FluidLite

FluidLite (c) 2016 Robin Lobel

FluidLite is a very light version of FluidSynth designed to be hardware, platform and external dependency independent. It only uses standard C libraries.

It also adds support for SF3 files (SF2 files compressed with ogg vorbis) and an additional setting to remove the constraint of channel 9 (drums): fluid_settings_setstr(settings, "synth.drums-channel.active", "no"); you can still select bank 128 on any channel to use drum kits.

FluidLite keeps very minimal functionalities (settings and synth), therefore MIDI file reading, realtime MIDI events and audio output must be implemented externally.

Configuration

By default SF3 support is disabled. To enable it use -DENABLE_SF3=YES with cmake.

Alternatively it can be configured to use stb_vorbis to decompress SF3 instead of Xiph's libogg/libvorbis. You can pass -DSTB_VORBIS=YES to cmake to do it.

You can run cmake to configure and build the sources, and also to install the compiled products. Here are some examples

To configure the sources with debug symbols:

$ cmake -S <source-directory> -B <build-directory> -DCMAKE_BUILD_TYPE=Debug

To configure the sources with an install prefix:

$ cmake -S <source-directory> -B <build-directory> -DCMAKE_INSTALL_PREFIX=/usr/local
---
$ cmake -S <source-directory> -B <build-directory> -DCMAKE_INSTALL_PREFIX=${HOME}/FluidLite

To configure the sources with additional dependency search paths:

$ cmake -S <source-directory> -B <build-directory> -DCMAKE_PREFIX_PATH=${HOME}/tests

To build (compile) the sources:

$ cmake --build <build-directory>

To install the compiled products (needs cmake 3.15 or newer):

$ cmake --install <build-directory>

Here is a bash script that you can customize/use on Linux:

#!/bin/bash
CMAKE="${HOME}/Qt/Tools/CMake/bin/cmake"
SRC="${HOME}/Projects/FluidLite"
BLD="${SRC}-build"
${CMAKE} -S ${SRC} -B ${BLD} \
    -DFLUIDLITE_BUILD_STATIC:BOOL="1" \
    -DFLUIDLITE_BUILD_SHARED:BOOL="1" \
    -DENABLE_SF3:BOOL="1" \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCMAKE_SKIP_RPATH:BOOL="0" \
    -DCMAKE_INSTALL_LIBDIR="lib" \
    -DCMAKE_INSTALL_PREFIX=$HOME/FluidLite \
    -DCMAKE_VERBOSE_MAKEFILE:BOOL="1" \
    $*
read -p "Cancel now or pulse <Enter> to build"
${CMAKE} --build $BLD
read -p "Cancel now or pulse <Enter> to install"
${CMAKE} --install $BLD

See also the complete cmake documentation for more information.

Usage

Here is the source code of the example that resides in example/src/main.c

#include <stdlib.h>
#include <stdio.h>

#include "fluidlite.h"

#define SAMPLE_RATE 44100
#define SAMPLE_SIZE sizeof(float)
#define NUM_FRAMES SAMPLE_RATE
#define NUM_CHANNELS 2
#define NUM_SAMPLES (NUM_FRAMES * NUM_CHANNELS)

int main() {
    fluid_settings_t* settings = new_fluid_settings();
    fluid_synth_t* synth = new_fluid_synth(settings);
    fluid_synth_sfload(synth, "soundfont.sf2", 1);

    float* buffer = calloc(SAMPLE_SIZE, NUM_SAMPLES);

    FILE* file = fopen("float32output.pcm", "wb");

    fluid_synth_noteon(synth, 0, 60, 127);
    fluid_synth_write_float(synth, NUM_FRAMES, buffer, 0, NUM_CHANNELS, buffer, 1, NUM_CHANNELS);
    fwrite(buffer, SAMPLE_SIZE, NUM_SAMPLES, file);

    fluid_synth_noteoff(synth, 0, 60);
    fluid_synth_write_float(synth, NUM_FRAMES, buffer, 0, NUM_CHANNELS, buffer, 1, NUM_CHANNELS);
    fwrite(buffer, SAMPLE_SIZE, NUM_SAMPLES, file);

    fclose(file);

    free(buffer);

    delete_fluid_synth(synth);
    delete_fluid_settings(settings);
}

There is also a cmake project file that you may use to build the example, or to model your own projects:

cmake_minimum_required(VERSION 3.1)
project(fluidlite-test LANGUAGES C)

#1. To find an installed fluidlite with pkg-config:
#find_package(PkgConfig REQUIRED)
#pkg_check_modules(fluidlite REQUIRED fluidlite)

#2. To find an installed fluidlite with cmake only:
#find_package(fluidlite REQUIRED)

#3. using a subdirectory (for instance, a git submodule):
add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/FluidLite)
include(${CMAKE_CURRENT_SOURCE_DIR}/FluidLite/aliases.cmake)

add_executable(${PROJECT_NAME}
    src/main.c
)

if(UNIX AND NOT APPLE)
    find_library(MATH_LIB m)
endif()

# if you include 'aliases.cmake' or after find_package(fluidlite),
# you get two targets defined, that you may link directly here:
# 1. 'fluidlite::fluidlite-static' is the static library
# 2. 'fluidlite::fluidlite' is the shared dynamic library
target_link_libraries(${PROJECT_NAME} PRIVATE
    fluidlite::fluidlite-static
    ${MATH_LIB}
)

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