NAME

   Audio::TinySoundFont - Interface to TinySoundFont, a "SoundFont2
   synthesizer library in a single C/C++ file"

SYNOPSIS

     use Audio::TinySoundFont;
     my $tsf = Audio::TinySoundFont->new('soundfont.sf2');
     $tsf->note_on( 'Clarinet', 60, 1.0 );
     my $samples = $tsf->render( seconds => 5 );
     my $preset = $tsf->preset('Clarinet');
     $tsf->note_off( $preset, 60 );
     $samples .= $tsf->render( seconds => 5 );

     # Using the Preset object
     my $preset = $tsf->preset('Clarinet');
     my $samples = $preset->render(
       seconds => 5,
       note => 60,
       vel => 0.7,
       volume => .3,
     );

     # Using the Builder object
     my $builder = $tsf->new_builder(
       [
         {
           preset => 'Clarinet',
           note   => 59,
           at     => 0,
           for    => 2,
         },
       ]
     );
     $builder->add(
       [
         {
           preset     => $preset,
           note       => 60,
           at         => 44100,
           for        => 44100 * 2,
           in_seconds => 0,
         },
       ]
     );
     my $samples = $builder->render;

DESCRIPTION

   Audio::TinySoundFont is a wrapper around TinySoundFont
   <https://github.com/schellingb/TinySoundFont>, a "SoundFont2
   synthesizer library in a single C/C++ file". This allows you to load a
   SoundFont file and synthesize samples from it.

CONSTRUCTOR

new

     my $tsf = Audio::TinySoundFont->new($soundfont_file, %attributes)

   Construct a new Audio::TinySoundFont object using the provided
   $soundfont_file file. It can be a filename, a file handle, or a string
   reference to the contents of a SoundFont.

 Attributes

   volume

     Set the initial, global volume. This is a floating point number
     between 0.0 and 1.0. The higher the number, the louder the output
     samples.

METHODS

volume

     my $volume = $tsf->volume;
     $tsf->volume( 0.5 );

   Get or set the current global volume. This is a floating point number
   between 0.0 and 1.0. The higher the number, the louder the output
   samples.

preset_count

     my $count = $tsf->preset_count;

   The number of presets available in the SoundFont.

presets

     my %presets = %{ $tsf->presets }

   A HashRef of all of the presets in the SoundFont. The key is the name
   of the preset and the value is the Audio::TinySoundFont::Preset object
   for that preset.

preset

     my $preset = $tsf->preset('Clarinet');

   Get a Audio::TinySoundFont::Preset object by name. This will croak if
   the preset name is not found.

preset_index

     my $preset = $tsf->preset_index($index);

   Get an Audio::TinySoundFont::Preset object by index in the SoundFont.
   This will croak if the index is out of range. Note, this will return a
   different object than "preset" will, which will return the object from
   presets.

SAMPLE_RATE

     my $sample_rate = $tsf->SAMPLE_RATE

   Returns the sample rate that TinySoundFont is operating on, expressed
   as hertz or samples per second. This is currently static and is 44_100;

new_builder

     my $builder = $tsf->new_builder

   Create a new Audio::TinySoundFont::Builder object. This can be used to
   generate a single sample from a script of what notes to play when.

active_voices

     my $count = $tsf->active_voices;

   Returns the number of currently active voices that TinySoundFont is
   rendering. Generally speaking, each "note_on" will make one or more
   voices active.

is_active

     my $bool = $tsf->is_active

   Returns if TinySoundFont currently has active voices and will output
   audio during render.

note_on

     $tsf->note_on($preset, $note, $velocity);

   Turns a note on for a Preset. $preset can either be a
   Audio::TinySoundFont::Preset object or the name of a Preset. Both $note
   and $velocity are optional. $note is a MIDI note between 0 and 127,
   with 60 being middle C and the default if it is not given. $velocity is
   a floating point number between 0.0 and 1.0 with the default being 0.5.

note_off

     $tsf->note_off($preset, $note);

   Turns a note off for a Preset. $preset can either be a
   Audio::TinySoundFont::Preset object or the name of a Preset. $note is
   optional and is the same MIDI note given on "note_on". The default is
   60. This will not immediately stop a note from playing, it will begin
   the note's release phase.

render

     my $samples = $tsf->render( seconds => 5 );
     my $samples = $tsf->render( samples => 44_100 );

