What is libmsp?

A small linux shared library which plays music files. Written in C.

Features

• Depends only on libc (2.39+). If you have something equal or more modern than Ubuntu 24 it should just work.
• Supports the most popular music formats (mp3, flac, m4a, wav, aac, ogg) with different codecs in them.
• Built on top of ffmpeg and SDL3. I'm not that crazy (yet) to write so much code by myself.

How it works / how to use

Public library interface is defined and documented in libmsp.h header.

libmsp uses two threads:

1. Main thread to push user commands to the playback thread with one exception: msp_get_metadata() works in the main thread. All other functions are expected to return instantly and won't block your app.
2. Playback thread listens commands in a loop, and also does dirty decoding work if it requested to play something.
   It does not decode many frames ahead and does not waste much CPU.

Usage general steps are:

1. Initialize playback context.
2. Use functions to play, pause, etc.
3. Deinitialize to free inner resources.

For usage example see testapp.c (WIP)

The minimal code sample:

#include "../src/libmsp.h"
#include <unistd.h>

int main() {
    playback_context_t *player = msp_init();
    msp_play(player, "music.mp3");
    sleep(10);  // without sleep msp_play() instantly returns and you won't hear anything
    msp_deinit(player);
    return 0;
}

How to build

Prerequisites

• linux (for local build, container build should work on any platform). I didn't test it anywhere else.
• cmake
• gcc
• just
• podman

Build

First of all, you can check just --list and see full list of available recipes.

The build itself consists of two parts: 1. ffmpeg static build 2. every other stuff build. The 1st part historically
builds only in a container, because I wanted to get reproducible builds while figuring out what demuxers and codecs I can and what I can't turn off. So for now even for a local build you need podman.
The 2nd part - library itself - could be built in a container or locally.

Full build in podman

Ready for distribution release build
just podman-build
And see ./dist folder for .so

Local debug build

Builds ffmpeg-static in podman, copies it to the host, and builds libmsp locally. Also builds testapp binary.
just build

Why it exists?

1. Because I can :)
2. I have a pet-project music player with Godot UI (because why not), and it needs a good playback backend.
   I tried LibVLC, and it is great, but it has a bunch of dependencies, basically it requires whole vlc package to work, and C# wrapper nuget package for LibVLC does not include any native libs at all. And I want a self-contained binary.
   Also, Godot does not include native libs into distribution by default, so you have to deal with LD_LIBRARY_PATH hacks etc.
   So, I decided to build own minimalistic library and ship it in nuget package. C# wrapper is here.
3. This is a great opportunity for me to code something in a system language.

What MSP stands for?

It stands for "My Stupid Player"