Metadata-Version: 1.1
Name: PagingServer
Version: 15.10.5
Summary: SIP-based Announcement / PA / Paging / Public Address Server system
Home-page: https://github.com/AccelerateNetworks/PagingServer
Author: Dan Ryan, Mike Kazantsev
Author-email: dan@seattlemesh.net, mk.fraggod@gmail.com
License: GPL-2
Description: PagingServer
        ============
        
        SIP-based Announcement / PA / Paging / Public Address Server system.
        
        Main component of this project is a script to run PJSUA_ SIP client connected to
        a JACK_ sound server routing audio to whatever sound cards and speaker sets.
        
        It picks up calls, plays klaxon on speakers, followed by the announcement made
        in that call. Music plays in-between announcements.
        
        Script controls PJSUA and JACK to make them work to that effect.
        
        
        .. contents::
          :backlinks: none
        
        
        
        Usage
        -----
        
        After installation (see below), the script should be configured, providing it
        with at least the SIP account data for the general usage.
        
        Configuration file (`ini format`_) locations:
        
        * paging.conf
        * /etc/paging.conf
        * callpipe.conf
        * /etc/callpipe.conf
        * Paths specified on the command line.
        
        All files will be looked up and parsed in that order, values in next ones
        overriding corresponding ones in the previous and defaults.
        
        See output of ``paging --help`` for info on how to specify additional
        configuration, more up-to-date list of default paths, as well as general
        information for all the other options available.
        
        Provided `paging.example.conf`_ file has all the available
        configuration options and their descriptions.
        
        To see default configuration options, use ``paging --dump-conf-defaults``, and
        run ``paging --dump-conf ...`` to see the actual options being picked-up and
        used at any time.
        
        There are two general (supported) ways to start and run the script:
        
        * In the foreground (non-forking).
        * As a systemd service.
        
        Both are described in more detail below.
        
        
        Start/run in the foreground
        ```````````````````````````
        
        Aka simple non-forking start.
        
        If necessary, start jackd process in the background first::
        
          % jackd -d dummy &>/dev/null &
        
        Then just run the thing as::
        
          % paging
        
        Can be used directly from terminal, or with any init system or daemon manager,
        including systemd, upstart, openrc, runit, daemontools, debian's
        "start-stop-daemon", simple bash scripts, etc.
        
        For systemd in particular, see the "Running as a systemd service" section below.
        
        Running from terminal to understand what's going on, these options might be also
        useful::
        
          % paging --debug
          % paging --debug --pjsua-log-level 10
          % paging --dump-conf
        
        See also "Installation" and "Audio configuration" sections below.
        
        
        Running as a systemd service
        ````````````````````````````
        
        This method should be preferred, as it correctly notifies init when service is
        actually ready (i.e. pjsua inputs/outputs initialized), so that others can be
        scheduled around that, and primes watchdog timer, detecting if/when app might
        hang due to some bug.
        
        Provided ``paging.service`` file (in the repository, just an ini file) should be
        installed to ``/etc/systemd/system``, and assumes following things:
        
        * PagingServer app should be run as a "paging" user, which exists on the system
          (e.g. in ``/etc/passwd``).
        
        * "paging.py" script, its "entry point" or symlink to it is installed at
          ``/usr/local/bin/paging``.
        
        * Configuration file can be read from one of default paths
          (see above for a list of these).
        
        * Optional python-systemd_ module dependency is installed.
        
        There's also related ``paging-jack-out-all.service`` unit file for starting
        jackd1 and its audio outputs (see "JACK output configuration" section below for
        more info).
        
        With all these correct, service can then be used like this:
        
        * Start/stop/restart service::
        
            % systemctl start paging-jack-out-all
            % systemctl start paging
            % systemctl stop paging
            % systemctl restart paging
        
          Same can be done with related ``paging-jack-out-all`` service (just replace
          "paging" with that name), which should be started/enabled along with
          ``paging`` service.
        
        * Enable service(s) to start on OS boot::
        
            systemctl enable paging-jack-out-all paging
        
          See "JACK output configuration" section below for more info on
          "paging-jack-out-all" service and what it can be replaced with in a
          non-trivial audio setup.
        
