himd-js

JS library for accessing HiMD Minidisc devices

This is a brand new library for reading and writing HiMD media. Unlike linux-minidisc, himd-js supports writing ATRAC3, ATRAC3+ and PCM audio as well as MP3.

For now, it is impossible to use this library as a standalone application - there's no CLI available.

How to incorporate it into your project?

The library has two modes of operation:

1 - FileSystem access only

In this mode, it's only possible to read and write tracks' metadata (titles, track play order, etc.), upload MP3s and download the audio.

It is not possible to upload ATRAC3/3+/PCM with this mode.

Example:

async function example(){
    // When using Node.JS:
    const fs = new NativeHiMDFilesystem("/path/to/HiMD/root");
    // When using Chrome (FileSystemAccess API):
    const fs = await FSAHiMDFilesystem.init();

    const himd = await HiMD.init(fs);

    // Use the HiMD handle
    renameDisc(himd, "Example disc!");

    // Upload an MP3 file
    const stream = await himd.openWriteStream();
    const title = {
        title: "Example",
        album: "Test",
        artist: "Foobar",
    };
    await uploadMP3Track(himd, stream, mp3DataArrayBuffer, title, console.log);
    
    // Do not forget to flush the changes!
    await himd.flush();
}

2 - Direct mode (USB Mass Storage Controller mode)

Because this mode takes full control over the HiMD device, and can issue SCSI commands directly to it, it's possible to upload ATRAC3/3+/PCM audio

All the examples from mode 1 which utilize the HiMD object still work.

Example:

async function example(){
    // There are two ways to get the WebUSB handle for a HiMD device
    // 1. Under Chrome - use the `netmd-exploits` library with the 'HiMDUSBClassOverride' exploit
    // 2. Under Node.JS - use the legacy API of the `usb` library, then invoke `.detachKernelDriver()` on the interface object
    const fs = new UMSCHiMDFilesystem(webusbHiMDSCSIHandle);
    await fs.init();
    const driver = fs.driver;

    const himd = await HiMD.init(fs);

    // Upload a MAC-protected audio track (AT3/3+/PCM)
    const title = {
        title: "Example",
        album: "Test",
        artist: "Foobar",
    };

    // Create a WriteStream
    const stream = await himd.openWriteStream();

    // Create a new session
    const session = new UMSCHiMDSession(driver, himd);
    await session.performAuthentication();

    // Example for ATRAC3 at 66kbps (LP4 on normal Minidisc)
    const codecInfo = generateCodecInfo("AT3", HiMDKBPSToFrameSize.atrac3[66]);
    await uploadMacDependent(himd, session, stream, atrac3RawArrayBuffer, codecInfo, title, console.log);
    
    // Finalize the session
    await session.finalizeSession();
}

Credits

• Thank you to M Karcher over at the MiniDisc.wiki Discord server for explaining how the DRM implemented by HiMD devices works. This wouldn't be possible without his incredible help.
• The linux-minidisc documentation on HiMD SCSI commands and file formats (1, 2, 3, 4)