Update README.md

README.md

@@ -38,9 +38,9 @@ dataset_info:
       dtype: string
   splits:
     - name: train
-      num_examples: 1508084
+      num_examples: 1511908
     - name: test
-      num_examples: 375639
+      num_examples: 372069
   download_size: 14615747
   dataset_size: 14615747
 ---
@@ -100,74 +100,63 @@ also not independently verified per-video (see [Known limitations](#known-limita
 
 ## Engine classes
 
-43 engine classes, 3,830 source videos, after exclusions below:
+34 engine classes, 3,877 source videos, after exclusions below:
 
 | Engine class | Files | Windows | Train | Test |
 | --- | --- | --- | --- | --- |
-| `2_rotor` | 18 | 3740 | 3372 | 368 |
-| `h12` | 10 | 4863 | 3981 | 882 |
-| `h2` | 92 | 56012 | 37044 | 18968 |
-| `h4` | 112 | 40657 | 34450 | 6207 |
-| `h6` | 97 | 84341 | 57384 | 26957 |
-| `i2_180` | 127 | 88771 | 66385 | 22386 |
-| `i2_180_two_stroke` | 41 | 9162 | 7007 | 2155 |
-| `i2_270` | 169 | 134456 | 104910 | 29546 |
-| `i2_360` | 63 | 24789 | 18457 | 6332 |
-| `i2_360_two_stroke` | 44 | 12124 | 10577 | 1547 |
-| `i3` | 133 | 57496 | 45440 | 12056 |
-| `i3_two_stroke` | 10 | 3219 | 2943 | 276 |
-| `i4` | 392 | 166630 | 131564 | 35066 |
-| `i4_crossplane` | 134 | 68221 | 48907 | 19314 |
-| `i4_diesel` | 75 | 31429 | 26944 | 4485 |
-| `i5` | 115 | 29789 | 24849 | 4940 |
-| `i5_diesel` | 52 | 21759 | 17435 | 4324 |
-| `i6` | 157 | 49570 | 35274 | 14296 |
-| `i6_diesel` | 52 | 29830 | 26165 | 3665 |
-| `single_four_stroke` | 101 | 42045 | 31663 | 10382 |
-| `single_two_stroke` | 94 | 44185 | 33465 | 10720 |
-| `v10_72` | 154 | 63020 | 46769 | 16251 |
-| `v10_90` | 14 | 11291 | 8406 | 2885 |
-| `v12` | 112 | 37882 | 35178 | 2704 |
-| `v16` | 8 | 4512 | 4512 | 0 |
-| `v2_45` | 138 | 165815 | 146284 | 19531 |
-| `v2_90` | 97 | 83045 | 73491 | 9554 |
-| `v2_two_stroke` | 11 | 2425 | 1915 | 510 |
-| `v4` | 80 | 31392 | 26760 | 4632 |
-| `v4_two_stroke` | 35 | 8369 | 6995 | 1374 |
-| `v6_120` | 72 | 31924 | 21840 | 10084 |
-| `v6_60` | 212 | 61043 | 47627 | 13416 |
-| `v6_90_even` | 58 | 36963 | 33490 | 3473 |
-| `v6_90_odd` | 5 | 3446 | 2629 | 817 |
-| `v6_diesel` | 16 | 3346 | 2502 | 844 |
-| `v8_60` | 18 | 6307 | 5173 | 1134 |
-| `v8_cross` | 264 | 139946 | 120989 | 18957 |
-| `v8_diesel` | 124 | 45184 | 35857 | 9327 |
-| `v8_flat` | 180 | 81189 | 68971 | 12218 |
-| `v8_voodoo` | 65 | 34937 | 27993 | 6944 |
-| `vr6` | 54 | 11260 | 6762 | 4498 |
-| `w12` | 19 | 8787 | 7173 | 1614 |
-| `w16` | 6 | 8552 | 8552 | 0 |
-
-Class sizes are heavily imbalanced (5 to 392 files per class) — account for this when
+| `2_rotor` | 141 | 43121 | 36452 | 6669 |
+| `h12` | 10 | 4863 | 3026 | 1837 |
+| `h2` | 92 | 56012 | 40333 | 15679 |
+| `h4` | 112 | 40657 | 32253 | 8404 |
+| `h6` | 97 | 84341 | 70911 | 13430 |
+| `i2_180` | 127 | 88771 | 73716 | 15055 |
+| `i2_180_two_stroke` | 41 | 9162 | 6487 | 2675 |
+| `i2_270` | 169 | 134456 | 110712 | 23744 |
+| `i2_360` | 63 | 24789 | 18944 | 5845 |
+| `i2_360_two_stroke` | 44 | 12124 | 11617 | 507 |
+| `i3` | 133 | 57496 | 45909 | 11587 |
+| `i4` | 394 | 168553 | 140949 | 27604 |
+| `i4_crossplane` | 134 | 68221 | 54634 | 13587 |
+| `i4_diesel` | 76 | 31606 | 27721 | 3885 |
+| `i5` | 115 | 29789 | 22419 | 7370 |
+| `i5_diesel` | 52 | 21759 | 19513 | 2246 |
+| `i6` | 157 | 49570 | 40540 | 9030 |
+| `i6_diesel` | 52 | 29830 | 11117 | 18713 |
+| `single_four_stroke` | 101 | 42045 | 29771 | 12274 |
+| `single_two_stroke` | 94 | 44185 | 35973 | 8212 |
+| `v10_72` | 156 | 63068 | 51501 | 11567 |
+| `v12` | 112 | 37882 | 26548 | 11334 |
+| `v2_45` | 138 | 165815 | 144387 | 21428 |
+| `v2_90` | 97 | 83045 | 75219 | 7826 |
+| `v4` | 80 | 31392 | 22601 | 8791 |
+| `v4_two_stroke` | 41 | 9750 | 7735 | 2015 |
+| `v6_120` | 72 | 31924 | 24099 | 7825 |
+| `v6_60` | 211 | 60753 | 48324 | 12429 |
+| `v6_90_even` | 76 | 43334 | 36442 | 6892 |
+| `v8_cross` | 265 | 140562 | 111631 | 28931 |
+| `v8_diesel` | 126 | 47716 | 30052 | 17664 |
+| `v8_flat` | 180 | 81189 | 65364 | 15825 |
+| `v8_voodoo` | 65 | 34937 | 24634 | 10303 |
+| `vr6` | 54 | 11260 | 10374 | 886 |
+
+Class sizes are heavily imbalanced (10 to 394 files per class) — account for this when
 sampling/weighting during training.
 
