Free online FLAC to NBS converter

NBS files are Minecraft Note Block Studio song files, not audio containers, so a FLAC recording cannot be converted into NBS as a direct waveform-preserving format change. The practical workflow is to detect notes from the recording, export them as MIDI, then import the MIDI into Note Block Studio and save an NBS project.

What the FLAC format is

FLAC (Free Lossless Audio Codec) stores compressed digital audio without discarding source samples. Music players, CD-ripping tools, audio editors, and archival applications commonly create or use .flac files. FLAC can contain complete recordings with vocals, effects, and multiple instruments, while NBS stores discrete note events rather than recorded sound.

What the NBS format is

NBS is the song format associated with Note Block Studio and Open Note Block Studio for creating Minecraft note-block songs. An .nbs file stores pitches, timing, instruments, layers, and note-block arrangement data. It is useful for editing a song as Minecraft note blocks, but it cannot represent arbitrary vocals, reverb, drum recordings, or other continuous audio accurately.

How to actually convert FLAC to NBS

1. Prepare a clean recording containing a distinct melody. Dense mixes, vocals, percussion, and reverberation reduce note-detection accuracy.
2. Convert the FLAC to WAV if the transcription program does not accept FLAC. FFmpeg can do this without changing the decoded audio:
   ffmpeg -i input.flac -c:a pcm_s16le input.wav
3. Use an audio-to-MIDI transcription tool such as Spotify Basic Pitch to create a MIDI file. Basic Pitch can detect pitch and timing, but it normally needs manual correction for polyphonic recordings and complete arrangements.
4. Open Note Block Studio or the original Note Block Studio, choose File → Import MIDI (the wording varies by version), and select the generated .mid file.
5. Correct wrong pitches, note lengths, tempo, instrument assignments, octave range, and overlapping notes. Minecraft note blocks support a limited pitch range, so notes outside that range must be transposed or removed.
6. Save the project with File → Save or File → Save As and select the .nbs format.

You can also check 101convert.com for a free browser conversion option without installing software. Because FLAC is audio and NBS is a note-event format, an online tool can only produce a useful result if it includes audio transcription; a simple file re-encoding cannot preserve the recording in NBS.

Quality, compatibility, and limitations

This process is transcription, not lossless conversion. The NBS result contains an approximation of detected notes and cannot retain the original FLAC waveform, vocals, sound design, dynamics, or exact performance.

Use a single-instrument or melody-focused source for the best result. For a full song, transcribe separate stems when possible, import or edit each MIDI part independently, and verify that the target Note Block Studio version supports the instruments and NBS features you use. Keep the original FLAC and MIDI files because later NBS editing cannot reconstruct information lost during transcription.