msec).

       -Z, --nozombies
              Prevent JACK from ever kicking out clients because they were too
              slow.   This cancels the effect any specified timeout value, but
              JACK and its clients are still subject to the supervision of the
              watchdog thread or its equivalent.

       -u, --unlock
              Unlock libraries GTK+, QT, FLTK, Wine.

       -v, --verbose
              Give verbose output.

       -c, --clocksource ( c(ycle) |  h(pet)  |  s(ystem) )
              Select  a specific wall clock (Cycle Counter, HPET timer, System
              timer).

       -V, --version
              Print the current JACK version number and exit.

   ALSA BACKEND OPTIONS
       -C, --capture [ name ]
              Provide only capture ports,  unless  combined  with  -D  or  -P.
              Parameterally set capture device name.

       -d, --device name
              The  ALSA  pcm  device  name to use.  If none is specified, JACK
              will  use  "hw:0",  the   first   hardware   card   defined   in
              /etc/modules.conf.

       -z, --dither [rectangular,triangular,shaped,none]
              Set  dithering  mode.  If none or unspecified, dithering is off.
              Only the first letter of the mode name is required.

       -D, --duplex
              Provide both capture and playback ports.  Defaults to on  unless
              only one of -P or -C is specified.

       -h, --help Print a brief usage message describing only the
              alsa backend parameters.

       -M, --hwmeter
              Enable   hardware   metering   for   devices  that  support  it.
              Otherwise, use software metering.

       -H, --hwmon
              Enable hardware monitoring of capture ports.  This is  a  method
              for  obtaining  "zero  latency"  monitoring  of audio input.  It
              requires support in hardware and from the underlying ALSA device
              driver.

              When   enabled,  requests  to  monitor  capture  ports  will  be
              satisfied  by  creating  a  direct  signal  path  between  audio
              interface input and output connectors, with no processing by the
              host computer at all.  This offers the lowest  possible  latency
              for the monitored signal.

              Presently (March 2003), only the RME Hammerfall series and cards
              based on the ICE1712 chipset (M-Audio  Delta  series,  Terratec,
              and others) support --hwmon.  In the future, some consumer cards
              may also be supported by modifying their mixer settings.

              Without --hwmon, port monitoring requires  JACK  to  read  audio
              into system memory, then copy it back out to the hardware again,
              imposing  the  basic  JACK  system  latency  determined  by  the
              --period and --nperiods parameters.

       -i, --inchannels int
              Number  of  capture  channels.   Default is maximum supported by
              hardware.

       -n, --nperiods int
              Specify the number of periods of playback latency.  In  seconds,
              this corresponds to --nperiods times --period divided by --rate.
              The default is 2, the  minimum  allowable.   For  most  devices,
              there is no need for any other value with the --realtime option.
              Without realtime privileges or with boards providing  unreliable
              interrupts  (like ymfpci), a larger value may yield fewer xruns.
              This can also help if the  system  is  not  tuned  for  reliable
              realtime scheduling.

              For  most ALSA devices, the hardware buffer has exactly --period
              times --nperiods frames.  Some devices demand a  larger  buffer.
              If  so, JACK will use the smallest possible buffer containing at
              least --nperiods, but the playback latency does not increase.

              For USB audio devices it is recommended to use  -n  3.  Firewire
              devices  supported  by  FFADO  (formerly Freebob) are configured
              with -n 3 by default.

       -o, --outchannels int
              Number of playback channels.  Default is  maximum  supported  by
              hardware.

       -P, --playback [ name ]
              Provide  only  playback  ports,  unless  combined with -D or -C.
              Optionally set playback device name.

       -p, --period int
              Specify the number of frames between JACK process() calls.  This
              value  must  be  a  power of 2, and the default is 1024.  If you
              need low latency, set -p as low as you  can  go  without  seeing
              xruns.   A  larger  period size yields higher latency, but makes
              xruns less likely.  The  JACK  capture  latency  in  seconds  is
              --period divided by --rate.

       -r, --rate int
              Specify the sample rate.  The default is 48000.

       -S, --shorts
              Try  to  configure  card  for  16-bit samples first, only trying
              32-bits if unsuccessful.  Default is to prefer 32-bit samples.

       -s, --softmode
              Ignore xruns reported by the ALSA driver.  This makes JACK  less
              likely  to  disconnect  unresponsive  ports when running without
              --realtime.

       -X, --midi [seq|raw]
              Specify which ALSA MIDI system to provide access to.  Using  raw
              will  provide  a  set of JACK MIDI ports that correspond to each
              raw ALSA device on the machine. Using seq will provide a set  of
              JACK  MIDI ports that correspond to each ALSA "sequencer" client
              (which includes each hardware MIDI port  on  the  machine).  raw
              provides  slightly  better  performance but does not permit JACK
              MIDI  communication  with  software  written  to  use  the  ALSA
              "sequencer" API.

