Creating Music for Emotes

An emote can carry its own sound. Put an .opus file in the emotes folder next to the emote and give it the same name, and Emotecraft plays it whenever the emote plays — for you and for everyone who sees you.

emotes/
  wave.json
  wave.opus

The sound travels with the emote, so other players hear it without having to download anything themselves.

What .opus is

Nothing special, and nothing invented for this mod. Opus is an ordinary audio format, the same one Discord and most voice chats use, and .opus is simply an audio file holding it. Emotecraft asks for it because it stays small: a few hundred kilobytes for a whole song, which is what makes sending the sound along with the emote possible at all.

Playing one back depends on your system:

Windows 10 and 11	opens as is
Linux, Android	opens as is
macOS	QuickTime and Music cannot, VLC can
Anywhere	drag the file into a Chrome or Firefox window

That browser trick is the quickest way to check a file without installing anything, and the converter below lets you listen to the result before you download it at all.

Making the file

The easiest way is the Emote Sound Converter. Drop in any audio file, choose how it should sound, and download the result. It runs entirely in your browser, nothing is uploaded anywhere, and it will not let you make a file the mod would reject.

If you would rather do it yourself, ffmpeg does the same job:

ffmpeg -i song.mp3 -af "pan=mono|c0=0.5*c0+0.5*c1,alimiter=level=disabled:limit=0.9" \
  -c:a libopus -b:a 32k -vbr constrained -ar 48000 wave.opus

Do not reach for -ac 1 to make it mono. It adds the two channels together without halving them, which is 6 dB of gain the track never asked for, and everything above full scale comes back as crackling. The pan filter mixes them properly, and the limiter catches the overshoot the encoder itself adds at low bitrates. level=disabled matters: without it the limiter puts the level straight back.

The sound has to be mono. Everything else below is a limit rather than a requirement.

Looping

By default the sound plays once, even if the emote itself repeats forever. To make it loop, add a LOOPSTART tag saying which sample it should jump back to. There are 48000 samples in a second, so LOOPSTART=96000 restarts from the two second mark:

ffmpeg -i song.mp3 -af "pan=mono|c0=0.5*c0+0.5*c1,alimiter=level=disabled:limit=0.9" \
  -c:a libopus -b:a 32k -vbr constrained -ar 48000 -metadata LOOPSTART=96000 wave.opus

Use LOOPSTART=0 to simply start over from the beginning. A later value is for tracks with an intro that should only be heard once. The converter has a checkbox for this and works the number out for you.

Both ends are honoured to the sample. An encoder pads its last frame out to a whole 20 ms, and that padding is dropped rather than played, so a track that was seamless stays seamless.

The sound and the animation loop independently, each on its own length, so they drift apart over time unless they happen to line up.

Limits

Channels	mono only
Size	1 MB, shared with the emote itself
Bitrate	96 kbps, and low enough to fit the size limit
Length	10 minutes

The size limit is the one you will actually run into: it is the largest packet a Minecraft server will pass along, and the animation has to fit in it too. At 32 kbps that is roughly four and a half minutes of music, which is plenty for most emotes. If the sound does not fit, the emote still plays — just silently for everyone else.

Volume

Emotecraft measures how loud each sound is and evens them out, so that a quiet emote and a loud one sit at the same level. Do not normalise or amplify the file yourself; leave it as it is. Players who prefer the original loudness can turn this off with Normalize the volume of emote sounds in the options.

If the file carries an R128_TRACK_GAIN tag, that is used instead of measuring, which saves a little work when the emote loads.

Note Block Studio (legacy)

Older versions used Note Block Studio songs saved as \{nameOfEmoteFile\}.nbs. Current versions no longer play them.

They are still passed along, though, so an emote can carry both files at once:

emotes/
  wave.json
  wave.opus
  wave.nbs

Everyone hears something. Players on a current version get the .opus; players on an older one get the .nbs, because the mod keeps sending it to anyone who cannot read Opus. A server passes on whichever one each player is able to play, so a single pack works across versions.

If you are publishing an emote that already has a .nbs, keeping it costs a few kilobytes and loses nothing. Only the .opus is sent to modern clients; the .nbs travels alongside it when an emote is stored, and on its own when the other side is old.

Emotes from EmotecraftLibrary (RedlanceEmotes) need none of this: the library generates the .opus for every emote that has a .nbs, so downloads already carry both.

Useful links

• Emote Sound Converter - Turn any audio file into an emote sound, in your browser.
• Note Block World - The largest public community centered around Minecraft note blocks.
• Note Block Tool - Tool for importing, exporting, batch manipulating and playing Minecraft note block songs.