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Converting between various file formats

This guide demonstrates how to convert various file formats using spessasynth_core. Whether you're working with SoundFont files (SF2, SF3), Downloadable Sounds (DLS), or MIDI-related formats (RMI, MIDI), these examples will help you perform conversions quickly and efficiently.

Important

The input file binary is named input and the output binary file is named output in the examples.

SF2 To SF3

Note

This example uses soundfont3 compression. Make sure you've read this

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const sfont = SoundBankLoader.fromArrayBuffer(input);
await sfont.setSampleFormat({
    format: "compressed",
    compressionFunction: SampleEncodingFunction // make sure to get the function for compression
});
const output = sfont.writeSF2();

SF3 To SF2

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const sfont = SoundBankLoader.fromArrayBuffer(input);
await sfont.setSampleFormat({
    format: "pcm"
});
const output = sfont.writeSF2();

DLS to SF2

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const sfont = SoundBankLoader.fromArrayBuffer(input);
const output = sfont.writeSF2();

SF2 To DLS

Make sure to read about the DLS conversion problem

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const sfont = SoundBankLoader.fromArrayBuffer(input);
const output = sfont.writeDLS();

RMI To MIDI

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const rmid = BasicMIDI.fromArrayBuffer(input);
const output = rmid.writeMIDI();

RMI To SF2/SF3

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const rmid = BasicMIDI.fromArrayBuffer(input);
const sfont = SoundBankLoader.fromArrayBuffer(rmid.embeddedSoundBank);
const output = sfont.writeSF2();

SF2/DLS + MIDI To RMI

This uses two inputs, input1 for MIDI and input2 for the sound bank.

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const mid = BasicMIDI.fromArrayBuffer(input1);
const sfont = SoundBankLoader.fromArrayBuffer(input2);
// compress this if you want
const sfontBinary = sfont.writeSF2();
const output = mid.writeRMIDI(
    sfontBinary,
    sfont,
    0, // bank offset: adjust this if necessary
    "utf-8", // encoding: utf-8 recommended
    {
        // all the values below are examples, showing how to copy MIDI data to the RMI file
        name: mid.getName(),
        copyright: mid.getExtraMetadata(),
        engineer: sfont.soundBankInfo.engineer
    },
    true // adjust program changes: recommended for self-contained files
);

DLS RMI To SF2 RMI

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const dlsRMID = BasicMIDI.fromArrayBuffer(input);
const sfont = SoundBankLoader.fromArrayBuffer(dlsRMID.embeddedSoundBank);
const sfontBinary = sfont.writeSF2();
const output = dlsRMID.writeRMIDI(
    sfontBinary,
    sfont,
    dlsRMID.bankOffset, // bank offset gets detected for DLS rmi
    "utf-8", // encoding: utf-8 recommended
    {
        // here we try to extract the metadata from the file, then fall back to embedded MIDI
        name: dlsRMID.getName(),
        copyright: dlsRMID.rmidiInfo.copyright || dlsRMID.getExtraMetadata(),
        engineer: sfont.soundBankInfo.engineer,
        artist: dlsRMID.getRMIDInfo("artist"),
        album: dlsRMID.getRMIDInfo("album"),
        genre: dlsRMID.getRMIDInfo("genre"),
        comment: dlsRMID.getRMIDInfo("comment"),
        // either use the embedded one or today
        creationDate: dlsRMID.getRMIDInfo("creationDate") ?? new Date()
    },
    false // adjust program changes: I recommend false for that one
);