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134 lines
2.7 KiB
Markdown
134 lines
2.7 KiB
Markdown
# synth-js
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Command-line utility and Node module for generating raw audio data from MIDI files.
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## Installation
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### Command-line utility:
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```bash
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$ npm link synth-js
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```
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### Node module:
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```bash
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$ npm install --save synth-js
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```
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### JavaScript:
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```html
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<script src="synth.min.js"></script>
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```
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After including the file from `dst/synth.min.js`, the global variable `synth` will be initialized.
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## Usage
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### Command-line utility:
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```bash
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# assuming song.mid in cwd
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$ synth -i song
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# now song.wav contains raw audio data for song.mid
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```
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### Node module:
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```js
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const synth = require('synth-js');
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const fs = require('fs');
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let midBuffer = fs.readFileSync('song.mid');
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// convert midi buffer to wav buffer
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let wavBuffer = synth.midiToWav(midiBuffer).toBuffer();
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fs.writeFileSync('song.wav', wavBuffer, {encoding: 'binary'});
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```
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### JavaScript:
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```html
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<style>
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#wav:after {
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content: " " attr(download);
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}
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#wav:not([href]) {
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display: none;
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}
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</style>
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<input type="file" id="midi" accept="audio/midi">
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<a id="wav">Download</a>
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<script>
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var audio;
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var input = document.getElementById('midi');
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var anchor = document.getElementById('wav');
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input.addEventListener('change', function change() {
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// clean up previous song, if any
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if (anchor.hasAttribute('href')) {
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URL.revokeObjectURL(anchor.href);
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anchor.removeAttribute('href');
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if (audio && !audio.paused) {
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audio.pause();
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}
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}
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// check if file exists
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if (input.files.length > 0) {
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var reader = new FileReader();
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var midName = input.files[0].name;
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// replace file extension with .wav
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var wavName = midName.replace(/\..+?$/, '.wav');
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// set callback for array buffer
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reader.addEventListener('load', function load(event) {
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// convert midi arraybuffer to wav blob
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var wav = synth.midiToWav(event.target.result).toBlob();
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// create a temporary URL to the wav file
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var src = URL.createObjectURL(wav);
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audio = new Audio(src);
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audio.play();
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anchor.setAttribute('href', src);
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});
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// read the file as an array buffer
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reader.readAsArrayBuffer(input.files[0]);
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// set the name of the wav file
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anchor.setAttribute('download', wavName);
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}
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});
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</script>
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```
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See the demo [here][browser-demo].
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## FAQ
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### Where can I find documentation?
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Currently, documentation only exists for the command-line utility.
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To access it, use `man`:
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```bash
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$ man synth
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```
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For Node or JavaScript, refer to the `src/` directory for accessible APIs:
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* `synth.WAV()`
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* `synth.MIDIStream()`
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* `synth.midiToWav()`
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## License
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Available under the MIT License
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[browser-demo]: https://jsfiddle.net/patrob10114/o5r1adyz/show/
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