when default fps was Video FPS (-1) post process had issues setting F…

client/platform/web-girder/views/Upload.vue

@@ -440,9 +440,14 @@ export default defineComponent({
         const registrationSeed = transformEntries.length
           ? await parseRegistrationSeed(transformEntries, Object.keys(args.sourceList))
           : null;
-        const fps = args.type === VideoType
-          ? DefaultVideoFPS
-          : (clientSettings.annotationFPS || 1);
+        // annotationFPS of -1 ("Video FPS") is truthy in JS; for image /
+        // large-image multicam resolve it to 1 so create_multicam matches
+        // child folders after post-process (which also maps -1 → 1).
+        const annotationFps = clientSettings.annotationFPS;
+        let fps = DefaultVideoFPS;
+        if (args.type !== VideoType) {
+          fps = annotationFps > 0 ? annotationFps : 1;
+        }
         setMulticamImportProgress(MULTICAM_PROGRESS_START, `${labelPrefix}Creating dataset folder…`);
         const { data: datasetFolder } = await createGirderFolder({
           folderId: props.location._id,

server/dive_server/crud_dataset.py

@@ -1335,12 +1335,14 @@ def create_multicam(
         loaded_children[name] = child
         camera_types_by_name[name] = cam_type
 
-    use_video_fps = validated.type == constants.VideoType and validated.fps == -1
-    if use_video_fps:
+    # fps == -1 means auto: take the children's resolved rates (video native
+    # fps, or image-sequence/large-image default of 1 after post-process).
+    use_auto_fps = validated.fps == -1
+    if use_auto_fps:
         unique_fps = set(child_fps_by_name.values())
         if len(unique_fps) > 1:
             raise RestException(
-                'All cameras must have the same fps when using video-derived frame rate',
+                'All cameras must have the same fps when using auto frame rate',
                 code=400,
             )
     else:

server/tests/test_create_multicam.py

@@ -146,6 +146,49 @@ def test_create_multicam_accepts_video_fps_sentinel(_verify, folder_cls, _aux, i
     assert saved_meta[constants.FPSMarker] == 10.0
 
 
+@patch('dive_server.crud_dataset.crud.get_or_create_auxiliary_folder')
+@patch('dive_server.crud_dataset.Folder')
+@patch('dive_server.crud_dataset.crud.valid_images')
+@patch('dive_server.crud_dataset.crud.verify_dataset')
+def test_create_multicam_accepts_image_sequence_fps_sentinel(
+    _verify, valid_images_mock, folder_cls, _aux
+):
+    """Image-sequence children resolve fps -1 → 1 in post-process; create_multicam
+    must accept request fps=-1 (auto) and take the children's rate."""
+    user = {'login': 'tester'}
+    dataset_parent = _dataset_parent()
+    left = _child_folder('left-id', 'left', fps=1.0, media_type='image-sequence')
+    right = _child_folder('right-id', 'right', fps=1.0, media_type='image-sequence')
+    star = _child_folder('star-id', 'STAR', fps=1.0, media_type='image-sequence')
+
+    folder_cls.return_value.load.side_effect = lambda fid, **kwargs: {
+        'left-id': left,
+        'right-id': right,
+        'star-id': star,
+    }[fid]
+    valid_images_mock.return_value = [MagicMock(), MagicMock()]
+
+    data = {
+        'name': 'stereo-set',
+        'fps': -1,
+        'type': 'image-sequence',
+        'subType': 'multicam',
+        'defaultDisplay': 'STAR',
+        'cameraOrder': ['left', 'right', 'STAR'],
+        'cameras': {
+            'left': {'folderId': 'left-id'},
+            'right': {'folderId': 'right-id'},
+            'STAR': {'folderId': 'star-id'},
+        },
+    }
+
+    result = crud_dataset.create_multicam(user, dataset_parent, data)
+
+    assert result == dataset_parent
+    saved_meta = folder_cls.return_value.save.call_args_list[-1][0][0]['meta']
+    assert saved_meta[constants.FPSMarker] == 1.0
+
+
 @patch('dive_server.crud_dataset.crud.valid_images')
 @patch('dive_server.crud_dataset.Folder')
 @patch('dive_server.crud_dataset.crud.verify_dataset')