#!/usr/bin/env python3 """Independently inspect these two MIDI fixtures with mido; no encoder imports.""" from pathlib import Path from importlib.metadata import version from datetime import datetime, timezone import hashlib import json import struct import mido HERE = Path(__file__).resolve().parent EXPORTER_SHA = 'ce7336d07f8cd4e21fc1eb9f244f207b6db58693a3e015ef69ec392214dc4e79' EXPECTED_NOTES = [ {'channel': 0, 'pitch': 60, 'start_tick': 480, 'end_tick': 1440, 'velocity': 80}, {'channel': 0, 'pitch': 64, 'start_tick': 1920, 'end_tick': 2880, 'velocity': 80}, ] def require(condition, reason): if not condition: raise ValueError(reason) def sha(path): return hashlib.sha256(path.read_bytes()).hexdigest() def parse(filename, expected_eot): path = HERE / filename raw = path.read_bytes() require(len(raw) >= 22 and raw[:4] == b'MThd', 'Missing SMF header') header = struct.unpack('>IHHH', raw[4:14]) require(header == (6, 0, 1, 960), 'Expected SMF0, one track, 960 PPQ') require(raw[14:18] == b'MTrk', 'Missing MIDI track') require(struct.unpack('>I', raw[18:22])[0] == len(raw)-22, 'Track size must cover the exact complete file') midi = mido.MidiFile(path) require((midi.type, len(midi.tracks), midi.ticks_per_beat) == (0, 1, 960), 'Parsed header mismatch') tick = 0 active = {} notes = [] events = [] tempos = [] eots = [] last_off = None for index, message in enumerate(midi.tracks[0]): require(isinstance(message.time, int) and message.time >= 0, 'Invalid delta ticks') tick += message.time require(message.type in ('set_tempo', 'program_change', 'note_on', 'note_off', 'end_of_track'), 'Unexpected event in the control fixture') payload = message.dict() delta = payload.pop('time') events.append({'absolute_tick': tick, 'delta_tick': delta, **payload}) if message.type == 'set_tempo': tempos.append({'tick': tick, 'microseconds_per_beat': message.tempo}) elif message.type == 'end_of_track': eots.append(tick) require(index == len(midi.tracks[0])-1, 'Events after End-of-Track') elif message.type in ('note_on', 'note_off'): key = (message.channel, message.note) if message.type == 'note_on' and message.velocity > 0: require(key not in active, 'Overlapping same-pitch note-on') active[key] = (tick, message.velocity) else: require(key in active, 'Orphan note-off') start, velocity = active.pop(key) require(tick > start, 'Nonpositive note duration') last_off = tick notes.append({'channel': message.channel, 'pitch': message.note, 'start_tick': start, 'end_tick': tick, 'velocity': velocity}) require(not active, 'Hanging note-on') require(tempos == [{'tick': 0, 'microseconds_per_beat': 500000}], 'Expected fixed tempo at zero') require(eots == [expected_eot], 'Unexpected End-of-Track tick') require(notes == EXPECTED_NOTES, 'Actual note events differ from the fixed independent tick expectations') require(last_off == 2880 and expected_eot >= last_off, 'Unexpected last note-off') seconds = lambda ticks: mido.tick2second(ticks, 960, 500000) return {'status': 'passed', 'file': filename, 'bytes': len(raw), 'sha256': sha(path), 'smf_type': midi.type, 'tracks': 1, 'ppq': 960, 'tempos': tempos, 'note_count': len(notes), 'notes': notes, 'events': events, 'last_note_off_tick': last_off, 'last_note_off_seconds': seconds(last_off), 'end_of_track_tick': expected_eot, 'end_of_track_seconds': seconds(expected_eot), 'note_free_track_tail_ticks': expected_eot-last_off, 'note_free_track_tail_seconds': seconds(expected_eot-last_off), 'strict_checks': {'exact_track_chunk_length': True, 'positive_paired_notes': True, 'orphan_note_off_count': 0, 'hanging_note_on_count': 0, 'same_pitch_overlap_count': 0, 'single_final_end_of_track': True}} def main(): require(version('mido') == '1.3.3', 'Expected the existing mido 1.3.3 runtime') exporter = HERE/'midi-file.js' require(sha(exporter) == EXPORTER_SHA, 'Frozen exporter copy hash differs') files = [parse('same-notes-1.5s.mid', 2880), parse('same-notes-4.0s.mid', 7680)] without_eot = lambda item: [event for event in item['events'] if event['type'] != 'end_of_track'] require(without_eot(files[0]) == without_eot(files[1]), 'Non-EOT events changed') result = {'status': 'passed_internal_synthetic_export_control', 'recorded_at': datetime.now(timezone.utc).isoformat(), 'mido_version': version('mido'), 'scope': 'Pure-exporter self-authored CC0 note control; no audio input, browser conversion, DAW import or acoustic tail test.', 'source_provenance': {'original': 'dist/midi-file.js', 'frozen_copy': 'midi-file.js', 'sha256': EXPORTER_SHA, 'source_release': '780d9051-28ca-4d8f-81b0-6deb08db54a3', 'generator': 'generate.cjs', 'generator_sha256': sha(HERE/'generate.cjs'), 'independent_parser': 'verify.py', 'independent_parser_sha256': sha(Path(__file__)), 'parser_calls_or_imports_encoder': False}, 'input_notes': [{'pitch': 60, 'start': 0.25, 'end': 0.75, 'velocity': 80}, {'pitch': 64, 'start': 1.0, 'end': 1.5, 'velocity': 80}], 'only_generator_input_changed': 'duration: 1.5 seconds versus 4.0 seconds', 'files': files, 'comparison': {'non_eot_events_identical': True, 'identical_non_eot_event_count': len(without_eot(files[0])), 'last_note_off_identical': True, 'end_of_track_delta_ticks': 4800, 'end_of_track_delta_seconds': 2.5, 'raw_files_identical': False, 'raw_byte_difference_explanation': 'The End-of-Track delta-time and its encoded byte length change; the track chunk length changes accordingly.'}, 'limits': ['Track event duration and note-free trailing time are not acoustic instrument release or rendered audio silence.', 'No audio transcription, app/DAW import, playback, listening, browser or device test was performed.', 'Internal candidate material only; not a new product page, exclusive capability claim or verified common search-results gap.', 'CC0 applies to the self-authored note fixture/generated MIDI material; the copied exporter retains its project provenance.']} (HERE/'measurements.json').write_text(json.dumps(result, ensure_ascii=False, indent=2)+'\n') print('passed: identical 6 non-EOT events; last note-off=2880; EOT=2880/7680; note-free tail=0/2.5s') if __name__ == '__main__': main()