Loudness and broadcasting

openDJ streams your mix to internet radio (Icecast and Shoutcast servers) and measures its loudness as it plays, so you can hit the level your station or platform asks for.

Streaming to a radio station

Your station or streaming host gives you a server address, a port, a mount point and a source password. Put them into openDJ once:

1. Open Settings › Broadcast, switch on Broadcasting, and click Add next to Add a station.
2. Fill in Address, Port, Mount point (Icecast) and Password. Leave User as source unless your host says otherwise.
3. Choose the Format and Bitrate. MP3 at 128 kb/s plays everywhere and shows listeners each track's title. Opus sounds better at low bitrates (96 kb/s is plenty).
4. Click Test. openDJ connects, checks the password and hangs up, without going on air.

The password is kept in your system's keychain (Keychain on macOS, Credential Manager on Windows, the Secret Service on Linux), never in openDJ's settings file. Where there's no keychain, openDJ remembers it until you quit.

You can add several stations and switch each on or off: ON AIR streams to every station that's switched on, at once. The ON AIR button only shows in the top bar while Broadcasting is on and at least one station is set up and switched on.

Going on air

Click ON AIR in the top bar, then Go on air. The button turns red and counts the time on air. Each station gets a light:

If the connection drops, openDJ reconnects at once and then every 5 seconds, for up to 10 minutes. A slow upload never makes the music stutter: if it falls more than about 10 seconds behind, openDJ reconnects that station and carries on from now. Icecast servers also report how many people are listening, next to the time.

Click Go off air to stop. Controllers with a broadcast button (mapped to Mixxx's [Shoutcast],enabled) go on and off air too.

What listeners see

Listeners see the track that's heard most (playing, with its channel fader up, on the crossfader's live side), a couple of seconds after it takes over, so a quick cut back and forth doesn't flicker. Change the text in Settings › Broadcast › Title sent to listeners: {artist}, {title} and {dj} are filled in, and plain text such as Live from the club is sent as it is.

MP3 streams update the title on the server, which every player shows. Opus carries titles inside the stream: the first title always goes out, and later ones only with Send each new title in the stream, because starting the stream again at each track stops some players.

Now playing in OBS

Streaming on Twitch or YouTube with OBS or Streamlabs? Switch on Settings › Broadcast › Now playing for streaming software to show the track on screen. It follows the same track listeners would see, once it has been heard for the Changes after time (10 seconds at first), and works without a radio station.

• The overlay page: in OBS add a Browser Source with the address shown under the switch (such as http://127.0.0.1:7487/now-playing), 1920 × 1080. Its background is clear, so only the card with the cover, artist and title shows, and it fades from one track to the next. Pick Lower third, Corner or Ticker under Overlay style; the page follows without being reloaded. It is read only, and only this computer can open it unless you switch on Open to other devices.
• The text file: in OBS add a Text source, tick Read from file and pick now-playing.txt in the Files folder (Music/openDJ/Now Playing at first). Its line is {artist} - {title}; change it under Text file line, with {album}, {label}, {genre}, {bpm} and {key} too.
• now-playing.json, beside it, has the track, its BPM, key, deck and start time, and the ten tracks before it, for chat bots and other tools. The same JSON is at /now-playing.json on the overlay's address.

Scrobbling to ListenBrainz

Switch on Settings › Broadcast › Send plays to ListenBrainz and paste your user token (from listenbrainz.org, under Settings) into ListenBrainz token. Each track the audience hears then goes to your ListenBrainz profile, from any layout, as a music player's plays do: it shows as playing now after a few seconds, and counts as a listen once half of it, or four minutes, has played (tracks under 30 seconds never count). Tracks you only cue in the headphones are left out. Without a connection, plays wait and go once ListenBrainz answers again. Under the token it says who you are signed in as and how many plays were sent.

Scrobbling to Last.fm

The same plays can go to Last.fm. It needs a free API account of your own: make one at last.fm/api/account/create (any name and description; leave the callback empty), then switch on Send plays to Last.fm, paste the API key and shared secret, and press Sign in. Last.fm opens in the browser; allow openDJ there, and Settings says who you are signed in as. Sign out forgets the session. Both services can be on at once.

Licences

Playing other people's music to the public needs licences in most countries, from bodies such as PRS, GEMA, SACEM, ASCAP, BMI and SoundExchange. Many radio hosts include them; check yours before you go on air.

The loudness meter

Open the ON AIR button in the top bar. Under Go on air, Loudness shows:

The readings are green within 1 LU of your target, amber within 3 and red further off. Reset starts integrated loudness, the range and the true peak again. They also start again when you press REC or go on air.

While recording, the REC button in the top bar shows the short-term loudness next to the time.

Choosing a target

Pick the target in Settings › Audio › Loudness:

The target only colors the meter: it doesn't change any level. To move your mix, turn the master down (or up) until the short-term reading sits green most of the time. With Auto gain on (Settings › Mixer), every track already starts at the same loudness, so the mix stays close once it's set.

The limiter while recording or on air

The master always runs through a limiter, so the mix never clips. While you record or are on air, it also keeps the peaks between samples under −1 dB true peak, which MP3, AAC and Opus need so they don't distort. For streams at low bitrates (96 kb/s or less), choose −2 dBTP in Settings › Audio › Loudness.

The headphones and booth don't go through the limiter (they would lag behind the master), so they have a soft clipper instead: nothing changes below −1.5 dBFS, and louder peaks are bent smoothly under full scale rather than squared off.

For controllers