   Returns a string of 16-bit, little endian sound samples using
   TinySoundFont of the specified length. The result can be unpacked using
   unpack("s<*") or you can call "render_unpack" function to get an array
   instead. This will return the exact number of samples requested;
   calling "render" 5 times at 1 second each is identical to calling
   "render" once for 5 seconds.

   seconds

     This sets how many samples to generate in terms of seconds. The
     default is 1 second. If both "seconds" and "samples" are given,
     seconds will be used.

   samples

     This sets how many samples to generate in terms of seconds. The
     default is "SAMPLE_RATE". If both "seconds" and "samples" are given,
     seconds will be used.

render_unpack

     my @samples = $tsf->render_unpack(%options);

   Returns an array of of 16-bit sound samples using TinySoundFont. All of
   the options are identical to "render".

db_to_vol

     my $volume = $tsf->db_to_vol(-10);

   Convert from dB to a floating point volume. The dB is expressed as a
   number between -100 and 0, and will map logarithmically to 0.0 to 1.0.

Terminology

   The SoundFount terminology can get confusing at times, so I've included
   a quick reference to help make sense of these.

   Terminology used directly in Audio::TinySoundFont

     To be able to use Audio::TinySoundFont, you will need to know a
     couple simple terms. They are likely easy to infer, but they are here
     so that their meaning is explicit instead of implicit.

     SoundFont

       Sometimes referred to as SoundFont2, this is a file format designed
       to store and exchange synthesizer information. This includes the
       audio samples to create the audio, how to generate and modify the
       samples to sound as expected, and generally how to produce audio
       that the SoundFont creator wanted.

     Preset

       A Preset is the largest usable building block in a SoundFont and
       generally represents a single instrument. If you've ever sat down
       to an electric keyboard and selected "Electric Guitar", "Violin" or
       "Synth", you are selecting the equivalent of a SoundFont preset.

   Terminology used when talking about SoundFonts

     Reading the entire SoundFont2 specification can be daunting. In
     short, it is a RIFF
     <https://en.wikipedia.org/wiki/Resource_Interchange_File_Format> file
     that primarily holds 9 types of data, or "sub-chunks". All of this
     data ultimately describes a Preset that is used in constructing audio
     by TinySoundFont. It is not required to understand these to use
     Audio::TinySoundFont and will not be used in the rest of the
     documentation.

     PHDR/PBAG (Preset)

       These are the two sections that describe a Preset. A PHDR record
       describes a Preset like the name, preset number and bank number.
       The PBAG contains what are called Preset Zones which lists the
       generators and modulators to use for a specific preset given a
       range of notes and velocity. One of those generators is which
       Instrument to use, which has its own set of generators and
       modulators.

     INST/IBAT (Instrument)

       An instrument is very similar in structure to a Preset, but
       provides a layer of indirection between the raw samples and the
       presets. A single Instrument can be used in multiple Presets, for
       instance a single Guitar Instrument can be used for a regular
       guitar as well one with extra reverb. These two sections serve the
       same function as the Preset sections. A INST describes an
       Instrument and the PBAG contains Instrument Zones which lists the
       generators and modulators to use for a given range of notes and
       velocities. One of the generators is the sample to use for this
       Instrument.

     PGEN

     PMOD

     IGEN

     IMOD

       Each preset and instrument is composed of one or more generators
       and modulators. The PGEN and PMOD sections are used to construct
       the Preset Zones, likewise the IGEN and IMOD sections are used to
       construct Instrument Zones. They describe a single aspect of how to
       construct the audio samples, for instance adding a low-pass filter
       or reverb. Some are only available for a preset, like what
       Instrument to use, and some are only available to Instruments like
       what Sample to use.

       Note: TinySoundFont does not currently process modulators.

     SHDR (Samples)

       This section describes the actual audio samples to be used,
       including a name, the length, the original pitch, pitch correction,
       and looping configuration. The actual audio samples are stored in a
       different RIFF chunk, but this contains the references into that
       chunk about where to find the data.

AUTHOR

   Jon Gentle <[email protected]>

COPYRIGHT

   Copyright 2020- Jon Gentle

LICENSE

   This is free software. You may redistribute copies of it under the
   terms of the Artistic License 2 as published by The Perl Foundation.

SEE ALSO

   Audio::TinySoundFont::Preset, Audio::TinySoundFont::Builder,
   TinySoundFont <https://github.com/schellingb/TinySoundFont>