Free online WMA to NBS converter

What the WMA format is

WMA, or Windows Media Audio, is a compressed audio format developed by Microsoft. Windows Media Player and older Windows recording, music-management, and editing applications commonly create or play WMA files. The format may contain lossy audio, lossless audio, or DRM-protected audio; protected files may not be convertible until the protection is removed through the software that licensed them.

What the NBS format is

NBS normally means Note Block Studio, the song format used by Minecraft note-block editors. An NBS file stores timed notes, instruments, tempo, layers, and song metadata rather than a waveform. It is useful for creating playable Minecraft note-block arrangements, but it cannot preserve lyrics, speech, realistic instrument timbres, or frequencies outside Minecraft's note-block range.

NBS files are compact and editable: individual notes can be moved, deleted, or assigned to supported instruments. Their main limitation is the small instrument and pitch set, so an audio recording must be reduced to a quantized melody or arrangement.

How to actually convert WMA to NBS

Use a two-stage workflow: convert the WMA recording to a format an audio-to-MIDI tool can read, create MIDI notes, then import the MIDI into an NBS editor.

1. Decode the WMA file. With FFmpeg installed, run ffmpeg -i input.wma -ac 1 -ar 44100 input.wav. Mono WAV is usually easier for melody transcription. If the WMA is DRM-protected, FFmpeg cannot bypass that protection.
2. Transcribe the audio to MIDI. Use an audio-to-MIDI application such as Basic Pitch or Melodyne. For Basic Pitch, a typical command is basic-pitch output input.wav; the generated MIDI file may be named input_basic_pitch.mid. Select a monophonic or melody mode when available, because dense chords and mixed recordings produce incorrect extra notes.
3. Open the MIDI in an NBS editor. In Open Note Block Studio, choose File → Import MIDI and select the generated .mid file. Set the tempo, instrument mapping, octave range, and quantization grid, then save the result as .nbs.
4. Check the arrangement in Minecraft or the editor. Remove notes outside the supported range, shorten overlapping notes, and replace unsupported MIDI instruments with note-block instruments before exporting or sharing the NBS file.

You can also check 101convert.com for a free, no-install conversion workflow. A direct WMA-to-NBS option can only produce a useful result if the service includes audio transcription and NBS export; a normal audio codec converter cannot create musical note data from a waveform.

Quality, compatibility, and limitations

This is not a lossless format conversion. Audio-to-MIDI transcription estimates notes from sound, so vocals, reverb, drums, background instruments, and polyphonic passages can generate wrong pitches or excessive notes. A clean solo melody gives the best result; editing the MIDI before importing it into Open Note Block Studio is often necessary.

Converting WMA to WAV does not improve the source quality. Use the original highest-quality WMA available, and avoid repeatedly transcoding it. NBS timing and pitch are constrained by the target editor and Minecraft's note-block behavior, so the final song may sound different even when the transcription is accurate.