   COREAUDIO BACKEND PARAMETERS
       -c --channel
              Maximum number of channels (default: 2)

       -i --channelin
              Maximum number of input channels (default: 2)

       -o --channelout
              Maximum number of output channels (default: 2)

       -C --capture
              Whether or not to capture (default: true)

       -P --playback
              Whether or not to playback (default: true)

       -D --duplex
              Capture and playback (default: true)

       -r --rate
              Sample rate (default: 44100)

       -p --period
              Frames per period (default: 128). Must be a power of 2.

       -n --name
              Driver name (default: none)

       -I --id
              Audio Device ID (default: 0)

   DUMMY BACKEND PARAMETERS
       -C, --capture int
              Specify number of capture ports. The default value is 2.

       -P, --playback int
              Specify number of playback ports. The default value is 2.

       -r, --rate int
              Specify sample rate. The default value is 48000.

       -p, --period int
              Specify the number of frames between JACK process() calls.  This
              value must be a power of 2, and the default  is  1024.   If  you
              need  low  latency,  set  -p as low as you can go without seeing
              xruns.  A larger period size yields higher  latency,  but  makes
              xruns  less  likely.   The  JACK  capture  latency in seconds is
              --period divided by --rate.

       -w, --wait int
              Specify number of usecs to wait between engine  processes.   The
              default value is 21333.

   NET BACKEND PARAMETERS
        -i, --audio-ins int
              Number of capture channels (default: 2)

        -o, --audio-outs int
              Number of playback channels (default: 2)

        -I, --midi-ins int
              Number of midi capture channels (default: 1)

       -O, --midi-outs int
              Number of midi playback channels (default: 1)

        -r, --rate int
              Sample rate (default: 48000)

       -p, --period int
              Frames per period (default: 1024)

       -n, --num-periods int
              Network latency setting in no. of periods (default: 5)

       -l, --listen-port int
              The  socket  port we are listening on for sync packets (default:
              3000)

       -f, --factor int
              Factor for sample rate reduction (default: 1)

       -u, --upstream-factor int
              Factor for sample rate reduction on the upstream (default: 0)

       -c, --celt int
              sets celt encoding and number of kbits per channel (default: 0)

       -b, --bit-depth int
              Sample bit-depth (0 for float, 8 for  8bit  and  16  for  16bit)
              (default: 0)

       -t, --transport-sync int
              Whether to slave the transport to the master transport (default:
              true)

       -a, --autoconf int
              Whether to use Autoconfig, or just start. (default: true)

       -R, --redundancy int
              Send packets N times (default: 1)

       -e, --native-endian int
              Dont convert samples to network byte order. (default: false)

       -J, --jitterval int
              attempted jitterbuffer microseconds on master (default: 0)

       -D, --always-deadline int
              always use deadline (default: false)

   OSS BACKEND PARAMETERS
       -r, --rate int
              Specify the sample rate.  The default is 48000.

       -p, --period int
              Specify the number of frames between JACK process() calls.  This
              value  must  be  a  power of 2, and the default is 1024.  If you
              need low latency, set -p as low as you  can  go  without  seeing
              xruns.   A  larger  period size yields higher latency, but makes
              xruns less likely.  The  JACK  capture  latency  in  seconds  is
              --period divided by --rate.

       -n, --nperiods int
              Specify  the  number  of  periods  in  the hardware buffer.  The
              default is 2.  The period size (-p) times --nperiods times  four
              is  the  JACK  buffer size in bytes.  The JACK output latency in
              seconds is --nperiods times --period divided by --rate.

       -w, --wordlength int
              Specify the sample size in bits. The default is 16.

       -i, --inchannels int
              Specify how many channels to capture (default: 2)

       -o, --outchannels int
              Specify number of playback channels (default: 2)

       -C, --capture device_file
              Specify input device for capture (default: /dev/dsp)

       -P, --playback device_file
              Specify output device for playback (default: /dev/dsp)

       -b, --ignorehwbuf boolean
              Specify, whether to ignore hardware period size (default: false)

   SUN BACKEND PARAMETERS
       -r, --rate int
              Specify the sample rate.  The default is 48000.

       -p, --period int
              Specify the number of frames between JACK process() calls.  This
              value must be a power of 2, and the default  is  1024.   If  you
              need  low  latency,  set  -p as low as you can go without seeing
              xruns.  A larger period size yields higher  latency,  but  makes
              xruns  less  likely.   The  JACK  capture  latency in seconds is
              --period divided by --rate.

       -n, --nperiods int
              Specify the number of  periods  in  the  hardware  buffer.   The
              default  is 2.  The period size (-p) times --nperiods times four
              (assuming 2 channels 16-bit samples) is the JACK buffer size  in
              bytes.   The  JACK output latency in seconds is --nperiods times
              --period divided by --rate.

       -w, --wordlength int
              Specify the sample size in bits. The default is 16.