        * See if service is running, show last log entries: ``systemctl status paging``
        * Show all logs for service since last OS boot: ``journalctl -ab -u paging``
        
        * Show logs for related jackd service: ``journalctl -ab -u jack@paging``
        
        * Continously show ("tail") all logs in the system: ``journalctl -af``
        
        * Brutally kill service if it hangs on stop/restart:
          ``systemctl kill -s KILL paging``
          (will be done after ~60s by systemd automatically).
        
        See `systemctl(1) manpage`_ for more info on such commands.
        
        If either app itself is installed to another location (not
        ``/usr/local/bin/paging``) or extra command-line parameters for it are required,
        ``ExecStart=`` line can be altered either in installed systemd unit file
        directly, or via ``systemctl edit paging``.
        
        ``systemctl daemon-reload`` should be run for any modifications to
        ``/etc/systemd/system/paging.service`` to take effect.
        
        Similarly, ``User=paging`` line can be altered or overidden to change system uid
        to use for the app.
        
        If python-systemd module is unavailable, following lines should be dropped from
        the ``paging.service``::
        
          Type=notify
          WatchdogSec=...
        
        And ``--systemd`` option removed from ``ExecStart=`` line, so that app would be
        started as a simple non-forking process, which will then be treated correctly by
        systemd without two options above.
        
        
        
        Installation
        ------------
        
        This is a regular package for Python 2.7 (not 3.X), but with some extra
        run-time requirements (see below), which can't be installed from PyPI.
        
        Package itself can be installed at any time using pip_, e.g. via ``pip install
        PagingServer`` (this will try to install stuff to /usr!!!).
        
        Unless you know python packaging though, please look at `pip2014.com`_, `python
        packaging tutorial`_, documentation below for easy installation (from
        packages/repo) on specific systems, or a more detailed step-by-step instructions
        for both python package and other requirements in "README.install.rst" file.
        
        
        Requirements
        ````````````
        
        * `Python 2.7`_ (NOT 3.X).
        
        * PJSUA_ (PJSIP User Agent) and its python bindings.
        
          Can be packaged as "pjsip", "pjsua" or "pjproject" in linux distros.
        
          Python bindings (from the same tarball) can also be packaged separately as
          "python-pjproject" or something like that.
        
          If either of those isn't available, be sure to build and install pjsua AND its
          python bindings manually from the same sources, and NOT e.g. install pjsua
          from package and then build bindings separately.
        
        * JACK_ - both JACK1 (C) and JACK2 (C++) forks should work.
        
          Only tested with JACK1 fork, but as both have same ABI and only interacted
          with via libjack, there should be no difference wrt which one is actually
          running.
        
        * `JACK-Client python module`_
        
        * (optional) ffmpeg_ binary - if audio samples are not wav files (will be
          converted on every startup, if needed).
        
        * (optional) python-systemd_ - only if ``--systemd`` option is used (e.g. with
          shipped .service file).
        
          Developed and shipped separately from main systemd package since v223
          (2015-07-29), likely comes installed with systemd prior to that.
        
          Would probably make sense to install that module from OS package, which should
          be available if systemd is used there as init by default.
        
        * (optional) raven_ python module - for reporting any errors via sentry.
        
        
        Debian Jessie
        `````````````
        
        * Installing everything via debian packages from third-party repository.
        
          Should be the easiest way by far::
        
            % apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3D021F1F4C670809
            % echo 'deb http://paging-server.ddns.net/ jessie main' >/etc/apt/sources.list.d/paging-server.list
            % apt-get update
        
            % apt-get install --no-install-recommends jackd1 alsa-utils
            % apt-get install paging-server
        
            % useradd -r -d /var/empty -s /bin/false -G audio paging
            % install -o root -g paging -m640 -T /usr/share/doc/paging-server/paging.example.conf /etc/paging.conf
        
          Then edit config in ``/etc/paging.conf`` and start and/or enable jackd, its
          bridge to ALSA hardware and server::
        
            % nano /etc/paging.conf
            % systemctl start paging-jack-out-all paging
            % systemctl enable paging-jack-out-all paging
        
          See "Usage" section for more details on how to run the thing.
        
          Packages here are built with `install.debian_jessie.sh`_ script described in
          the next section.
        
        * Building/installing everything on-site with one script.
        
