NAME
    Audio::Ecasound - Perl binding to the ecasound sampler, recorder,
    fx-processor

SYNOPSIS
    One function interface:

        use Audio::Ecasound qw(:simple);

        eci("cs-add play_chainsetup");
        eci("c-add 1st_chain");
        eci("-i:some_file.wav");
        eci("-o:/dev/dsp");
        # multiple \n separated commands
        eci("cop-add -efl:100
             # with comments
             cop-select 1
             copp-select 1
             cs-connect");
        eci("start");
        my $cutoff_inc = 500.0;
        while (1) {
            sleep(1);
            last if eci("engine-status") ne "running";

            my $curpos = eci("get-position");
            last if $curpos > 15;

            my $next_cutoff = $cutoff_inc + eci("copp-get");
            # Optional float argument
            eci("copp-set", $next_cutoff);
        }
        eci("stop");
        eci("cs-disconnect");
        print "Chain operator status: ", eci("cop-status");

    Object Interface

      use Audio::Ecasound;

      my $e = new Audio::Ecasound;
      $e->on_error('');
      $e->eci("cs-add play_chainsetup");
      # etc.

    Vanilla Ecasound Control Interface (See Ecasound's Programmer Guide):

      use Audio::Ecasound qw(:std);

      command("copp-get");
      $precise_float = last_float() / 2;
      command_float_arg("copp-set", $precise_float);
      warn last_error() if error();

    IAM Interface, pretend interactive mode commands are functions.

      use Audio::Ecasound qw(:iam :simple);

      # iam commands as functions with s/-/_/g
      my $val = copp_get;
      copp_set $val+0.1; # floats are stringified so beware
      eci("-i /dev/dsp"); # not all commands are exported

DESCRIPTION
    Audio::Ecasound provides perl bindings to the ecasound control interface
    of the ecasound program. You can use perl to automate or interact with
    ecasound so you don't have to turn you back on the adoring masses packed
    into Wembly Stadium.

    Ecasound is a software package designed for multitrack audio processing.
    It can be used for audio playback, recording, format conversions,
    effects processing, mixing, as a LADSPA plugin host and JACK node.
    Version >= 2.2.X must be installed to use this package. "SEE ALSO" for
    more info.

INSTALLATION
     perl Makefile.PL

    If your perl wasn't built with -Dusethreads or -D_REENTRANT you will be
    prompted whether to continue with the install. It's in your hands... See
    "THREADING NOTE"

     make
     make test
     make install

THREADING NOTE
    The ecasoundc library uses pthreads so will may only work if your perl
    was compiled with threading enabled, check with:

     % perl -V:usethreads

    You are welcome to try using the module with non-threaded perls (perhaps
    -D_REENTRANT alone would work) it have worked for some.

EXPORT
    *   Nothing by default as when going OO.

    *   :simple gives eci() which does most everything, also errmsg and
        on_error. Or you could just import 'eci' and call the others
        "Audio::Ecasound::errmsg()"

    *   :iam imports many iam commands so that you can use them as perl
        functions. Basically everything listed by ecasound's 'int-cmd-list'
        except the single letter commands and hyphens are replaced by
        underscores. The list is produced at run-time and returned by
        Audio::Ecasound::get_iam_cmds(). See "IAM COMMANDS";

    *   :std to import the full ecasound control interface detailed in the
        Ecasound Programmer's Guide.

    *   :raw and raw_r, C functions with minimal wrapping, _r ones are
        reentrant and must be passed the object returned by eci_init_r(). I
        don't know why you would use these, presumably you do. These options
        may be removed in future.

METHODS AND FUNCTIONS
    The procedural and OO interfaces use the same functions, the differences
    are that when called on an Audio::Ecasound object the reentrant C
    versions are used so you can have multiple independent engine (with
    independent options).

    new()
      Constructor for Audio::Ecasound objects, inherits the on_error and
      other options from the current package settings (defaults if
      untouched).

    eci('ecasound command string', [$float_argument])
      Sends commands to the Ecasound engine. A single command may be called
      with an optional float argument (to avoid precision loss).
      Alternatively, multiple commands may be given separated by newlines
      (with "#" starting a comment).

      If called in non-void context the result of the last command is
      returned, it may be an integer, float, string (ie. scalar) or a list
      of strings. Which will depend on the ecasound command, see
      ecasound-iam for each function's return value.

