Make pyav loading code handle tRNS PNG. (Comfy-Org#13607)

Author: comfyanonymous

comfy_api/latest/_input_impl/video_types.py

@@ -284,7 +284,7 @@ def get_components_internal(self, container: InputContainer) -> VideoComponents:
 
                         if not checked_alpha:
                             for comp in frame.format.components:
-                                if comp.is_alpha:
+                                if comp.is_alpha or frame.format.name == "pal8":
                                     alphas = []
                                     image_format = 'gbrapf32le'
                                     break