--- a
+++ b/tools/convert_datasets/cityscapes.py
@@ -0,0 +1,56 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import argparse
+import os.path as osp
+
+import mmcv
+from cityscapesscripts.preparation.json2labelImg import json2labelImg
+
+
+def convert_json_to_label(json_file):
+    label_file = json_file.replace('_polygons.json', '_labelTrainIds.png')
+    json2labelImg(json_file, label_file, 'trainIds')
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description='Convert Cityscapes annotations to TrainIds')
+    parser.add_argument('cityscapes_path', help='cityscapes data path')
+    parser.add_argument('--gt-dir', default='gtFine', type=str)
+    parser.add_argument('-o', '--out-dir', help='output path')
+    parser.add_argument(
+        '--nproc', default=1, type=int, help='number of process')
+    args = parser.parse_args()
+    return args
+
+
+def main():
+    args = parse_args()
+    cityscapes_path = args.cityscapes_path
+    out_dir = args.out_dir if args.out_dir else cityscapes_path
+    mmcv.mkdir_or_exist(out_dir)
+
+    gt_dir = osp.join(cityscapes_path, args.gt_dir)
+
+    poly_files = []
+    for poly in mmcv.scandir(gt_dir, '_polygons.json', recursive=True):
+        poly_file = osp.join(gt_dir, poly)
+        poly_files.append(poly_file)
+    if args.nproc > 1:
+        mmcv.track_parallel_progress(convert_json_to_label, poly_files,
+                                     args.nproc)
+    else:
+        mmcv.track_progress(convert_json_to_label, poly_files)
+
+    split_names = ['train', 'val', 'test']
+
+    for split in split_names:
+        filenames = []
+        for poly in mmcv.scandir(
+                osp.join(gt_dir, split), '_polygons.json', recursive=True):
+            filenames.append(poly.replace('_gtFine_polygons.json', ''))
+        with open(osp.join(out_dir, f'{split}.txt'), 'w') as f:
+            f.writelines(f + '\n' for f in filenames)
+
+
+if __name__ == '__main__':
+    main()