          It's possible to install all required packages, building missing ones where
          necessary by running `install.debian_jessie.sh`_ script from the repository as
          a root user (as it runs apt-get and such)::
        
            % wget https://raw.githubusercontent.com/AccelerateNetworks/PagingServer/master/install.debian_jessie.sh
            % bash install.debian_jessie.sh -x
        
          (running without -x flag will issue a warning message and exit)
        
          It's safe to run the script several times or on a machine where some of the
          requirements (see the list above) are installed already - should skip steps
          that are already done or unnecessary.
        
          Script builds everything into deb packages, stores each in
          ``/var/tmp/PagingServer.debs``, and installs them.
        
          Also creates ``apt-get-installed.list`` file in the same directory, where
          every package name it has passed to apt-get (i.e. packages that it has
          installed via apt-get) is recorded, in case there might be a need to clean
          these up later.
        
          After successful installation, enable/run the service as described in "Usage" section.
        
        * Manual installation.
        
          See detailed description in the `README.install.rst`_ file.
        
        
        Other systems
        `````````````
        
        Follow the steps described in `README.install.rst`_ file, adjusting them for
        your system/distribution where necessary.
        
        
        
        Audio configuration
        -------------------
        
        Overview of the software stack related to audio flow:
        
        * PJSUA picks-up the calls, decoding audio streams from SIP connections.
        
        * PJSUA outputs call audio to via PortAudio_.
        
        * PortAudio can use multiple backends on linux systems, including:
        
          * ALSA_ libs (and straight down to linux kernel)
          * OSS (/dev/dsp*, only supported through emulation layer in modern kernels)
          * JACK sound server
          * PulseAudio sound server
            (with a `somewhat unstable patch`_, see `comment on #3`_ for details)
        
          In this particular implementation, JACK backend is used, as it is necessary to
          later multiplex PJSUA output to multiple destinations and mix-in sounds from
          other sources there.
        
          So PortAudio sends sound stream to JACK.
        
        * JACK serves as a "hub", receiving streams from music players (mpd_ instances),
          klaxon sounds, calls picked-up by PJSUA.
        
          JACK mixes these streams together, muting and connecting/disconnecting some as
          necessary, controlled by the server script ("paging").
        
          End result is N stream(s) corresponding to (N) configured hardware output(s).
        
        * JACK outputs resulting sound stream(s) through ALSA libs (and linux from
          there) to the sound hardware.
        
        
        PagingServer audio configuration
        ````````````````````````````````
        
        Configuration here can be roughly divided into these sections (at the moment):
        
        
        * Sound output settings for PJSUA.
        
          Related configuration options:
        
          * pjsua-device
          * pjsua-conf-port
        
          As PortAudio (used by pjsua) can use one (and only one) of multiple backends
          at a time, and each of these backend can have multiple "ports" in turn,
          ``pjsua-device`` should be configured to use JACK backend "device".
        
          To see all devices that PJSUA and PortAudio detects, run::
        
            % paging --dump-pjsua-devices
        
            Detected sound devices:
              [0] HDA ATI SB: ID 440 Analog (hw:0,0)
              [1] HDA ATI SB: ID 440 Digital (hw:0,3)
              [2] HDA ATI HDMI: 0 (hw:1,3)
              [3] sysdefault
              [4] front
              [5] surround21
              [6] surround40
              ...
              [13] dmix
              [14] default
              [15] system
              [16] PulseAudio JACK Source
        
          (output is truncated, as it also includes misc info for each of these
          devices/ports that PortAudio/PJSUA provides)
        
          This should print a potentially-long list of "playback devices" (PJSUA
          terminology) that can be used for output there, as shown above.
        
          JACK default output (as created by e.g. ``-d dummy`` option to jackd) in the
          example list above is called "system" - same as in JACK, and should be matched
          by default.
        
          If any other JACK-input/PortAudio-output should be used, it can be specified
          either as numeric id (number in square brackets on the left) or regexp (python
          style) to match against name in the list.
        
          To avoid having any confusing non-JACK ports there, PortAudio can be compiled
          with only JACK as a backend.
        
          ``pjsua-conf-port`` option can be used to match one of the "conference ports"
          from ``paging --dump-pjsua-conf-ports`` command output in the same fashion, if
          there will ever be more than one (due to more complex pjsua configuration, for
          example), otherwise it'll work fine with empty default.
        
        
        * JACK daemon startup and control client connection configuration.
        
