[Feature] Add argument 'repeat' to SRREDSMultipleGTDataset

configs/restorers/basicvsr_plusplus/basicvsr_plusplus_c64n7_8x1_600k_reds4.py

@@ -102,6 +102,7 @@
         pipeline=test_pipeline,
         scale=4,
         val_partition='REDS4',
+        repeat=2,
         test_mode=True),
     # test
     test=dict(

mmedit/datasets/sr_reds_multiple_gt_dataset.py

@@ -19,6 +19,9 @@ class SRREDSMultipleGTDataset(BaseSRDataset):
         scale (int): Upsampling scale ratio.
         val_partition (str): Validation partition mode. Choices ['official' or
         'REDS4']. Default: 'official'.
+        repeat (int): Number of replication of the validation set. This is used
+            to allow training REDS4 with more than 4 GPUs. For example, if
+            8 GPUs are used, this number can be set to 2. Default: 1.
         test_mode (bool): Store `True` when building test dataset.
             Default: `False`.
     """
@@ -30,7 +33,14 @@ def __init__(self,
                  pipeline,
                  scale,
                  val_partition='official',
+                 repeat=1,
                  test_mode=False):
+
+        self.repeat = repeat
+        if not isinstance(repeat, int):
+            raise TypeError('"repeat" must be an integer, but got '
+                            f'{type(repeat)}.')
+
         super().__init__(pipeline, scale, test_mode)
         self.lq_folder = str(lq_folder)
         self.gt_folder = str(gt_folder)
@@ -58,6 +68,7 @@ def load_annotations(self):
 
         if self.test_mode:
             keys = [v for v in keys if v in val_partition]
+            keys *= self.repeat
         else:
             keys = [v for v in keys if v not in val_partition]
 

tests/test_data/test_datasets/test_sr_dataset.py

@@ -788,6 +788,37 @@ def test_sr_reds_multiple_gt_dataset():
         sequence_length=100,
         num_input_frames=5)
 
+    # REDS4 val partition (repeat > 1)
+    reds_dataset = SRREDSMultipleGTDataset(
+        lq_folder=root_path,
+        gt_folder=root_path,
+        num_input_frames=5,
+        pipeline=[],
+        scale=4,
+        val_partition='REDS4',
+        repeat=2,
+        test_mode=True)
+
+    assert len(reds_dataset.data_infos) == 8  # 4 test clips
+    assert reds_dataset.data_infos[5] == dict(
+        lq_path=str(root_path),
+        gt_path=str(root_path),
+        key='011',
+        sequence_length=100,
+        num_input_frames=5)
+
+    # REDS4 val partition (repeat != int)
+    with pytest.raises(TypeError):
+        SRREDSMultipleGTDataset(
+            lq_folder=root_path,
+            gt_folder=root_path,
+            num_input_frames=5,
+            pipeline=[],
+            scale=4,
+            val_partition='REDS4',
+            repeat=1.5,
+            test_mode=True)
+
 
 def test_sr_vimeo90k_mutiple_gt_dataset():
     root_path = Path(__file__).parent.parent.parent / 'data/vimeo90k'