This dataset is the maestro dataset, formatted in the WebDataset format. WebDataset files are essentially tar archives, where each example in the dataset is represented by a pair of files: a WAV audio file and a corresponding JSON metadata file. The JSON file contains the class label and other relevant information for that particular audio sample. $ tar tvf maestro_train_000000.tar|head -r--r--r-- bigdata/bigdata 327458 2025-01-23 13:26 MIDI-Unprocessed_XP_15_R2_2004_01_ORIG_MID--AUDIO_15_R2_2004_02_Track02_wav.json -r--r--r-- bigdata/bigdata 120375940 2025-01-23 13:26 MIDI-Unprocessed_XP_15_R2_2004_01_ORIG_MID--AUDIO_15_R2_2004_02_Track02_wav.wav -r--r--r-- bigdata/bigdata 625054 2025-01-23 13:26 MIDI-Unprocessed_13_R1_2009_01-03_ORIG_MID--AUDIO_13_R1_2009_13_R1_2009_03_WAV.json -r--r--r-- bigdata/bigdata 137713368 2025-01-23 13:26 MIDI-Unprocessed_13_R1_2009_01-03_ORIG_MID--AUDIO_13_R1_2009_13_R1_2009_03_WAV.wav -r--r--r-- bigdata/bigdata 356393 2025-01-23 13:26 MIDI-Unprocessed_XP_17_R2_2004_01_ORIG_MID--AUDIO_17_R2_2004_01_Track01_wav.json -r--r--r-- bigdata/bigdata 132159804 2025-01-23 13:26 MIDI-Unprocessed_XP_17_R2_2004_01_ORIG_MID--AUDIO_17_R2_2004_01_Track01_wav.wav -r--r--r-- bigdata/bigdata 255210 2025-01-23 13:26 ORIG-MIDI_01_7_6_13_Group__MID--AUDIO_01_R1_2013_wav--2.json -r--r--r-- bigdata/bigdata 58523088 2025-01-23 13:26 ORIG-MIDI_01_7_6_13_Group__MID--AUDIO_01_R1_2013_wav--2.wav -r--r--r-- bigdata/bigdata 1190145 2025-01-23 13:26 MIDI-UNPROCESSED_04-07-08-10-12-15-17_R2_2014_MID--AUDIO_17_R2_2014_wav.json -r--r--r-- bigdata/bigdata 390151460 2025-01-23 13:26 MIDI-UNPROCESSED_04-07-08-10-12-15-17_R2_2014_MID--AUDIO_17_R2_2014_wav.wav $ cat ORIG-MIDI_01_7_6_13_Group__MID--AUDIO_01_R1_2013_wav--2.json [ ... {"start": 323.546875, "end": 323.5859375, "note": 51}, {"start": 323.703125, "end": 323.74869791666663, "note": 51}, {"start": 323.8450520833333, "end": 323.8919270833333, "note": 51}, {"start": 324.00390625, "end": 324.0442708333333, "note": 51}, ... ]