      If there is an error the action given to on_error will be taken. See
      on_error below for return value caveats when on_error = ''. Error
      processing is performed for each command in a multiline command.

    on_error('die')
      Set the action to be taken when an error occurs from and "eci"
      command, may be 'die', 'warn', '', 'confess', ... (default is 'warn').

      When '' is selected "return;" is used for an error, that is undef or
      (). To disamibiguate eci will return '' or ('') for no return value
      and no string list respectively.

    errmsg()
      The last error message from an "eci" command. It is not reset so clear
      it yourself if required "errmsg('')". This shouldn't be necessary as
      you can use "defined" or on_error to find out when errors occur.

    The remainder of the functions/methods are the standard Ecasound Control
    Interface methods but they come in three flavours. The bare function
    name may be called with or without an object:

      use Audio::Ecasound ':simple':
      command($cmd);
      # or
      my $e = new Audio::Ecasound;
      $e = command($cmd);

    The other two flavours are low-level, reentrant and non-reentrant. These
    are thinly wrapped C functions better documented in the ECI document
    with the ecasound distribution. Just add 'eci_' to the names below for
    the non-reentrant version and then add a '_r' to the end for the
    reentrant version. The reentrant version takes an extra first argument,
    the object returned by eci_init_r() which must be destroyed with
    eci_cleanup_r().

    command($cmd_string)
    eci_command_float_arg($cmd_string, $float_arg)
    $bool = eci_error()
    $err_str = eci_last_error()
    $float = eci_last_float()
    $int = eci_last_integer()
    $lint = eci_last_long_integer()
    $str = eci_last_string()
    $n = eci_last_string_list_count()
    $str_n = eci_last_string_list_item($n)
    $type_str = eci_last_type() 's' 'S' 'i' 'li' 'f' ''

IAM COMMANDS
    When the :iam tag is imported most of the commands in ecasounds
    interactive mode become perl functions. The '-'s become '_'s to become
    valid perl names ('cop-get' is cop_get, etc.) The list is printed with:

      use Audio::Ecasound qw(:iam :simple);
      print join ' ', Audio::Ecasound::get_iam_cmds();

    The arguments joined together as a string and then sent to ecasound.
    This means that float precision is lost, unlike with the two argument
    "eci" so use it. Also use "eci" for command-line style commands like
    "eci "-i /dev/dsp"". But most other things you can just use the iam
    command itself (s/-/_/g):

      use Audio::Ecasound qw(:iam :simple);
      ... # setup stuff
      print status;
      start;
      $v = copp_get;
      copp_set $v + 1.2;

    I would never encourage anyone to use "no strict 'subs';" but with :iam
    you may enjoy a little less discipline.

    See the iam_int.pl example file in the eg directory.

EXAMPLES
    See the "eg/" subdirectory.

TROUBLESHOOTING
    The ecasound command 'debug' could be useful, add "eci "debug 63"" to
    the top of your program. The argument is various bits OR'd and controls
    the amount and type of debugging information, see the ecasound
    documentation of source or just try your favorite powers of two.

FILES AND ENVIRONMENT
    The libecasoundc library now uses the environment variable "ECASOUND" to
    find the ecasound executable. If it is not set then the libarary will
    print a warning. To suppress it, simply set the ECASOUND variable: eg.
    export ECASOUND=ecasound

    The ecasound library will still process ~/.ecasoundrc and other setup
    files for default values. See the library documentation.

AUTHOR
    Copyright (C) 2001, Brad Bowman <eci-perl@bereft.net>
    
LICENSE
    This module is free software.  You can redistribute it and/or
    modify it under the terms of the Artistic License 2.0.
    
    This program is distributed in the hope that it will be useful,
    but without any warranty; without even the implied warranty of
    merchantability or fitness for a particular purpose.

SEE ALSO
    The Ecasound Programmer's Guide and ECI doc, ecasound, ecasound-iam
    http://eca.cx/, http://www.ladspa.org/

    The internals of libecasoundc have been rebuilt and now interact with a
    running ecasound via a socket using a protocol defined in the
    Programmer's Guide. The C library is now just a compatibility layer and
    the Python version now talks directly to the socket. It would be
    straight forward to write an equivalent Perl version should the need
    arise.