Generate suggestions for videos with less frames than samples per video

sleap/gui/suggestions.py

@@ -80,9 +80,11 @@ def basic_sample_suggestion_method(
 
         for video in labels.videos:
             if sampling_method == "stride":
-                vid_suggestions = list(
-                    range(0, video.frames, video.frames // per_video)
-                )[:per_video]
+                frame_increment = video.frames // per_video
+                frame_increment = per_video if frame_increment == 0 else frame_increment
+                vid_suggestions = list(range(0, video.frames, frame_increment))[
+                    :per_video
+                ]
             else:
                 # random sampling
                 vid_suggestions = random.sample(range(video.frames), per_video)

tests/gui/test_suggestions.py

@@ -1,4 +1,5 @@
 from sleap.gui.suggestions import VideoFrameSuggestions
+from sleap.io.dataset import Labels
 
 
 def test_velocity_suggestions(centered_pair_predictions):
@@ -9,3 +10,33 @@ def test_velocity_suggestions(centered_pair_predictions):
     assert len(suggestions) == 45
     assert suggestions[0].frame_idx == 21
     assert suggestions[1].frame_idx == 45
+
+
+def test_frame_increment(centered_pair_predictions: Labels):
+
+    # Testing videos that have less frames than desired Samples per Video value using stride method.
+    # Expected result is one suggested frame.
+
+    vid_frames = centered_pair_predictions.video.num_frames
+    suggestions = VideoFrameSuggestions.suggest(
+        labels=centered_pair_predictions,
+        params={
+            "method": "sample",
+            "per_video": 2 * vid_frames,
+            "sampling_method": "stride",
+        },
+    )
+    assert len(suggestions) == 1
+
+    # Testing typical videos that have more frames than desired Samples per Video value using stride method.
+    # Expected result is the desired Samples per Video number of frames.
+
+    suggestions = VideoFrameSuggestions.suggest(
+        labels=centered_pair_predictions,
+        params={
+            "method": "sample",
+            "per_video": 20,
+            "sampling_method": "stride",
+        },
+    )
+    assert len(suggestions) == 20