fluidsynth/doc/usage/loading_soundfonts.txt

/*!

\page LoadingSoundfonts Loading and managing SoundFonts

Before any sound can be produced, the synthesizer needs a SoundFont.

SoundFonts are loaded with the fluid_synth_sfload() function. The function
takes the path to a SoundFont file and a boolean to indicate whether the
presets of the MIDI channels should be updated after the SoundFont is loaded.
When the boolean value is TRUE, all MIDI channel bank and program numbers
will be refreshed, which may cause new instruments to be selected from the
newly loaded SoundFont.

The synthesizer can load any number of SoundFonts. The loaded SoundFonts are
treated as a stack, where each new loaded SoundFont is placed at the top of
the stack. When selecting presets by bank and program numbers, SoundFonts are
searched beginning at the top of the stack. In the case where there are
presets in different SoundFonts with identical bank and program numbers, the
preset from the most recently loaded SoundFont is used. The
fluid_synth_program_select() can be used for unambiguously selecting a preset
or bank offsets could be applied to each SoundFont with
fluid_synth_set_bank_offset(), to try and ensure that each preset has unique
bank and program numbers.

The fluid_synth_sfload() function returns the unique identifier of the loaded
SoundFont, or -1 in case of an error. This identifier is used in subsequent
management functions: fluid_synth_sfunload() removes the SoundFont,
fluid_synth_sfreload() reloads the SoundFont. When a SoundFont is reloaded,
it retains it's ID and position on the SoundFont stack.

Additional API functions are provided to get the number of loaded SoundFonts
and to get a pointer to the SoundFont. 

*/