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

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

DLS to SF2

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

SF2 To DLS

Make sure to read about the DLS conversion problem

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

RMI To MIDI

const rmid = BasicMIDI.fromArrayBuffer(input);
const output = await rmid.writeSF2();

RMI To SF2/SF3

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

SF2/DLS + MIDI To RMI

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

const mid = BasicMIDI.fromArrayBuffer(input1);
const sfont = SoundBankLoader.fromArrayBuffer(input2);
// compress this if you want
const sfontBinary = await 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

```ts
const dlsRMID = BasicMIDI.fromArrayBuffer(input);
const sfont = SoundBankLoader.fromArrayBuffer(dlsRMID.embeddedSoundBank);
const sfontBinary = await 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
);