Script used to merge two very large .nbs files for the first Note Block Megacollab, totaling over 250,000 notes.

megacollab_merger.py

import copy
import pynbs
import shutil
import os


file1 = "megacollab parts 1-28.nbs"
file2 = "megacollab parts 29-50.nbs"
output_file = "megacollab_merged.nbs"


song1 = pynbs.read(file1)
song2 = pynbs.read(file2)

INS_COUNT = song1.header.default_instruments


# Offset instrument IDs from the second song (so the IDs don't overlap)
offset = 1000
for id, ins in enumerate(song2.instruments):
    ins.id += offset
for note in song2.notes:
    if note.instrument >= INS_COUNT:
        note.instrument += offset


# Clean up, merge and remove unused instruments
all_instruments = song1.instruments + song2.instruments
used_instruments = set(note.instrument - INS_COUNT for note in song1.notes + song2.notes if note.instrument >= INS_COUNT)
merged_instruments_lookup = {}  # Maps old instrument IDs to new instrument IDs
merged_instruments = []  # List of merged instruments
seen = []
for ins in all_instruments:
    if ins.id not in used_instruments:
        continue
    if ins.file in seen:
        merged_instruments_lookup[ins.id] = seen.index(ins.file)
    else:
        id = len(merged_instruments)
        merged_instruments_lookup[ins.id] = id
        seen.append(ins.file)
        new_ins = pynbs.Instrument(id, ins.name, ins.file, ins.pitch)
        merged_instruments.append(new_ins)


# Rename and normalize instrument paths
seen = []
for ins in merged_instruments:
    if ins.file == "":
        continue
    old_path = os.path.join("instruments", ins.file.replace("/", os.sep))
    filename, ext = os.path.splitext(ins.file.split("/")[-1])
    if filename in seen:  # avoid duplicate filenames
        suffix = f"_{seen.count(filename) + 1}"
    else:
        suffix = ""
    new_path = f"Megacollab/{filename}{suffix}{ext}"
    shutil.copy(old_path, new_path)
    ins.file = new_path
    seen.append(filename)


# Zip up the instrument files
shutil.make_archive("megacollab_merged - Instruments", "zip", "Megacollab")


# Merge notes
song1_notes = song1.notes
song2_notes = []
tick_offset = max(note.tick for note in song1.notes) + 1
for note in song2.notes:
    note.tick += tick_offset
    song2_notes.append(note)
merged_notes: list[pynbs.Note] = song1_notes + song2_notes


# Fix note instruments
for note in merged_notes:
    if note.instrument >= INS_COUNT:
        note.instrument = merged_instruments_lookup[note.instrument - INS_COUNT] + INS_COUNT


# Merge stats
merged_header = song1.header
merged_header.minutes_spent += song2.header.minutes_spent
merged_header.left_clicks += song2.header.left_clicks
merged_header.right_clicks += song2.header.right_clicks
merged_header.blocks_added += song2.header.blocks_added
merged_header.blocks_removed += song2.header.blocks_removed


# Add song info
merged_header.song_name = "Note Block Megacollab"


# Populate layers
last_layer_id = max(note.layer for note in merged_notes)
merged_layers = [pynbs.Layer(id) for id in range(last_layer_id + 1)]


# Stats!
print("Ticks:", max(note.tick for note in merged_notes) + 1)
print("Layers:", max(note.layer for note in merged_notes) + 1)
print("Instruments:", max(note.instrument for note in merged_notes) + 1)


# Add starting tempo changers
tempo_changer_id = [ins for ins in merged_instruments if ins.name == "Tempo Changer"][0].id
note1 = pynbs.Note(
    tick=0,
    layer=110,
    instrument=tempo_changer_id + INS_COUNT,
    key=39,
    pitch=int(song1.header.tempo * 15)
)
merged_notes.append(note1)
note2 = copy.copy(note1)
note2.tick += 1
merged_notes.append(note2)


# Create final song file
final_song = pynbs.File(
    merged_header,
    merged_notes,
    merged_layers,
    merged_instruments,
)
final_song.save(output_file)