 ## Known limitations
 
 - **Weak, auto-derived labels.** `contains_target`/`quality_flag` come from an AudioSet-trained
   tagger's thresholded scores, not human review (see [Label semantics](#label-semantics)).
-- **Class imbalance.** File counts per class range from 5 (`v6_90_odd`) to 392 (`i4`).
-- **Two classes have zero test windows.** `v16` and `w16` have only 8 and 6 source videos
-  respectively; the per-video random 80/20 split happened to put every video from both classes
-  into `train`. Don't evaluate on these classes without re-splitting.
-- **97 ambiguous videos were excluded.** Cross-referencing every video id against every
-  engine_class it was scraped under found 97 YouTube videos that had been pulled into **more
-  than one conflicting engine_class** (almost certainly multi-engine compilation/comparison
-  videos caught by more than one search query, e.g. one video labeled both `v2_90` and `v4`,
-  another labeled across `i4_diesel`/`i6_diesel`/`v10_90`/`v8_diesel` simultaneously). All
-  windows sourced from any of these videos were dropped entirely (110,830 of 1,994,553 rows,
-  5.6%) rather than guessing which label was correct. This hit some already-small classes hard:
-  `v2_two_stroke` went from 19 to 11 files, `h12` from 18 to 10, `v10_90` from 19 to 14. The
-  class table above already reflects these counts.
+- **Class imbalance.** File counts per class range from 10 (`h12`) to 394 (`i4`).
+- **All classes have representation in both train and test sets** (no class has zero test windows
+  after conflict exclusions).
+- **Cross-class conflicts.** Cross-referencing every video id against every engine_class it was
+  scraped under found videos that had been pulled into **more than one conflicting engine_class**
+  (almost certainly multi-engine compilation/comparison videos caught by more than one search
+  query). All windows sourced from any of these videos were dropped entirely (99,105 of
+  1,983,082 rows, 5.0%) rather than guessing which label was correct. This also resulted in
+  9 engine classes being dropped entirely from the export (they had no videos that didn't also
+  appear in at least one conflicting class). The class table above reflects the final, post-conflict
+  list.
 - **Link rot.** Since only YouTube ids are published (see [Why metadata-only](#why-metadata-only)),
   some fraction of source videos will become unavailable over time as creators delete or
   privatize them — unlike a self-hosted audio dataset, this one can shrink on its own.
@@ -196,4 +185,4 @@ The labels, timestamps, and ids in this repository are released under `cc-by-sa-
 **not** extend any rights to the underlying YouTube video content, which remains the property of
 its original creators — this dataset does not redistribute, host, or relicense that audio.
 Commercial users should independently verify their own right to use any audio they fetch via the
-ids in this dataset.
+ids in this dataset.