PlayAlong
Be the missing part of any song.
Paste a YouTube link or drop in a song. PlayAlong takes it apart into guitar, bass, drums, vocals and keys,
and writes out the chords for guitar and bass and the lyrics. All done by AI, free, on your own computer.
Get started · Features · How it works · Technical notes
Features
Switch the guitar or bass off and take its place
The AI splits every song into six instruments: guitar, bass, drums, vocals, keys and the rest. One click mutes your
instrument so you can play it yourself, or plays it alone so you can learn the part. Every instrument has its own
fader, and the vocals switch on and off on top of any mode.
The chords for guitar and bass, worked out for you
PlayAlong listens to the song and writes out the chords bar by bar, with key and tempo: big for what to play now and
next with a beat counter, as a chart of the whole song, and on a timeline under the waveform. Set a capo or a
half step down tuning and the shapes change with it. Simple chords to start, full chords (7ths, sus, slash chords)
when you want them. Write them as chord names or roman numerals (Am F C G or vi IV I V).
Above the chart, every chord of the song shows once, in its colour, with how often it comes and how to finger
it: open chords, barre chords and the usual jazz voicings for 7th chords. Pick another fingering with the arrows;
the song remembers it, and the chord now and next show the same fingering. Above the chart, switch between Now &
next and Two rows of the chart that scroll along, each chord with its fingering. Every chord keeps the colour of its scale
degree everywhere (I orange, IV cyan, V blue …).
The Solo tab shows the scale of the key on a guitar or bass neck, in the five positions (or on the whole neck with
the position framed): pentatonic, full scale or blues, labelled with note names or scale degrees, with the relative
key (D major and B minor share their notes). Every note shows in the colour of its scale degree; position 1 of
the minor scale (position 5 in major, the same box) is chosen first. Switch on Solo along to improvise over the
changes: the chord's root (or all its notes) lights up on the neck, with the next chord fading in during the bar
before it, and the two rows of the chart scroll along above.
The Theory tab has an interactive circle of fifths with the song's key and its chords, and the seven modes with
their whole and half steps, the note that gives each its sound, and the chord on every degree.
The lyrics, with every chord on its word
Whisper, the speech AI, writes down what's sung, in English, German and about 100 other languages (even mixed in one
song). Each chord sits right above the word where it changes, and the sheet scrolls with the music like a
teleprompter. Click a line to jump there, Shift + click to loop it.
Bring any song
Paste the link of a YouTube video, or drag and drop an audio file (MP3, M4A, WAV, FLAC, OGG). Your songs are
kept, so they open instantly next time. In Chrome and Edge they can also live in a folder of your choice, as one
.playalong file each: put it in OneDrive, Dropbox or iCloud Drive and your songs are on all your computers. "Your
songs" shows where they are saved and lets you pick the folder; each song shows whether it is in the folder or only in
the browser, and downloads as a .playalong file that you can drop into PlayAlong anywhere. In the player, switch to
another song from the menu at the top or the list below.
Free, private, on your own computer
No upload, no account, no subscription. The AI runs inside your browser, on your graphics card through WebGPU
(or on the processor without one). A song takes a few minutes the first time and opens instantly after that.
And for practising
- Slow down to 50 % without the pitch changing
- Loop any passage: drag over the waveform, or Shift + click bars or lyric lines
- Download the backing track or any single instrument as WAV
- Keyboard shortcuts for everything (press
? in the player)
Get started
PlayAlong runs on your own computer, on Windows, macOS and Linux, with the same three steps.
1. Install Node.js 22 or newer (the LTS version) and git.
Nothing else: no Python, no account.
2. Open a terminal and run:
git clone https://github.com/simonroedig/PlayAlong.git
cd PlayAlong
npm install
npm run dev
No git? Download the ZIP, unpack it, open a
terminal in the folder and run npm install and npm run dev.
3. Open localhost:3000 in Chrome or Edge.
The first start downloads the AI models and the YouTube helper by itself (about 700 MB, once). After that it starts
right away. To stop it press Ctrl + C; next time just run npm run dev in the PlayAlong folder again.
Start it with a click (optional). Run this once in the PlayAlong folder:
npm run launcher
It puts a PlayAlong icon on your desktop and in the Start menu (Windows), in Applications (macOS) or in the app menu
(Linux). Pin it to the taskbar or dock like any other program. A click starts PlayAlong in the background and opens it
in your browser; it stops by itself 20 minutes after you close the last PlayAlong tab. The first click builds the app,
which takes a minute or two. After an update (git pull) PlayAlong shows "A new version is ready": click
Restart now and it rebuilds and reloads (or click the icon again). On Windows the icon opens Microsoft Edge (it can save
songs to a folder and use the graphics card); npm run launcher -- --browser=chrome or --browser=default changes
that. npm run launcher -- --remove takes the icon away again.
以上为 README 的开头部分。其余内容请阅读原文。 查看完整 README ↗