       -i, --inchannels int
              Specify how many channels to capture (default: 2)

       -o, --outchannels int
              Specify number of playback channels (default: 2)

       -C, --capture device_file
              Specify input device for capture (default: /dev/audio)

       -P, --playback device_file
              Specify output device for playback (default: /dev/audio)

       -b, --ignorehwbuf boolean
              Specify, whether to ignore hardware period size (default: false)

   PORTAUDIO BACKEND PARAMETERS
       -c --channel
              Maximum  number  of  channels  (default:  all available hardware
              channels)

       -i --channelin
              Maximum  number  of  input  channels  (default:  all   available
              hardware channels)

       -o --channelout
              Maximum  number  of  output  channels  (default:  all  available
              hardware channels)

       -C --capture
              Whether or not to capture (default: true)

       -P --playback
              Whether or not to playback (default: true)

       -D --duplex
              Capture and playback (default: true)

       -r --rate
              Sample rate (default: 48000)

       -p --period
              Frames per period (default: 1024). Must be a power of 2.

       -n --name
              Driver name (default: none)

       -z --dither
              Dithering mode (default: none)

EXAMPLES

       Print usage message for the parameters specific to each backend.

              jackd -d alsa --help
              jackd -d coreaudio --help
              jackd -d net --help
              jackd -d dummy --help
              jackd -d firewire --help
              jackd -d freebob --help
              jackd -d oss --help
              jackd -d sun --help
              jackd -d portaudio --help

       Run the JACK  daemon  with  realtime  priority  using  the  first  ALSA
       hardware card defined in /etc/modules.conf.

              jackstart --realtime --driver=alsa

       Run  the  JACK daemon with low latency giving verbose output, which can
       be helpful for trouble-shooting system latency problems.  A  reasonably
       well-tuned  system  with a good sound card and a low-latency kernel can
       handle these values reliably.  Some can do better.   If  you  get  xrun
       messages,  try a larger buffer.  Tuning a system for low latency can be
       challenging.  The JACK FAQ,  http://jackit.sourceforge.net/docs/faq.php
       has some useful suggestions.

              jackstart -Rv -d alsa -p 128 -n 2 -r 44100

       Run jackd with realtime priority using the "sblive" ALSA device defined
       in ~/.asoundrc.  Apply shaped dithering to playback audio.

              jackd -R -d alsa -d sblive --dither=shaped

       Run jackd with no special privileges using  the  second  ALSA  hardware
       card  defined  in  /etc/modules.conf.   Any  xruns reported by the ALSA
       backend will be ignored.  The larger buffer  helps  reduce  data  loss.
       Rectangular dithering will be used for playback.

              jackd -d alsa -d hw:1 -p2048 -n3 --softmode -zr

       Run jackd in full-duplex mode using the ALSA hw:0,0 device for playback
       and the hw:0,2 device for capture.

              jackd -d alsa -P hw:0,0 -C hw:0,2

       Run jackd in playback-only mode using the ALSA hw:0,0 device.

              jackd -d alsa -P hw:0,0

ENVIRONMENT

       JACK is evolving a mechanism for automatically starting the server when
       needed.   Any client started without a running JACK server will attempt
       to start one itself using the command line found in the first  line  of
       $HOME/.jackdrc  if  it  exists,  or  /etc/jackdrc  if  it does not.  If
       neither file exists, a built-in default command will be used, including
       the -T flag, which causes the server to shut down when all clients have
       exited.

       As a transition, this only happens when $JACK_START_SERVER  is  defined
       in  the  environment  of  the calling process.  In the future this will
       become normal behavior.  In either case, defining $JACK_NO_START_SERVER
       disables this feature.

       To   change   where   JACK   looks   for   the   backend  drivers,  set
       $JACK_DRIVER_DIR.

       $JACK_DEFAULT_SERVER  specifies  the  default  server  name.   If   not
       defined,  the  string  "default"  is  used.  If set in their respective
       environments, this affects jackd unless its --name  parameter  is  set,
       and   all   JACK   clients   unless  they  pass  an  explicit  name  to
       jack_client_open().

SEE ALSO:

       http://www.jackaudio.org
       The official JACK website with news, docs and a list of JACK clients.

       http://jackaudio.org/email
       The  JACK  developers’  mailing  list.   Subscribe,  to  take  part  in
       development  of JACK or JACK clients.  User questions are also welcome,
       there is no user-specific mailing list.

       http://www.jackosx.com/
       Tools specific to the Mac OS X version of JACK.

       http://www.alsa-project.org
       The Advanced Linux Sound Architecture.

BUGS

       Please report bugs to
       http://trac.jackaudio.org/

AUTHORS

       Architect and original implementor: Paul Davis

       Original design Group: Paul Davis, David Olofson, Kai  Vehmanen,  Benno
       Sennoner,  Richard  Guenther,  and  other  members  of  the Linux Audio
       Developers group.

       Programming: Paul Davis, Jack O’Quin,  Taybin  Rutkin,  Stephane  Letz,
       Fernando  Pablo  Lopez-Lezcano,  Steve Harris, Jeremy Hall, Andy Wingo,
       Kai Vehmanen, Melanie Thielker, Jussi Laako,  Tilman  Linneweh,  Johnny
       Petrantoni, Torben Hohn.

       Manpage  written  by  Stefan  Schwandter,  Jack  O’Quin  and  Alexandre
       Prokoudine.