          Related configuration options:
        
          * jack-autostart
          * jack-server-name
          * jack-client-name
        
          All of these are common JACK client settings, described in jackd(1),
          jackstart(1) manpages, libjack or `jack-client module documentation`_.
        
          With exception for self-explanatory ``jack-autostart`` (enabled by default),
          these options should be irrelevant, unless this script is used with multiple
          JACK instances or clients.
        
        
        * Configuration for any non-call inputs (music, klaxons, etc) for JACK.
        
          Related configuration options:
        
          * klaxon
          * jack-music-client-name
          * jack-music-links
        
          "klaxon" can be a path to any file that has sound in it (that ffmpeg would
          understand), and will be played before each announcement call on all
          "jack-output-ports" (see below), and before that call gets answered.
        
          "jack-music-client-name" should be a regexp to match outputs of music clients,
          that should play stuff in-between announcements, and "jack-music-links" allows
          to control which set(s) of speakers they'll be connected to.
        
          For example, if mpd.conf has something like this::
        
            audio_output {
              type "jack"
              name "jack"
              client_name "mpd.paging:test"
            }
        
          Then configuration like this (these are actually defaults)::
        
            jack-music-client-name = ^mpd\.paging:(.*)$
            jack-music-links = left---left right---right
        
          Will connect output from that player to all speakers matched by
          "jack-output-ports" (all available to JACK by default).
        
          Script can be run with ``--dump-jack-ports`` option to show all JACK ports
          that are currently available - all connected players, speakers, cards and such.
        
          See more detailed description of these options and how they're interpreted in
          `paging.example.conf`_.
        
        
        * List of hardware outputs (ALSA PCMs) to use as JACK final outputs/sinks.
        
          Related configuration options:
        
          * jack-output-ports
        
          Same as with PJSUA outputs/ports above, ``jack-output-ports`` can be
          enumerated via ``paging --dump-jack-ports`` command, and filtered by direct id
          or name regexp, if necessary.
        
          Default is to route PJSUA call to all outputs available in JACK.
        
        
        All settings mentioned here are located in the ``[audio]`` section of the
        configuration file.
        
        See `paging.example.conf`_ for more detailed descriptons.
        
        
        JACK output configuration
        `````````````````````````
        
        This relates to the very last step in the "audio flow" list above, and only
        required if "paging-jack-out-all" service using all ALSA cards suggested in the
        "Installation" section above is not desirable for some reason.
        
        Also, it only applies if JACK1 is used (as suggested in "Installation" section),
        for JACK2 see its official documentation on audio adapters.
        
        By default, when started via systemd unit file from this repo (e.g. ``systemctl
        start jack@paging`` or pulled-in as a dependency for ``paging`` service), or via
        ``jackd -d dummy`` as suggested in "Start/run in the foreground" section above,
        jack does not use any hardware audio outputs.
        
        To add these at any time, install alsa-utils (if not installed already) and use
        ``aplay -L`` command to list audio output hardware available::
        
          % aplay -L | grep -A2 ^default
          default:CARD=I82801AAICH
              Intel 82801AA-ICH, Intel 82801AA-ICH
              Default Audio Device
          --
          default:CARD=Intel
              HDA Intel, ID 22 Analog
              Default Audio Device
        
        Here aplay listed two audio cards, which can be used with JACK1's "alsa_out"
        client as ``hw:CARD=I82801AAICH`` and ``hw:CARD=Intel`` respectively.
        
        To add output through second "HDA Intel" sound card to jack, "alsa_out" client
        (running as daemon) should be started with that card name, e.g. to do it
        manually from console::
        
          % alsa_out -d hw:CARD=Intel &>/dev/null
        
        This will run indefinitely, serving as a bridge between JACK1 "jackd" daemon and
        specified sound hardware outputs.
        
        Keep in mind that "alsa_out" processes must be started with the same uid (user)
        as jackd, and have access to audio hardware (i.e. have "audio" group on most
        distros, if user is not root).
        
        For production use, it'd make sense to start this process for every needed card
        on system boot.
        
        This can be done via ``paging-jack-out-all.service`` unit file from the repo
        (should be installed with "paging-server" package) for all cards::
        
          % systemctl start paging-jack-out-all
          % systemctl enable paging-jack-out-all
        
        Alternatively, to only enable specific cards (with names from ``aplay -L``
        output above), ``paging-jack-out@.service`` unit file can be used instead.
        
