webmscore

webmscore

MuseScore's libmscore (the core library) in WebAssembly!

Features

• Parse mscz file data
• Get score metadata
• Export part score
• Generate music sheets in SVG/PNG/PDF format
• Generate MIDI
• Generate audio files in WAV, OGG, MP3, or FLAC format
• Synthesize raw audio frames, can be used in the Web Audio API
• Export as MusicXML compressed/uncompressed
• Generate position information of measures or segments on the generated sheets
• Run inside a Web Worker thread

Installation

The package is available on npm: https://www.npmjs.com/package/webmscore

npm i webmscore

Use webmscore

Load in browsers

<!-- using a CDN -->
<script src="https://cdn.jsdelivr.net/npm/webmscore/webmscore.js"></script>
<script>
    WebMscore.ready.then(async () => {
        const score = await WebMscore.load('mscz', msczdata)
    })
</script>

For latest browsers which support ES Modules

import WebMscore from 'https://cdn.jsdelivr.net/npm/webmscore/webmscore.mjs'

Run in Node.js directly

Minimum version: v8.9.0 with ES Modules support

The --experimental-modules flag is required for Node.js versions under 14,
Also require "type": "module" in package.json

import WebMscore from 'webmscore'
WebMscore.ready.then(async () => {
    const score = await WebMscore.load('mscz', msczdata)
})

Use a JavaScript bundler

(TBD)

Load extra fonts

If your score sheet contains characters out of the range of the bundled FreeFont, those characters will be shown as tofu characters (□ or �) in SVG/PNG/PDF files. Loading extra fonts is required.

webmscore can load any font format supported by FreeType.

const score = await WebMscore.load('mscz', msczdata, [...arrOfFontData])

CJK fonts are no longer bundled inside webmscore since v0.6.0

Load soundfont files

Loading a soudfont (sf2/sf3) file is required before generating/synthesizing audio.

await score.setSoundFont(soudfontData)

Soudfonts can be found on musescore.org website.

Example: (FluidR3Mono_GM.sf3)

const soudfontData = new Uint8Array(
    await (
        await fetch('https://cdn.jsdelivr.net/gh/musescore/MuseScore@2.1/share/sound/FluidR3Mono_GM.sf3')
    ).arrayBuffer()
)

Boost Mode

Sometimes you only want to process a bunch of score metadata, so drawing sheet images internally is a waste of time and system resource.

You can enable the Boost Mode by setting the doLayout parameter in WebMscore.load to false.

Example:

const score = await WebMscore.load('mscz', msczdata, [], false)
const metadata = await score.metadata()
score.destroy()

webmscore's Boost Mode is about 3x faster than the batch converter feature (-j) of the musescore software, according to the benchmark result.

WebAssembly vs native C++ program!

Compiling

1. Install essential tools like make, cmake, llvm, etc.

2. Install emscripten v2.0.6 using emsdk https://emscripten.org/docs/getting_started/downloads.html

3. Get and compile Qt5 for WebAssembly

CPUS=$(getconf _NPROCESSORS_ONLN 2>/dev/null || getconf NPROCESSORS_ONLN 2>/dev/null || 8)

QT_PATH=/usr/qt515
# If you want to use other directory, make sure you changed `PREFIX_PATH` to your Qt5WASM installation dir in the Makefile

git clone git://code.qt.io/qt/qt5.git --depth=1 -b 5.15.0 $QT_PATH
# or
# download and extract qt-everywhere 5.15.0 (https://download.qt.io/official_releases/qt/5.15/5.15.0/single/)

cd $QT_PATH
./configure -xplatform wasm-emscripten -nomake examples -prefix $PWD/qtbase
make -j$CPUS

# exclude unused Qt5Gui plugins
sed -i -E "s/\s(\S+?Qt5Gui_)\*(Plugin)?(.*)\)/ \1QWasmIntegrationPlugin\3 \1QJpegPlugin\3)/" $QT_PATH/qtbase/lib/cmake/Qt5Gui/Qt5GuiConfig.cmake

# patch emcc.py to emit separate .mem files regardless of MEM_INIT_METHOD settings (MEM_INIT_METHOD won't work with wasm)
sed -i -r "s/(shared.Settings.MEM_INIT_IN_WASM = )True/\1False/" "$(which emcc).py"

1. Checkout submodules

git submodule init
git submodule update

1. Compile webmscore

make release

Build artifacts are in the web-public directory

Browser Support

All modern browsers which support WebAssembly and Async Functions

Name	Minimum Version
Chrome	57
Firefox	53, 52 (non-ESR)
Edge	16 (Fall Creators Update)
Safari	11
IE	NO!
Other browsers	I don't know!

Only tested on the latest version of Chrome and Firefox.

Examples

see files in the web-example directory

cd ./web-example
npm i
npm start  # Node.js example
npm run start:browser  # browser example

Debugging

See How to look up function names in the .symbols file?

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webmscore is part of the LibreScore project.