        Example for enabling only ``CARD=I82801AAICH``::
        
          % systemctl stop paging-jack-out-all
          % systemctl disable paging-jack-out-all
        
          % card_unit=$(systemd-escape --template paging-jack-out@.service hw:CARD=I82801AAICH)
          % systemctl start $card_unit
          % systemctl enable $card_unit
        
        Note that "systemd-escape" is used to convert whatever raw name from alsa to
        properly-escaped systemd unit instance.
        
        
        
        Misc tips and tricks
        --------------------
        
        Collection of various things related to this project.
        
        
        Pre-convert klaxon sound(s) to wav from any format
        ``````````````````````````````````````````````````
        
        Can be done via ffmpeg_ with::
        
          ffmpeg -y -v 0 -i sample.mp3 -f wav sample.wav
        
        Where it doesn't actually matter which format source "sample.mp3" is in - can be
        mp3, ogg, aac, mpc, mp4 or whatever else ffmpeg supports.
        
        Might help to avoid startup delays due to conversion of these on each run.
        
        If pjsua will be complaining about sample-rate difference between wav file and
        output, e.g. ``-ar 44100`` option can be used (after ``-f wav``) to have any
        sampling rate for the output file.
        
        
        Running JACK on a system where PulseAudio is the main sound server
        ``````````````````````````````````````````````````````````````````
        
        First of all, jackd has to be started manually there, and strictly before
        pulseaudio server.
        
        ``/etc/pulse/default.pa`` should have something like this at the end
        (after default sink - probably alsa - init!)::
        
          load-module module-jack-source source_name=jack_in
          load-module module-loopback source=jack_in
        
        That will create an output from JACK to PulseAudio and from there to whatever
        actually makes sound on the particular system, provided that the loopback stream
        and source in question are not muted and have some non-zero volume set in pulse.
        
        "module-jack-source" has options for picking which jackd to connect to, if isn't
        not "default", "module-loopback" after it creates a stream from that jack source
        to a default sink (which is probably an ALSA sink).
        
        On the JACK side, "PulseAudio JACK Source" port (sink) gets created, and
        anything connected there will make its way to pulseaudio.
        
        
        Running mpd player connected to JACK
        ````````````````````````````````````
        
        Music Player Daemon (mpd_) is a nice player, well-suited for purposes of
        hands-off playing music all day long in-between any kind of announcements.
        
        It also has `a vast number of clients`_, including evertyhing from IR remote
        listeners (via lirc), bluetooth phones, car stereos, to more conventional
        desktop apps and WebUIs.
        
        Example configuration for mpd with JACK output and "client_name" recognized by
        default PagingServer configuration and suitable for playing pretty much
        anything::
        
          log_file "/dev/stdout"
          music_directory "/mnt/music"
        
          # password "super-secret-admin-password@read,add,control,admin"
          # password "password-for-teh-peeple@read,add,control"
        
          input {
            plugin "curl"
          }
        
          audio_output {
            type "jack"
            name "jack"
            client_name "mpd.paging:test"
            autostart "no"
          }
        
        Note that "password" lines are commented-out, which will allow any client to
        connect without any kind of authorization, so it might be a good idea to change
        these if control port is to be exposed to any kind of non-localhost network.
        
        
        Benchmark script (callram.py)
        `````````````````````````````
        
        Description below is from old README.md file pretty much verbatim.
        
        We've tested this script with thousands of calls, it is fairly reliable and
        light on resources. Total CPU use on a Pentium 4 @ 2.8ghz hovered around 0.5%
        with 4MB ram usage. identical figures were observed on a Celeron D @ 2.53Ghz,
        you could probably get away with whatever your operating system requires to run
        in terms of hardware.
        
        To benchmark, you'll need to set up callram.py.
        
        * Setting up callram.py
        
          This setup assumes you have PJSUA installed, if not, go back to Installation
          earlier in this readme and install it.
        
        * Put the files in the right places::
        
            sudo cp callram.py /opt/bin/callram.py
            sudo cp callram.example.conf /etc/callram.conf
        
        * Add your SIP account::
        
            sudo nano /etc/callram.conf
        
          Change the top 3 values to your SIP server, username (usually ext. number) and
          password.
        
          Then fill in both SIP URI: fields (uri= and to=) with the SIP URI of the
          client you'd like to test.
        
          SIP URIs are usually formatted as ``sip:<extension#>@<exampledomain.com>`` in
          most cases.
        
          The Domain may sometimes be an IPv4 or IPv6 address depending on your setup.
        
        * Run::
        
            /usr/bin/python /opt/bin/callram.py
        
        
        Sending error reports to Sentry
        ```````````````````````````````
        
        Sentry_ is a "modern error logging and aggregation platform".
        
        Python raven_ module has to be installed in order for this to work.
        
        If you followed manual installation instructions from README.install.rst, then
        it should be installed into the same virtualenv as the PagingServer itself,
        i.e. from a root shell run::
        
          % su - paging
          % . PagingServer/bin/activate
          % pip install raven
          % exit
        
        Otherwise that module can be installed from an OS package, if available
        (recommended), or via standard python packaging tools (see `python packaging
        tutorial`_).
        
        Then uncomment and/or set "sentry_dsn" option under the ``[server]`` section of
        the configuration file.
        
        It can also be set via ``--sentry-dsn`` command-line option, e.g. in systemd
        unit distributed with the package, to apply on all setups where package is deployed.
        
        
        
        Copyright and License
        ---------------------
        
        | Code and documentation copyright 2015 Accelerate Networks.
        | Code released under the GNU General Public License v2.0.
        | See LICENSE file in the repository for more details.
        | Docs released under Creative Commons.
        | Please don't be a dick about it.
        
        
        
        .. _PJSUA: http://www.pjsip.org/
        .. _JACK: http://jackaudio.org/
        .. _ALSA: http://www.alsa-project.org/main/index.php/Main_Page
        .. _ini format: https://en.wikipedia.org/wiki/INI_file
        .. _paging.example.conf: https://github.com/AccelerateNetworks/PagingServer/blob/master/paging.example.conf
        .. _PortAudio: http://www.portaudio.com/
        .. _somewhat unstable patch: https://build.opensuse.org/package/show/home:illuusio:portaudio/portaudio
        .. _comment on #3: https://github.com/AccelerateNetworks/PagingServer/issues/3#issuecomment-128797116
        .. _jack-client module documentation: https://jackclient-python.readthedocs.org/#jack.Client
        .. _ffmpeg: http://ffmpeg.org/
        .. _systemctl(1) manpage: http://www.freedesktop.org/software/systemd/man/systemctl.html
        .. _mpd: http://musicpd.org/
        .. _a vast number of clients: http://mpd.wikia.com/wiki/Clients
        .. _Sentry: https://getsentry.com/
        .. _pip: http://pip-installer.org/
        .. _pip2014.com: http://pip2014.com/
        .. _python packaging tutorial: https://packaging.python.org/en/latest/installing.html
        .. _Python 2.7: http://python.org/
        .. _JACK-Client python module: https://pypi.python.org/pypi/JACK-Client/
        .. _raven: https://pypi.python.org/pypi/raven/5.5.0
        .. _python-systemd: https://github.com/systemd/python-systemd
        .. _README.install.rst: https://github.com/AccelerateNetworks/PagingServer/blob/master/README.install.rst
        .. _install.debian_jessie.sh: https://github.com/AccelerateNetworks/PagingServer/blob/master/install.debian_jessie.sh
        
Keywords: sip,telephony,phone,paging,announcement,autoanswer,callpipe,klaxon,pj,pjproject,pjsip,pjsua,jack
Platform: UNKNOWN
Classifier: Development Status :: 4 - Beta
Classifier: Environment :: No Input/Output (Daemon)
Classifier: Environment :: Other Environment
Classifier: Intended Audience :: Customer Service
Classifier: Intended Audience :: Telecommunications Industry
Classifier: License :: OSI Approved
Classifier: License :: OSI Approved :: GNU General Public License v2 (GPLv2)
Classifier: Natural Language :: English
Classifier: Operating System :: POSIX
Classifier: Operating System :: POSIX :: Linux
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 2 :: Only
Classifier: Topic :: Communications :: Telephony
Classifier: Topic :: Multimedia :: Sound/Audio
Classifier: Topic :: Multimedia :: Sound/Audio :: Mixers
Classifier: Topic :: Multimedia :: Sound/Audio :: Speech
